Duke PHYSICS
http://www.phy.duke.edu
WHAT’S INSIDE
Department Happenings......... 1
Graduate News....................... 2
Graduate Student
Organization News.................. 4
Undergraduate News.............. 6
New Faculty Profile................. 7
Faculty Awards....................... 8
Six Big Questions................. 12
Alumni Profiles:
Jacob Foster.......................... 9
Katie Hulme.......................... 10
Will Sager............................. 11
Research:
The Higgs at Duke................ 14
Homing in on the
Higgs Boson Mass................ 16
Chinese-American
Collaboration in Hadron
Physics Bears Fruit............... 17
Spotlight on
Applied Physics.................... 18
Perspectives on
the “Jamming by Shear”........ 19
Electron Neutrino
Appearance in the T2K
Experiment........................... 21
KamLAND-Zen Started
Zero-Neutrino Double-Beta
Decay Search....................... 21
Outreach............................ 22
News................................... 24
Staff Highlight.................... 28
Editors: Haiyan Gao, Cristin
Paul, Mary-Russell Roberson and
Christopher Walter
Annual Newsletter 2012
Department Happenings
– by Haiyan Gao
This has been a hectic, eventful and productive
year. First, let me thank you all for your support,
without which my first year as chair would be a lot
less enjoyable, and harder.
There has been an important change in
the departmental leadership. After three years
of outstanding service as Associate Chair for
Teaching (ACT), Prof. Stephen Teitsworth stepped
down on July 1, 2012, and Prof. Ashutosh Kotwal
took over this important leadership role. We thank
Prof. Teitsworth for his service to the department
and look forward to working with Prof. Kotwal in
his new role.
The commencement weekend has always
been the happiest time for the university. We
were particularly thrilled this May – we graduated
our first Biophysics majors in May 2012. You
will read more in the section on undergraduate
studies in this newsletter, contributed by Prof.
Henry Greenside, Director of Undergraduate
Studies. With the support of Arts and Sciences
and the university, our department signed an
agreement on student exchange from Shandong
University and the first five students from Taishan
College at Shandong University will join us this
fall. You can read more about this program and
meet these five students in this newsletter.
We are very happy that Dr. Maiken Mikkelsen
from University of California, Berkeley will join us
this fall as a tenure-track Assistant Professor. Dr.
Mikkelsen will hold a joint appointment between
our department and the Electrical and Computer
Engineering (ECE) department in the Pratt School
of Engineering. You will meet and learn more
about Dr. Mikkelsen and her research in the
new faculty profile in this newsletter. We also
added a few new secondary faculty members
to our department in 2012. They are Prof. Tom
Katsouleas (ECE) and Dean of Pratt School of
Engineering, Prof. Weitao Yang (Chemistry), and
Prof. Warren Warren (Chemistry), and I have listed
their primary departments in parentheses. Profs.
Steffen Bass and Kate Scholberg have been
promoted to the rank of Full Professors, and Prof.
Nick Buchler has been reappointed as a tenuretrack Assistant Professor. Congratulations to all
for these important milestones.
On the staff side, we welcome Ms. Connie
Blackmore as the new DUS assistant, whose
responsibilities include the new Duke-SDU student
exchange program. We are also very happy that
Ms. Miriam Vines assumed the Physics’ Grants
and Contracts position on June 1, 2012. Miriam
had been the support
person for the highenergy physics (HEP)
and nuclear physics
theory (NPT) groups in
our department prior
to this new position.
We are very happy
that Jennifer Westerfeldt started in July 2012
as the new Physics Staff Assistant for the HEP
and NPT groups. Ms. Manuela Damian and Ms.
Elena Musty departed from our department to
take on new roles in other parts of the university
and we wish them all the best in their new
responsibilities.
In the last year faculty and students have
published many exciting research results and you
can sample some of them in this newsletter. We
are also very proud that several of our students
and faculty have received awards, which are also
listed in this newsletter.
Physics is a mature and evolving
scientific discipline, and has witnessed many
breakthroughs. In the 21st century, physics is
poised for more discoveries and breakthroughs,
many of which will come out of interdisciplinary
research and teaching. In the last several years,
faculty in our department had been working on
better ways to articulate and present our work
to prospective students, our undergraduate and
graduate students, and to others both inside
and outside of Duke. The result is a document,
“Six Big Questions” that the faculty prepared and
approved in summer of 2011 to help guide our
planning, research, teaching and communications
as we move forward. I hope you enjoy reading
these big questions in this newsletter.
In closing, I would like to thank you for your
support of our news program by contributing
your stories and sharing with us the happiness
of your achievements. Our students are
particularly interested in the stories of our alumni.
Please continue to share and contribute to the
departmental news program. In the last year, the
need for a new Physics Building has been heard
widely on campus and we believe the case has
been made. The most urgent, and important step
next, is to raise funds for this new building. If you
have great ideas about how to make this happen,
we will be extremely happy to hear from you. We
look forward to the 2012-2013 academic year
and hope it will bring new hope for a new physics
building.
Graduate News
Graduate News
- by Director of Graduate Studies, Shailesh Chandrasekharan
Last year (July 01, 2011 – June, 30 2012) was an eventful year with many exciting news to report. First, there
was a change in the administration and I took over the role of the Director of Graduate Studies (DGS) from
Professor Richard Palmer in July. While I have enjoyed my new role, there was a lot for me to learn about my new
responsibilities. It was a busy but exciting period for me. I thank Donna Ruger, who is the assistant to the DGS
for helping make the learning process easy and the transition smooth. Below I describe other exciting graduate
news.
Photo by Michele Dubow
Degrees Awarded
Fourteen students obtained their final degrees in May. One of them obtained a terminal Master’s while the remaining received PhD
degrees. These students and their advisors are listed below.
Student
Advisor
Student
Advisor
Joshua Albert
Prof. Chris Walter
Dong Liu
Prof.Harold Baranger
Ivan Borzenets
Prof. Gleb Finkelstein
Henok Mebrahtu
Prof. Gleb Finkelstein
Leah Broussard
Prof. Calvin Howell
Sukrit Sucharitakul
Prof. Gleb Finkelstein
Chenglin Cao
Prof. John Thomas
Hung-Ming Tsai
Prof. Berndt Muller
James Esterline
Prof. Werner Tornow
Wenzong Wu
Prof. Ying Wu
Joel Greenberg
Prof. Dan Gauthier
Yu Zeng
Prof. Ashutosh Kotwal
Botao Jia
Prof. Ying Wu
Wangzhi Zheng
Prof. Haiyan Gao
Graduation Photograph (left to right): Shailesh Chandrasekharan (DGS), Chenglin Cao, Joel Greenberg, Joshua Albert, Leah Broussard, Wangzhi Zheng, Haiyan Gao (Chair), Henok Mebrahtu and Dong Liu.
Among the PhD degree recipients, four are taking up jobs in the Industry while the remaining move on to postdoctoral positions at various
universities around the world.
2
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u !
Duke PHYSICS
Fellowships, Awards and Accomplishments
Many students received fellowships and awards this year. Huaixiu Zheng, a fourth year student, received the John T. Chambers award
for his research with Professors Harold Baranger and Daniel Gauthier on waveguide QED. The award pays for his tuition and fees for one
academic year along with a generous stipend. This is an award given to outstanding students associated with the Fitzpatrick Institute for
Photonics at Duke.
Huaixiu Zheng
Ivan Borzenets
Dong Liu
Chenglin Cao
Georgios Laskaris
Jonah Bernhard
Chung-Ting Ke
Zepeng Li
Margaret Shea
Yang Yang
Kyle Kalutkiewicz
Chris Varghese
Cate Marcoux
Kevin Finelli
Sixth year students Ivan Borzenets and Dong Liu, who completed
their PhDs this year under the guidance of Professors Gleb Finkelstein
and Harold Baranger respectively, jointly won the Fritz London graduate fellowship, given to outstanding students performing research
in condensed matter physics. Ivan and Dong are going to Tokyo
University and Michigan State University respectively, for postdoctoral
positions. Chenglin Cao, another sixth year student who received his
PhD under the guidance of Professor John Thomas, won the Walter
Gordy prize given to outstanding students in the field of atomic,
molecular and optical physics. Chenglin begins his postdoctoral work
at the University of Maryland in July 2012. Georgios Laskaris, a fourth
year student working with Professor Haiyan Gao, won the Henry
Newson fellowship given to outstanding students in experimental
nuclear physics. Zepeng Li, a first year student, was awarded the
Goshaw fellowship for his first year, which covers his tuition and fees
including the summer and relieves him from teaching assistant duties
so as to begin his research in the high-energy physics group. He is
working with Professor Chris Walter. Margaret Shea, another first year
student, was the recipient of the Townes-Perkins-Elmer award. The
above awards are given to outstanding physics students every year
based on the corresponding endowment grants.
In addition to the above awards, the University provides many
fellowships to outstanding students every year. Yang Yang, a fifth year
student, working with Professors April Brown and Henry Everitt, on an
interdisciplinary thesis covering materials physics and electrical engineering, received the Katherine Goodman Stern fellowship to complete
his PhD thesis during the 2012-13 academic year. This fellowship pays
for tuition and fees along with a stipend for the entire year. Two first
year students, Kyle Kalutkiewicz, and Margaret Shea, and one second
year student, Chris Varghese, received summer fellowships from the
graduate school to work on physics projects of their interest. These fellowships pay tuition and fees along with a stipend for the summer. Kyle
is interested in theoretical Physics, Meg is excited about experimental
high energy physics while Chris is interested in complex networks. Meg
also won the University Scholars award.
Chenglin Cao, who was already mentioned above, and Wangzhi
Zheng, another sixth year graduate student who worked with Professor Haiyan Gao and obtained his PhD this year, received the 2011
outstanding graduate student award from the Ministry of Education of
China. This award is dedicated to Chinese graduate students studying
abroad. There are a total of 495 students that received this award in
2011. They are from 29 countries with research areas in more than
60 different disciplines. This year three Duke Chinese students received this award and two of them are from the Physics department.
In addition to the above, other graduate students have received
awards for various accomplishments. Students continue to publish
important research articles in various journals and some have been
given the best research presentation awards at conferences. Some
students have won teaching awards for their excellent teaching skills.
We refer the reader to the web site http://news.phy.duke.edu/topics/
graduate-studies-news/ for detailed information about these and other
graduate news.
First-year graduate student Jonah Bernhard and second-year
graduate student Chung-Ting Ke have been named 2012 Outstanding
Teaching Assistants of the American Association of Physics Teachers
(AAPT).
Winners of the 2012 Mary Creason Memorial Award for Undergraduate Teaching are Cate Marcoux and Kevin Finelli for outstanding
teaching in the introductory physics laboratories at Duke University.
Graduate Curriculum
The graduate curriculum committee, which reviews curriculum
related issues in an effort to improve the graduate program, was quite
active this year. Among its accomplishments was a new format for
the Annual Report that students submit every year. A new feature of
the report is a section where the advisor gives written feedback to
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u ! 3
Graduate News
continued from page 3
the students on their progress and suggestions for improvement where necessary. The committee contains a student
representative and welcomes suggestions and feedback from students that help to improve the graduate program.
Graduate Admissions
An important event every year is the graduate admissions, which keeps the graduate admissions committee busy
during the months of December and January. This past year we received 272 applications for admission in Fall 2012.
We made 42 offers for 12 positions authorized by the graduate school, and were successful in recruiting 10 students.
The incoming class contains students from China (4), Cyprus (1), and USA (5). Three of them are female students.
Two of the incoming students have already received government fellowships to pursue their PhD degrees. We expect
the new class to arrive during mid August and as usual we have planned a variety of orientation activities for the
incoming students including a departmental picnic on August 25, 2012.
Wangzhi Zheng
Graduate Student Organization News
–by GSO President, Kevin Claytor
Annual Picnic
The rising second year students organized the annual picnic, held
this year in the French Family Science Center atrium. This event saw
the official welcoming of the new students to the department. The
Outstanding Teaching Assistant Awards were bestowed upon Sukrit
Sucharitakul and Chris Pollard at the picnic as well.
New Student Orientation
During the new graduate students’ orientation to Duke and the physics department, the physics graduate student organization helped
introduce them to Durham. These included trips to the local Farmer’s
market, the Museum of Life and Science, and a Durham Bulls game.
Grad-Chair meetings
Five lunchtime meetings saw the graduate students meet with the
chair, Prof. Gao, and have brought student concerns directly to the
department this year. These permit the graduate students to keep up
with long and short term goals of the department, while the faculty
can address issues facing the students.
Department Tea
Graduate student, post-doc, and faculty turnout for the department
tea, held at 4:30 PM in the Faculty lounge, has been holding strong as
interesting discussions sprout around vegetable dip, crackers, and hot
Earl Gray Tea. Some memorable treats included foreign and homemade deserts brought in by faculty members.
Graduate Student Seminar
The graduate student seminars were well attended this year. They were
organized by Sean Finch in the fall and Georgios Laskaris in the spring.
At least six talks were given, with topics ranging from atomic and optical physics, to high energy physics at CERN, to granular materials.
Participation in New Professor Search
Demand was high among the graduate students for lunch with the
prospective faculty candidates. Many students took the opportunity
to learn about the hiring process first hand, in addition to sharing the
unique advantages Durham and the Duke Physics department has to
4
offer, and learning about research at other
institutions.
Mentoring Program
The mentor-mentee program is alive and
well under the guidance of Yang Yang this
year. This program pairs up two older graduate students with a first
year graduate student to help acclimate them to the department and
Durham. One of the yearly highlights is a Thanksgiving dinner held at
the department.
Open House Week
The graduate students showed their enthusiasm for physics during the
prospective graduate student weekend. This was exemplified by the
turnout for the poster session, held in the LSRC, where posters were
even taped to the walls after the stands ran out. The graduate student
seminar schedule was adjusted so that the visiting students could attend. Abe Clark’s fantastic presentation on impacts in granular media
sparked interesting conversations between the current and future
grad students. Later in the afternoon, the visiting students were able
to interact with faculty and graduate students in the informal tea time.
Finally, the prospective students had an opportunity to visit downtown
Durham with a dinner at Pop’s Trattoria.
Thanks!
The physics GSO would like to give its thanks to all those who helped
make this a productive year. The GSO executive council consisted
of Kevin Claytor (President), Ben Cerio (Vice President), Taritree
Wongjirad (Secretary/Treasurer), Junyao Tang (6th year rep),
Mengyang Sun (5th year rep), Christopher Coleman-Smith (4th year
rep), Chris Pollard (3rd year rep), Chris Varghese (2nd year rep),and
Timm Puttkamer (1st year rep). Thanks also goes to our subcommittee chairs and positions; Marco Bertolini (Graduate Curriculum),
Joshua Powell and Huaixiu Zheng (Graduate Colloquium), Sean Finch
and Georgios Laskaris (Graduate Seminar), Bonnie Schmittberger
(Newsletter), Georgios Laskaris (GPSC Representative), and
Mengyang Sun (Election Comissioner).
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u !
The First Year in the Graduate Program at Duke Physics
Photo by Cristin Paul
l-r: Bernhard, Shea, Collar, von Puttkamer
— by Mary-Russell Roberson
What do first-year graduate students like about Duke Physics? “It’s a
strong department—strong in many different areas,” says Meg Shea,
who earned her BS at Yale. “Here there are lots of options.”
Shea likes the structured way in which the department introduces
new graduate students to all the options. In a series of seminars over
the course of the year, professors from each research group give
talks about their work. The seminars include dinner, and the casual atmosphere allows students to get to know members of the faculty and
their research. Shea appreciates the fact that incoming students don’t
have to commit to a specialty and an advisor right away, as students
at some universities do.
She has worked with the high-energy experimental group this
summer. “My goal is to figure out if the day-to-day life of a high-energy
experimentalist will suit me,” she says. The students say most of them
will probably end up choosing an advisor from the group they work
with this summer, although even then it’s not too late to switch to
another group.
Jonah Bernhard, from Swarthmore College, says he was attracted to the interdisciplinary opportunities at Duke. He’s interested
in applied physics—fabricating materials or devices. “If the professor
you want to work with is in chemistry or engineering you can do that,”
he says.
Timm von Puttkamer, who graduated from Goethe University
in Frankfurt, Germany, also likes the interdisciplinary nature of Duke
Physics. He wants to study mathematical physics and string theory.
“At my home university, math and physics were in completely different
places in the city,” he says. “Here they are across the hall.”
Although the students say the work load is heavy, and they are
expected to be more self-directed than in college, they have found the
department to be supportive. Kristen Collar of Florida State University
says, “Some of the other programs I looked at had a competitive
atmosphere among the students. I wanted a department where they
wanted me to be here and wanted me to make it.”
The students say the department is flexible and responsive in
meeting their needs. “Our director of graduate studies is really approachable,” Shea says. “He really wants to make sure we’re happy
and on the right track.”
The students attend classes, study and work 50-60 hours a
week, but they also find time for fun. Collar, Von Puttkamer, and eight
other physics graduate students participated in the basketball ticket
camp-out this fall. They camped out in a U-Haul outside Cameron
Indoor Stadium for a weekend to earn the right to be in a lottery to
win season tickets. Seven of the ten of them did win season tickets,
which they then divvied up among the other graduate students in the
department. Collar says the camp-out was a great way to meet graduate students from other departments at Duke.
Meeting other graduate students in the physics department
requires no effort at all. The offices of the first-years are all in one
location and most of the students are taking the same classes. “When
you get stuck, you have instant support or feedback or discussion,”
says Collar.
Getting to know older graduate students and faculty happens in
a variety of formal and informal settings, including classes, labs, colloquia, graduate student presentations, and a weekly departmental tea.
Shea says, “I find it a very friendly department. If you want, there’s
plenty of opportunity to interact with people in the department.
People often eat lunch together and socialize together.”
The first-years feel well-supported financially and say that as long
as they are working hard and making progress, they will continued
to be supported throughout their stay here. The department doesn’t
“over admit,” so there’s not a forced, financially based weeding-out
process. Most students earn stipends by serving as teaching and/
or research assistants, and professors keep students informed about
available scholarships and encourage them to apply.
Living in Durham on a graduate student budget is a bit easier
than in larger cities in the northeast or west coast. Shea says, “The
cost of living is so much lower in Durham than many of the places
I was looking. I’m paying less for a two-bedroom apartment that’s
just for me than my friend in Boston who is sharing a place with four
people.”
All told, these first-year graduate students are happy with the
strength, breadth, flexibility, supportiveness, and interdisciplinary
nature of Duke Physics.
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u ! 5
Undergraduate News
- by Director of Undergraduate Studies, Henry Greenside
I would like to summarize some highlights of this last academic year,
2011-2012, as related to our physics and biophysics undergraduates.
This May of 2012, the Physics Department was delighted to
see seventeen primary majors (14 BS students and 3 BA students)
graduate, as well as fourteen students who double majored with
physics as their second major (with engineering being the most
common primary major) for a total of 31 seniors who graduated with
physics as one of their majors. This is one of the largest classes of
graduating majors ever in the Department. This year’s class also
had some unusually strong students, for example one student (Vivek
Bhattacharya) was awarded a Barry Goldwater fellowship (a national
award for academic excellence and promise related to science) while
a second student, Farzan Beroz, received an honorable mention for
this award. Four seniors were Phi Beta Kappa, which means they were
among the strongest students among all Duke seniors.
Five physics seniors wrote and successfully defended honor
theses, with one student graduating with distinction and four
graduating with high distinction (the highest honors possible in the
Physics Department). The theses concerned diverse topics such as
a novel way to simulate a quark-gluon plasma, an improved statistical
technique for finding novel particles at the Large Hadron Collider, a
theoretical analysis of a novel condensed matter state consisting of
a non-periodic tiling of a single tile, experiments and theory related
to building a quantum key distribution system using nonlinear optics,
and a novel statistical analysis of supernova neutrino events in water
Cherenkov detectors. Seniors Travis Byington and Vivek Bhattacharya
shared this year’s Daphne Chang Award of $1,000 for the excellence
of their theses. (See the webpage http://www.phy.duke.edu/about/
DaphneChang/MemorialAward.php for information about this award.)
Given the high quality of the research carried out by all of our
seniors (not just those who write a thesis), the Physics faculty wishes
to express its appreciation of the many talented and enthusiastic
students who become their collaborators and friends.
As has been the case over the last decade or so, only about half
of the primary majors are going to physics graduate school, with the
other half pursuing diverse interests, including taking some gap years
to travel, teach, do some physics-related research, develop software,
and startup a company. Some others are pursuing graduate school
outside of physics and some are pursuing other professional degrees.
This May also saw the graduation of Duke’s first two Biophysics
majors, Tony Phipps Jr and TJ Hu. Tony will be going to medical school
and TJ will become a graduate student in cell biology at the University
of California at San Francisco, to pursue research related to cancer.
The number of biophysics majors has been steadily increasing since
the biophysics major begin in fall of 2010 and there are currently
fourteen biophysics majors. At the present rate of growth, the steady
state number of biophysics majors will correspond to 8-10 per year.
The Physics Department is pleased to see this substantial increase
in the total number of students taking physics courses and doing
research with our faculty.
During the next year, the Physics Undergraduate Curriculum
Committee (UCC) will be setting two main goals. One is to improve
the introductory physics courses 161 and 162 (formerly numbered 41
and 42) for potential majors, and for the intro physics course taught
mainly for life science students (premeds), 141 and 142 (formerly
numbered 53 and 54). For 161 and 162, one goal will be to mention
more systematically connections of the material to current frontiers
of physics so that, by the end of the freshman year, students will have
a better sense of some of the exciting questions that Duke faculty
and other physicists are pursuing. For 141 and 142, the UCC will be
exploring ways to make the material more relevant for future
biologists and medical doctors while still conveying some of the grand
insights and quantitative style of thinking that is the hallmark and
presumably the benefit of premeds taking a physics course. These
changes will also be coordinated with substantial changes that will
take place in 2015 for the Medical College Admission Test (MCAT),
and take into account the knowledge of the biophysics faculty of how
physics is and will be useful to biology.
A second goal will be to evaluate and then improve the education
of our majors in terms of experimental physics. Currently, majors who
do not do experimental research learn about experimental physics
through labs associated with the sophomore Modern Physics course
(PHY 264, formerly numbered 143) and through a one-semester
advanced physics lab course (PHY 417S, formerly 217S). Professor
Dan Gauthier is currently leading a committee that will identify
what experimental knowledge and skills we want Duke physics and
biophysics majors to graduate with, and then make recommendations
about how to teach these skills, either by revising existing courses or
perhaps by introducing a new course.
You can view pictures of the 2012 graduation ceremony
and luncheon here: http://www.phy.duke.edu/undergraduate/
pictures/2012-physics-graduation.
Photo submitted by Henry Greenside
2012 Physics and biophysics graduates. From left to right: DUS Prof. Greenside, Laura Dodd, Shreyen Sen, TJ Hu, Farzan Beroz, Ken Wong, Austin Ely, Wesley
Johnson, David Mayer, Jacqui Bascetta, Ben Bellis, Robert Helms, Tony Phipps Jr, Andrew Ferrante, Alex Cortese, Travis Byington, Ryan Magee, Yingyi Shen,
Theodore Frelinghuysen, and Physics Chair Professor Gao. Missing are: Konrad Dudziak, William Grisaitis, Jess Hilaire, and Amir Malek.
6
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u !
New Faculty Profile
New Assistant Professor
Maiken Mikkelsen: Using Physics
to Build a Better Computer
–by Mary-Russell Roberson
“It’s unusual and exciting to build bridges between physics and
engineering,” says Maiken Mikkelsen, who will be doing just that
in her new position as assistant professor in the departments
of physics and electrical and computer engineering. “I’ll be able
to supervise students from both departments and create a very
interdisciplinary group. I’m excited about it,” she says.
In addition to building bridges between disciplines, she’s also
helping to “build” the computer of the future—a quantum computer.
Quantum mechanics describes how matter and energy interact on
an atomic scale, where the familiar laws of classical mechanics
do not apply. “As electronics get smaller and smaller, at some
point the quantum mechanics are starting to become important,”
she says. “Let’s not look at quantum effects as annoyances, but
build something from the ground up that is based on quantum
mechanics—to use it as an advantage.”
While quantum computing is still just a gleam in physicists’
eyes, the idea is tantalizing because a quantum computer could
handle much more information—and much more securely—than
today’s computers.
In digital computers, data is stored in switches that are either
on or off—the familiar 1’s and 0’s of computer language. In a
quantum computer, data is stored in quantum bits—“qubits”—
that can be on, off, or essentially anywhere in between (called
superposition), dramatically increasing the amount of information
that could be stored and processed. Qubits can be electrons, nuclei,
or photons, among others.
In her research, Mikkelsen studies electrons and their
potential as qubits. She uses quantum dots, which are nanoscale
semiconductor structures with spatial confinement in all three
dimensions, to measure and manipulate a single electron spin. By
measuring the polarization of light reflected off the quantum dot, she
can tell the orientation of the spin. Then using an ultrafast optical
pulse, she can rotate the spin to any orientation. She’s also done
research on how to prepare, or initialize, electron qubits to receive
and transmit information.
While physicists have already designed and built working qubits,
she says, “One of the main challenges is how to scale things up—to
connect multiple qubits together.” She’s interested in experimenting
with circuits that use photons rather than electricity to connect
qubits.
In addition to being faster and able to hold more data, quantum
computers could transfer data more securely because the act of
eavesdropping would change the nature of the qubits. As Mikkelsen
says, “It would allow for completely secure communication; if
someone looks at it from the outside, it’s destroyed.”
Mikkelsen is also interested in other kinds of nanoscience,
optics, photonics, and materials science, all of which offer fruitful
areas for exploration at the intersection of physics and engineering.
As a child, Mikkelsen says she was fascinated with trying to
understand how the world works, and became interested in physics
even before high school. That curiosity has never waned. “I love
doing the experiments,” she says. “I do very hands-on, table-top
experiments—it’s like a great playground.”
Mikkelsen visited Duke in June to begin designing her lab. She
was heading to Denmark for a visit to her childhood home before
returning to UC-Berkeley to wrap up her post-doctoral work, then
flying up to Alaska for a two-week vacation. She starts at Duke
September 1. “It’s a great environment for quantum computing,
photonics, and metamaterials,” she says.
Although her research into different aspects of quantum
computing certainly has potential practical applications, she says,
“It could also go in a lot of different directions that we’re not even
imagining right now. It’s both practical and pushing the envelope.
To me, it’s fundamentally exciting just to understand how nanoscale
quantum mechanical systems really work.”
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u ! 7
Faculty Awards
Arce Receives Career Enhancement Fellowship
Prof. Ayana Arce has been selected as a recipient of the 2012 Career Enhancement Fellowship for Junior Faculty by
the Woodrow Wilson National Fellowship Foundation.
Gao Named Henry Newson Professor of Physics
Prof. Haiyan Gao was named Henry Newson Professor of Physics in Trinity College of Arts and Sciences, effective
July 1, 2012.
Hastings Named Simons Foundations Investigator
Prof. Matthew Hastings has been named one of twenty-one Simons Foundations Investigators. The award recognizes
Hastings’ work in mathematical physics and quantum information theory on fundamental problems of interacting
quantum systems.
Kruse Named New Bass Fellow
Prof. Mark Kruse has been named a new Bass Fellow and holds the Fuchsberg-Levine Family chair effective July 1,
2012.
Hannah Petersen Selected for
Helmholtz Young Investigator program
Visiting Assistant Professor Hannah Petersen was selected by the Helmholtz Association in Germany to lead a Young
Investigator Group. This program offers the possibility to young scientists within 2-6 years after having received their
PhD degrees to build their own research group. The funding over a 5-year period consists of a total sum of 1.25 million Euro (approximately $1.7M).
8
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u !
Alumni Profiles
Foster Works at the
Intersection of Physics
and Sociology
— by Mary-Russell Roberson
What’s an alumnus of the Duke Physics department doing as a postdoc in the sociology department at the University of Chicago? Ask
Jacob Foster ’03, who is doing just that. “Many of the most interesting
and challenging problems for people who want to work on complex
systems are in the social sciences,” he says. Foster, who earned his
PhD in physics from the University of Calgary, adds, “The training I got
at Duke and at Calgary put me in a pretty good position to act as an
interpreter between the two disciplines.”
Foster applies his physics-based knowledge of complex systems
to questions in the social sciences involving other kinds of complex
systems—such as human interactions. He first became interested in
complex systems as a physics undergraduate, working with Professor Henry Greenside. He also became interested in the study of
knowledge at Duke while taking a literary theory class from Professor Thomas Ferraro. After studying mathematical physics at Oxford
as a Rhodes Scholar, he went to the University of Calgary, where he
worked with the complex systems group in the physics department.
While at Calgary, he attended an interdisciplinary workshop on the
social sciences and the “new sciences”—in this case, complex
systems and quantum information science. At the workshop, he spoke
to a Calgary sociologist about the similarities between ideas in social
theory and complex systems. The conversation reignited Foster’s
longstanding interest in translating between narrative and mathematical languages to answer emerging questions related to the formation
of knowledge and ideas. As a result of that conversation, he was introduced to James Evans at the University of Chicago, who later offered
him a post-doc position.
“I was very fortunate that James Evans was looking for someone
who had a complex networks background,” Foster says, “and I was
looking for a sociologist who could help me complete my training so I
could do research in a cross-disciplinary space between physics and
sociology. It just works out brilliantly.”
Evans and Foster published an essay in the February 11, 2011
issue of Science titled “Metaknowledge” (http://www.sciencemag.
org/content/331/6018/721.full). Foster says the “data deluge” in the
digital world presents new research opportunities. Evans and Foster
plan to use computational techniques to mine the data deluge to learn
how cognitive and social factors influence the progress and path of
science. “Metaknowledge means knowledge about knowledge,” Foster
says. “It involves looking at the distribution of various quantities of
interest across a vast landscape of millions of scientific publications.
Fairly small signals, aggregated over millions of articles, leave enough
of a trace that you can detect the effects of biases, heuristics, or
preferences—and start imagining how you could build a procedure to
account for them.”
For example, he says, the process could be used to learn why
certain areas of science have been investigated heavily, while other
areas are investigated lightly or not at all. In some cases the reason
may be based on science, but in other cases the reason may be
based on the social context, such as the beliefs of one or two leading
authorities in the field. “You can identify areas where a consensus that
something was important or unimportant may have been achieved
prematurely,” he says. This kind of information could help scientists
and funding agencies be more strategic when choosing projects to
pursue.
After his post-doc, Foster hopes to find a faculty position where
he can continue his interdisciplinary work. He’d also like to encourage
students to think between disciplines, just as his Duke professors
encouraged him.
“The folks in the physics department were always very encouraging in terms of me thinking about odd things,” Foster says. “I did my
senior thesis with Berndt Mueller on physics with two time dimensions. And Josh Socolar advised me to take a literary theory course
instead of a graduate physics course. He told me I could always take
more physics but I might not have an opportunity to take a literary
theory course as a graduate student.”
Foster says he’d like to reach out to students like himself—
people with a solid mathematical and analytical background who
are able to get excited about emerging questions in other data-rich
fields. “We’re all aware of the challenging questions in physics these
days, but your typical undergraduate physics major has no idea that
there are equally fascinating and perhaps practically more important
research going on right now in statistics or sociology. As the world of
data continues to grow and as we anticipate all these challenges—climate change, how to build an economy on information and ideas—the
questions in social science will really become an incredibly fruitful
place for these students to work.”
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u ! 9
Hulme Works as Diagnostic Physicist at Cleveland Clinic
—by Mary-Russell Roberson
Katie Hulme, a diagnostic physicist at the Cleveland Clinic, measures
the skin exposure for an abdomen X-ray technique using an ANSI
“phantom,” which mimics the attenuation characteristics of X-rays in
the human body.
After earning her undergraduate degree in physics at Duke
in 2007, Katie West Hulme earned a master’s degree in medical
physics at MD Anderson in Texas. She says she thought about going
to physics graduate school, but was looking for something more
applied. Then she read an article in Duke Magazine about medical
physics. “It looked like a very applied field,” she says. “You have not
only the theoretical component, but you interact with a lot of different people. So that sparked my interest.”
Today she is a diagnostic physicist in radiology at the Cleveland Clinic, with a specialty in general radiography–using X-rays
to make images of the human body. She’s working on getting her
FDA certification in mammography. “I do a lot of quality control,”
she says. “The biggest part of my job is determining what needs to
be tested and how often we need to test it.” In addition to making
sure all current equipment is working correctly and compliant with
state regulations, she also tests and calibrates new equipment after
it is installed. She also helps set up clinical protocols to optimize
the balance between image quality and the dose of radiation the
patient receives. She doesn’t read images—that’s the job of radiologists—but if there’s an issue with an image due to the equipment,
she might help troubleshoot it. In the coming years, she’ll add job
responsibilities as she gains experience. For example, physicists on
her team sign off on blueprints for treatment rooms in new buildings
and compute the radiation dose estimates for a fetus if a pregnant
patient needs a CT scan.
After working at the Cleveland Clinic for a year and a half, she
says, “I get to interact with a whole host of people from clinical
administrators, radiologists, technologists. I like that my job is to
approve things, so there is a tangible aspect to what I do. I like that
there is a teaching component—I do a lot of training sessions with
our technologists and I work with radiology residents. I like the variety—every day is very different.”
Katie Hulme, a diagnostic physicist at the Cleveland Clinic, measures the skin exposure for an abdomen X-ray technique using an ANSI “phantom,”
which mimics the attenuation characteristics of X-rays in the human body. Photo submitted by Katie Hulme.
10 S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u !
Will Sager on the R/V Marcus G. Langseth research ship with Honolulu in the background, just before heading out to Shatsky Rise in the Pacific, July 2010.
Sager Uses Remote Sensing to Make Sense of Ocean Basins
— by Mary-Russell Roberson
When Will Sager was majoring in physics at Duke, he wanted to go
into astronomy, but an intro geology course opened up a new vista. “I
took Geo 101 at Duke and it was really interesting,” Sager says. “The
professor said to me, ‘You ought to consider geophysics,’ and I said,
‘What’s that?’”
Today, Sager is a professor in the departments of oceanography
and geology and geophysics at Texas A&M, where he also holds the
Jane and R. Ken Williams ’45 Chair in Ocean Drilling Science, Technology and Education. He says, “I’m a geologist who uses physics principles
to explore the structure and history of ocean basins.”
After graduating from Duke in 1976, Sager went to the University
of Hawaii to study marine geophysics. “Before too long, I was out on
a research ship,” he says, “and I thought it was really cool—collecting
data in blank spots in the ocean, exploring places people have never
been.”
He’s now been on more than 40 scientific cruises, most recently
a trip to the middle of the Pacific Ocean in the summer of 2010. Sager
and his colleagues used sound waves to map the structure of Shatsky
Rise, an underwater mountain range the size of Arkansas. Air guns on
the ship produce sound waves that travel through the crust and reflect
back to the ship, where they are picked up by 6-kilometer-long “streamers” of hydrophones trailing in the water behind the ship. “Sound waves
allow us to make an image of what’s below the surface,” he says. “It’s
like an X-ray of the crust beneath the ocean. We can see sedimentary
layers on top, and packages of lava flows under that.”
Instruments on the ship also continually measure gravity and
magnetic properties of the crust. Gravity data gives information about
the density of the rock layers, and magnetic data helps locate past
locations of mid-ocean ridges, which are plate boundaries where new
oceanic crust is churned out.
The image that Sager has put together using the data collected
on the trip indicates that Shatsky Rise is formed of volcanic rock that
erupted over a relatively short period of time from a central source—a
so-called “supervolcano.” This fits with the hypothesis that the mountain represents a mantle plume—a huge “bubble” of molten rock that
rises through the mantle and erupts on top of the Earth’s crust.
The magnetic data indicates that Shatsky Rise formed at the junction
of three ancient mid-ocean ridges. Sager is trying to piece together
how mantle plumes fit in with the theory of plate tectonics, and
whether Shatsky Rise is related to those nearby plate boundaries. “We
thought we understood this when I was a graduate student, but then
we learned we didn’t,” he says. “Things look simple when you don’t
have much data, but when you look closely, it’s more complicated.”
Shatsky Rise could be an ancient analog to Iceland, which is thought to
represent a mantle plume on the mid-Atlantic ridge. “ Or,” says Sager,
“it may be another thing entirely.”
Although there’s a way in which studying the ocean bottom with
remote sensing is like studying far-off planets, one big difference is
that Sager can occasionally get his hands on samples of the oceanic
crust he is studying. In 2009, he traveled to Shatsky Rise on a drill ship
that collected rock samples. These samples allow him to corroborate
the data he collects from remote sensing.
It’s not easy studying such inaccessible parts of the planet.
Shatsky Rise is about 3,000 miles west of Hawaii; just to get there
took nine days of cruising. And it’s certainly not a pleasure cruise.
“When we go out, we’ve spent years getting ready,” Sager says, “We
work 24 hours a day, seven days a week. If I’m up, I’m on duty. It’s intellectually stimulating, but it’s pretty tiring.”
It may seem a long way from the Duke Physics building to a
scientific research ship in the middle of an ocean, but Sager says
when he first became interested in the stars, “I was told, ‘Get a good
background in physics and you’ll be set for whatever you want to do in
science.’”
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u ! 11
Six Big Questions
What Are the Ultimate Laws of Nature?
Over the past century experimental observations and theory developments have driven remarkable changes in our understanding of
the laws that govern the behavior of matter at small distances and
the character of large cosmological structures. These two apparent
disparate domains of nature are connected when theories of fundamental particles and forces on the microscopic scale are applied
to the evolution of the universe. The next few decades will reveal a
still deeper level of understanding of these ultimate laws of nature.
This progress is being driven by a new generation of experimental
tools such as the Large Hadron Collider that will probe matter with
increased precision, energy, and sensitivity. The data provided may
reveal new physics beyond our current understanding and will aid in
the development of theories of the behavior of fundamental particles
and their applications to understanding the timeline from the Big Bang
to the fate of our universe.
Duke experimental physicists are exploring the properties of
neutrinos, the origin of mass, the structure of matter, and fundamental symmetries. Duke theoretical physicists are exploring the strong
force, extensions of the Standard Model, string theory, and the gravitational probes of cosmological structures.
What are the Principles and Applications of Quantum Physics?
A revolution in our understanding of quantum mechanics and its applications is shaping the future of fundamental science and engineering. Quantum physics determines the ultimate miniaturization scale
and operating principles of nanodevices that function at the level of a
single electron, single spin, single molecule, or single photon. The full
range of phenomena permitted by the principles of quantum mechanics is coming to be understood only now, a century after its original
discovery. New techniques are directly probing such cornerstones of
quantum physics as quantum entanglement and quantum measurement. Quantum information processing—relying on entangled states
of many particles—pushes the limits of our present experimental,
theoretical, and computational approaches. One of the challenges is
to control the interaction of these complex systems with their environments, which induce decoherence and dephasing; these processes
generate the transition from the quantum-mechanical microscopic
world to the classical macroscopic world. Yet another line of inquiry
is leading to new materials with dramatic properties—graphene,
topological insulators, and spin liquids, for instance.
Physicists at Duke are developing means of quantum information
processing, studying nonlinear interaction between matter and light,
investigating transport of charge and spin in nanostructures, and
examining emergent behavior in interacting quantum systems, both in
equilibrium and far from equilibrium. Some specific subjects of study
include atomic and superconducting qubits; sub-diffraction limit optics and cloaking; “spintronics” and electronic transport in molecules,
graphene, and quantum nanostructures; and the search for exotic
phases of matter and quantum phase transitions.
12
What are the Features of Strongly Coupled Systems?
Many systems in nature are composed of strongly interacting components. In the quantum regime, examples include atomic nuclei,
ultracold atoms, quantum liquids, and new exotic states of matter,
such as the quark-gluon plasma and high-temperature superconductors. Very few quantum systems can be solved exactly, however, and
these usually correspond to weakly interacting particles or excitation
modes. Over the past decade, novel mathematical and experimental
techniques have been developed to prepare, probe, and theoretically describe the intriguing features of strongly interacting systems.
Among the amazing results is the insight that two of the coldest
and hottest systems created under laboratory conditions share the
property of being nearly perfect fluids with minimal viscosity. Another
surprising discovery is the close connection between strongly coupled
quantum systems and Einstein’s classical theory of gravity. Fascinating connections with both quantum information and graph theory have
brought novel algorithms and insights into old methods.
Duke physicists study many variants of strongly coupled quantum
systems by experimental and theoretical techniques. The experimental activities include the investigation of ultracold atoms trapped in
laser fields, the study of electrons in nanosystems and in materials
containing strongly correlated electrons, as well as the exploration
of the three-dimensional structure of nuclei and the nucleon using
high-energy electron microscopes and intense gamma-rays. Theorists
investigate transport properties of the quark-gluon plasma; use effective field theories to describe hadrons, nuclei, and atomic systems;
develop novel algorithms for the simulation of strongly coupled
systems of fermions; and apply methods derived from network theory
and quantum information theory to model ground states of strongly
coupled quantum systems.
How Do Statistical, Nonlinear and Complex Systems Work?
The vast majority of natural phenomena encountered in everyday life
can be described in terms of nonlinear interactions, which are often
a complex, collective consequence of underlying microscopic laws.
Even when the nature of those interactions is well understood, the
collective, macroscopic effects can be surprising. The surprises may
come in two forms: (1) a collection of simple particles and interactions
gives rise to intricate patterns and dynamical heterogeneity (such
as turbulence); or (2) a heterogeneous network of interacting agents
produces robust behavior with discernible coherent patterns (e.g., in
granular materials or biological systems). Studies of these phenomena are pushing the boundaries of physics and revealing unexpected
connections between seemingly disparate fields.
Physicists at Duke are exploring a broad and exciting range of complex behaviors.
Some examples include fluid flows, granular materials, gene
networks, neural tissues, semiconductors, accelerator beams, and
turbulent quark-gluon plasmas. (See also “What are the features of
strongly coupled quantum systems?”)
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u !
What Does Physics Say About Biological Phenomena?
The application of physics to biology represents one of the most
rapidly growing frontiers of physics. In fact, some of the most interesting unsolved problems in all of science are related to biology and
physics such as: How did life arise and does life exist elsewhere in the
universe? How are living creatures able to reproduce themselves faithfully over hundreds of millions of years, when the molecular mechanisms related to cellular reproduction are subject to fluctuations
related to thermal noise and small numbers of components? How do
the tens of thousands of genes and proteins in a cell interact to guide
the structure and behavior of a cell or the self-assembly a complex
organism? How do the neurons in a brain process information, and
how do they do it more efficiently and in a much smaller volume than
any existing electronic computer?
Duke physicists are excited about these and other biology-related
questions, especially because their training in areas such as statistical
mechanics, nonlinear dynamics, quantum mechanics, nanoscience,
biophysics, and instrumentation provide numerous opportunities to
make progress on these questions. Advances in biophysics also have
applications to medicine, material science, computer science, electrical engineering, mechanical engineering, energy science, and other
disciplines.
How Can We Use Physics to Benefit Society?
The search for the fundamental laws and explanations of natural
phenomena often leads to technological breakthroughs of great
benefit to society. In many cases, physicists also directly address
important technological challenges in engineering, medicine, communications, information processing, finance, environmental science, and
national security. A deep familiarity with the physical principles and
the possibilities inherent in them is critical for the development of new
techniques and for the design and implementation of practical devices
and applications. The possibilities for advancement encompass the
full range of sub-disciplines, from subatomic physics to condensed
matter and complex systems.
Physicists at Duke are actively developing new physics-based
techniques and technologies for communications; information processing; sensing with electromagnetic waves; neural networks and
statistical modeling; nuclear energy production; detection of nuclear
materials oriented towards homeland security; optimization of radiation risk versus benefits in medical imaging procedures; development
of quantitative medical diagnostic procedures; applications of properties of granular materials to defense, industries and space-engineering; and the assessment of dynamic response of plants to changes in
carbon levels in the soil and atmosphere.
Last summer, Duke Physics prepared “Six Big Questions,” a document to guide our planning, research, teaching and communications.
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u ! 13
Research
The Higgs at Duke
— by Seog Oh with contributions from Ayana Arce, Al Goshaw,
Ashutosh Kotwal and Mark Kruse
“We have it,” was what we heard at 5 AM on July 4, 2012, from the
CERN director via video link. Although we, the ATLAS collaboration,
knew of the existence of a possible Higgs boson-like signal, we did
not know that it would be the discovery we hoped for until another
experiment at the LHC, the CMS, reported a similar observation at the
ATLAS/CMS joint seminar. This discovery, a triumph for the Standard
Model that predicted its existence, is what the High Energy Physics
community of thousands of scientists around the world has been
working towards for more than 40 years. In 1966, Peter Higgs (University of Edinburgh) proposed that the universe was filled with what
was called a Higgs field. Disturbances in this field as particles move
through it cause objects to have mass. His theory was later incorporated into the electroweak theory (a part of the Standard Model), in
which spontaneous symmetry breaking produces the Higgs boson
and particles acquire mass through interacting with the Higgs field.
The Higgs boson is the final piece of the Standard Model of particle
physics, the most successful mathematical framework concerning
fundamental particles and strong, electromagnetic and weak forces. If
the new particle is indeed the Higgs boson, we can say that we understand one of most fundamental aspects of nature—how fundamental
particles obtain their masses.
This discovery was especially meaningful for us, the High Energy
Physics (HEP) group at Duke, as we constructed a crucial ATLAS detector component called the Transition Radiation Tracker (TRT), which
tracks charged particles as well as identifies electrons and were also
involved in this search with the CDF detector at the Fermilab Tevatron
Collider prior to moving to CERN.
Since 1995, Professor Seog Oh, the Duke ATLAS team leader,
played a major role in the design, prototyping, construction, installation, and commissioning of the TRT. Others involved were Dr. Chiho
Wang, Mr. Jack Fowler (engineer), Drs. William Ebenstein, Vassilios
Vassilakopoulos (now at Hampton University), ByeongRok Ko (now at
Korea University), and Doug Benjamin. It was a long journey over a
dozen years with many ups and downs, but this discovery made it all
worthwhile.
The TRT has been performing very well, being in data-taking
mode almost 100% of the time. The quality of the physics results
depends not only on a quality detector but also on understanding the
detector characteristics. Drs. Andrea Bocci and Esben Klinkby (now at
the Neils Bohr Institute), who both held the position of TRT software
convener, played key roles in calibrations and simulations of the TRT
and made the production of high quality data possible. Currently, Dr.
Bocci is an electron/gamma performance group convener, leading
the effort in understanding the ATLAS detector response to electrons,
photons, and jets, which represents a critical part in the discovery.
The discovery of this new Higgs-like boson was made in two differ-
14 ent decay modes. One mode is a Higgs boson decaying to two Z0
bosons and each Z0 decaying to two muons (μ) or electrons—for
example, H0 ->Z0Z0 ->μ+μ−μ++μ−. The other mode is decay to two
photons (or gammas). In both discovery modes, the TRT played a very
important role.
The first figure above shows an event with four muons resulting
from the decay of a Higgs boson candidate. This is a cross-sectional
view of the Inner Detector, where each dot in the TRT represents a
“hit” registered in a straw tube as a charged track from the interaction
passes through the detector. The lines represent tracks reconstructed
from the hits, and the towers outside the TRT represent the energy
deposited in the calorimeter. The four straight lines moving out from
the TRT region are muons.
The second figure above shows the ATLAS Higgs signal from a
Higgs boson decaying to two photons. The TRT is also used to identify
photons, and since photons are neutral and thereby do not create
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u !
Duke PHYSICS
inner detector tracks, energy deposited in the electromagnetic calorimeter without a track in the TRT is considered a photon candidate.
Photons also frequently convert to an electron-positron pair en route
to the calorimeter, in which case a pair of nearby tracks can appear
somewhere in the tracking volume, rather than at the collision point.
The TRT is used to identify these “converted photon” track pairs,
which are also used in reconstructing Higgs candidates. Plotted is the
invariant mass distribution of two photons, and the small bump around
126 GeV is believed to be from the Higgs boson. The bottom plot
shows the mass distribution after subtracting the background curve. 1
GeV is approximately the mass of a proton. There are ~250 events in
the peak obtained from ~100 trillion proton-proton collisions. Together
with the CMS data, we can claim to have observed a new particle.
However, whether the particle has all the properties of the predicted
Higgs boson remains to be seen.
The TRT work is not our only contribution to the Higgs boson
discovery. Dr. Doug Benjamin worked on the computing infrastructure
for ATLAS, an essential ingredient to effectively carry out all analyses,
including the Higgs boson search. Professor Ayana Arce helped to
design the strategies used in the ATLAS experiment to filter potential
Higgs events from trillions of collisions. She has also helped write the
sophisticated simulations used not only in the Higgs search but also in
other physics analyses.
Some of us were involved with the Higgs search using the
Fermilab Tevatron Collider for some time prior to moving to the LHC
at CERN. Professor Mark Kruse, who once co-led the Higgs group
for one of the Fermilab experiments (CDF), has been working with
graduate student Kevin Finelli on more global searches that could be
sensitive to the Higgs boson. With the Tevatron data, Dr. Bodhitha
Jayatilaka currently leads the CDF search for Higgs bosons accompanying Z bosons. Professor Ashutosh Kotwal and his graduate student
Benjamin Cerio have developed a specialized method to search for the
Higgs boson decaying to two W bosons. Professor Al Goshaw and his
graduate student Mia Liu are searching for rare Higgs boson decays
that would test if it were the SM particle postulated by Peter Higgs.
Professor Seog Oh and Dr. Chiho Wang are looking for a way to use a
different final state to reconstruct the Higgs boson’s mass.
There are several undergraduate students at CERN involved with
various aspects of the Duke HEP group’s ATLAS research, including
the Higgs boson. They normally spend a summer at CERN supported by the University or the REU program. When they return, they
generally continue their research with a faculty mentor for one or two
more school years, with some of them writing a senior thesis on their
studies. This program provides students with firsthand experience in
programming, data analysis, and how big science actually works. The
picture below shows some of Duke students at CERN during the Higgs
announcement.
With twice as much data soon to come later this year, we may
have yet more evidence that this new particle is really the Higgs
boson. We look forward to finding what lies beyond the Standard
Model, as the model lacks components of gravity and dark matter and
suffers from what is called the “naturalness” problem. This is one area
where many in the Duke high energy physics group are also researching - looking for particles which can shed light on new physics. Any
discoveries of new physics will have far-reaching consequences, even
beyond that of the discovery of the Higgs boson. Stay tuned.
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u ! 15
Homing in on the Higgs Boson Mass
—by Ashutosh Kotwal
Prof. Kotwal’s research is in the area of particle physics, which has
made enormous strides in unravelling the workings of the subatomic world. The foundations were laid by the theory of quantum
mechanics and Einstein’s theory of relativity, both of which were developed a century ago. Quantum mechanics set up a new paradigm
to understand physics at small distances, and the theory of relativity revised our understanding of space and time and unified them
into a single fabric of space-time. These concepts, when merged
into a quantum field theory, were able to predict all the interactions
of matter and light. Building on this success, this framework was
expanded to incorporate theories of nuclear forces, quarks inside
the proton and the neutron, neutrinos and a host of other fundamental particles. All of these theories have been tested and proven
experimentally to an amazing level of precision.
Some important puzzles remain, however, and Prof. Kotwal is
investigating one of them which is at the heart of the reigning theory
of fundamental particles called the Standard Model. This theory
works in a very elegant way for mass-less particles. In fact, one of
its early successes as a quantum theory of light, radio-waves and
X-rays was precisely because electromagnetic radiation is described
by mass-less packets of energy called photons. But when applied to
one of the nuclear forces called the weak force, this theory ran into
trouble because the force-mediating particles called W bosons had
to be very massive. This observation could not be reconciled with the
theory, even though all other predictions have been proven correct.
Further studies of the weak force revealed that it had the curious
property of “parity violation”, which means that this force does not
act symmetrically with respect to its mirror image. The implication
was that even the mass of the electron could not be accomodated
into the theory without some modification. Considering that the
atom’s properties, and thereby almost everything about the world
around us, depend critically on the electron’s mass, we are clearly
missing an essential ingredient of nature.
The notion of a Higgs field permeating all space was introduced in the 1960’s to impart all fundamental particles their mass.
Proving or disproving the Higgs mechanism has been one of the
highest priorities of particle physics, and Prof. Kotwal’s research is
directly connected with solving the issue of the mass of fundamental particles. He has been pursuing the Higgs hypothesis in a number of ways, one of which is to make a very precise measurement
of the mass of the W boson. He has been making this measurement
for almost two decades, publishing world-leading results a number
of times with ever-increasing precision. Developing innovative concepts and techniques, he led his team to complete the analysis of
one million W boson events using the CDF experiment at the Fermi
National Accelerator Laboratory near Chicago.
Working with his postdoc Bodhitha Jayatilaka, graduate student Yu Zeng, and collaborators from Argonne National Laboratory,
Oxford Unversity, the Tri-University Meson Facility in Vancouver,
and University College London, his most recent measurement has
the unprecedented precision of 0.02%, one of the most precise
measurements in all of particle physics.
An energy disturbance propagating in the Higgs field will
be quantized in packets of energy, manifesting in our detectors
16 as particles we call the Higgs
boson. Knowing the mass of the
W boson very precisely can tell
us the mass of the Higgs boson.
According to the Heisenberg
Uncertainty principle, energy
does not have to be conserved over short intervals of time. The W
boson creates short-lived disturbances in the Higgs field, emitting
and absorbing Higgs bosons continuously. These “vacuum fluctuations” cause a small but calculable shift in the W boson mass, and
the amount of this shift depends on the Higgs mass. Prof. Kotwal’s most recent measurement, combined with these theoretical
calculations, predicts the Higgs boson mass to be 95±30 billion
electron-volts (GeV) in units of energy, almost the mass of a silver
atom. This result was featured on the cover of the prestigious
physics journal Physical Review Letters and chosen for a Synopsis
by the PRL Editor (http://physics.aps.org/synopsis-for/10.1103/
PhysRevLett.108.151803).
Prof. Kotwal has published this measurement at a very interesting juncture. The Large Hadron Collider (LHC) at the European
Particle Physics Laboratory, CERN in Geneva, Switzerland, has
been operating as the world’s highest energy particle accelerator.
Prof. Kotwal’s current research focus is the search for the Higgs
boson using the data from the ATLAS experiment at the LHC.
CERN has recently announced the discovery of a new particle
with a mass of 125 GeV, tantalizingly consistent with the predicted
range based on the W boson mass. If this particle is confirmed to
be the long-sought Higgs boson, it would provide a spectacular
confirmation of the Higgs hypothesis after 40 years. Prof. Kotwal
and his graduate student Benjamin Cerio are now measuring the
properties of this new particle at the LHC.
If the Higgs hypothesis is proven correct, other unanswered
questions still remain. Prof. Kotwal and his graduate student Chris
Pollard are using ATLAS data to search for new particles decaying
to top quarks. Such particles can help answer another big question: are there more than three dimensions of space?
The latest measurement
of the W boson mass
(vertical axis) and the
top quark mass (horizontal axis) with their
measurement uncertainties shown in the green
ellipse, superceding the
less precise previous
measurement of the W
mass (orange ellipse).
The white areas show
the allowed regions of
the Higgs boson mass
from direct searches.
The upper thin white band shows the mass of the newly discovered
particle at 125 GeV. The W boson mass, along with the top quark
mass, triangulates the mass of the Higgs boson in the Standard
Model.
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u !
Chinese-American Collaboration in Hadron Physics Bears Fruit
—by Mary-Russell Roberson
Prof. Gao and her former Ph.D. student Xin Qian, currently a Millikan
Fellow at Caltech. Xin gave an invited talk at this workshop.
Prof. Haiyan Gao, the new chair of Duke Physics, is working on several fronts to encourage collaboration among physicists in American and China—particularly among physicists who study hadrons,
particles that interact through the strong force. The time is ripe
because students and young scientists in China are jumping at the
chance to do research in the United States, and scientific funding
agencies in China—whose budgets are growing—are eager to
support international collaboration in physics. Just this year, the National Science Foundation of China awarded two grants to support
research being done at the Thomas Jefferson National Accelerator
Facility in Virginia by Gao and a team of 130 collaborators from 40
institutions and 8 countries—including China.
A paper describing some of that research was published in
Physical Review Letters August 10, 2011. Xin Qian, who earned his
PhD at Duke last year, is the lead author on the paper, which reports the results of an experiment exploring the three-dimensional
motion of quarks inside a neutron. Qian is currently a Millikan Fellow
at the California Institute of Technology. He is also the winner of the
2011 Jefferson Lab Thesis Prize. Gao, who was Qian’s advisor at
Duke, is also one of the authors of the paper.
While researchers at other laboratories have previously explored the three-dimensional motion of quarks inside protons, this
was the first time a team had looked at the motion of quarks inside
a neutron. The team used a helium-3 nucleus as the target for the
6 GeV electron beam. A polarized helium-3, which has two protons
and one neutron, is an effective polarized neutron target because
the spins of the two protons are opposite and “cancel” each other
out, leaving the spin of the lone neutron. The polarization is perpendicular to the plane formed by the beam and the electrons that
scatter off the target, and it can be arranged so that it is pointing
up or down.
When the electron beam hits the helium-3 nucleus, the virtual
photon exchanged between the electron and the target couples to
a quark inside directly. The struck quark combines with another
quark outside the nucleus to form a particle called a pion. By measuring the azimuthal angular distribution of such pions relative to
the plane of the electron, physicists can infer information about the
movement of the quarks inside the neutron before the beam hit.
The team of scientists plans to continue this line of research, with
some important improvements. The Jefferson Lab is undergoing
a major upgrade of the energy of the electron beam from 6GeV
to 12 GeV. Gao is leading a major effort to build a new $25-million
spectrometer that will take the advantage of higher electron beam
energies. The Jefferson Lab energy upgrade, which is funded by
the Department of Energy, is expected to be complete in 2013.
“We have a very good plan in place for the next decade for a
comprehensive major program at Jefferson Lab using 12 GeV and
the new spectrometer,” Gao says. “We’re also going to build a new
polarized proton target.”
In addition to encouraging U.S.-Chinese collaboration at
Jefferson Lab, Gao has also co-organized an annual workshop on
hadron physics in China for the past several years. Participants
are primarily from China and the U.S., but there are some from
Europe as well. The first workshop was in 2006, and it has been an
annual affair since 2009. The 2012 workshop is already planned
for Beijing. “Before this experimental program and the workshop,
the collaboration was on the informal side,” Gao says. The workshops allow physicists and representatives from funding agencies
to come together to plan more formal collaborations, such as the
research and the upgrade at Jefferson Lab.
Here at Duke, Gao was recently asked to be on the China
Faculty Council set up by the Provost’s office. Council members are
charged with facilitating research connections and new collaborations for faculty or units interested in working in China and/or
linking ongoing projects to China. Duke is building a campus near
Shanghai, which is where Gao grew up.
With all these projects underway, Gao says she sees a bright future for collaborative work among Chinese and American physicists.
Prof. Gao led an evening discussion during the 2011 US-China
Hadron Workshop in Weihai, China. Also in the photo are: Prof.
Fan Wang from Nanjing Uinversity, and Prof. Robert D. McKeown,
Deputy director of Jefferson Lab.
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u ! 17
Spotlight on Applied Physics
—compiled by Daniel Gauthier
One exciting aspect of conducting research in a university environment is the freedom to pursue a wide range of topics. Over the past
few decades, much of the research in the Department of Physics has
tended to be of a more fundamental nature, but many faculty are currently pursing applications of their fundamental work that has a high
likelihood of having “near-term” impact on technology and society.
Here, I give a snapshot of a few of the projects taking place in the
department that have an applied physics twist. I close by summarizing a possible PhD program in Applied Physics that is in the planning
stages in summer 2012.
Granular Materials: The behavior of granular materials is on the
one hand, a great challenge in terms of understanding the most basic
physics, and on the other hand, of great practical importance - the
cost of processing and handling granular materials in the US is as
much as $1 trillion per year. The Experimental Granular Group at
Duke, led by Prof. Robert Behringer, investigates both the fundamental
and applied aspects of granular materials, including jamming, friction,
and the effects of projectile impact. One project, involving collaboration with the International Fine Particle Research Institute, studies the
flow and jamming of granular materials under gravity such as that occurring in a hopper. The key experimental technique, pioneered here
at Duke, is to use 2D photoelastic techniques. Ph.D. student Junyao
Tang finds that this kind of flow is inherently stochastic, and has been
able to describe several of the mean and stochastic properties of
the material using relatively simply models that should be useful to
industrial scientists. On a different front, the group is studying friction in intermediate-scale granular materials. Surprisingly, the basic
nature of friction revealed in these human-scale experiments by Ph.D.
student (now post-doc) Peidong Yu also have implications for many
other systems that vary in scale from atomic nano-scale surfaces to
tectonic plates. Dr. Yu uses photoelastic disks to visualize the granular response during stick-slip events, where he observes a GutenbergRichter-like power law distribution of energy losses during slip events.
With Prof. Jackie Krim of NC State, he also pursued the granularnano-tectonics analogy. Another multi-institution project, lead by
Duke, is studying the granular dynamics of high speed impacts, with
relevance to such diverse phenomena as meteor impacts and ground
penetration of missiles. Using the photoelastic-disk approach and an
ultra-high-speed video system, Ph.D. student Abe Clark observes that
the force acting on an impacting object is highly stochastic due to the
generation, propagation, and damping of granular ‘force chains’ on
very fast time scales. He then relates this stochastic behavior to a
classical model of impact due to Poncelet.
Technologies for Gamma-ray Interrogation of Cargo: Professors
Ahmed, Weller and Wu are conducting research at the High Intensity
Gamma-ray Source (HIGS) that is important for developing gammaray-beam-based technologies with the capability of detecting and
identifying nuclear isotopes in large cargo containers. The features of
the gamma-ray beam at HIGS that enable this collaboration to lead the
world in this line of research are: (1) its high linear polarization, (2) its
high energy resolution and (3) its high intensity. Their work is providing new insights about photon-induced nuclear fission and is demonstrating the potential of using polarized photofission as a technique for
detecting the presence of fissionable isotopes in materials. The basic
concept is that every fissionable nucleus has a distinct angular pattern
18
Force chains in a hopper demonstrating Junyao Tang’s work.
of neutron emission for fission induced with linearly polarized photons.
The research has already revealed a measurable quantity that can be
used to distinguish fissile nuclei from other fissionable isotopes. The
team also involves students, scientists, and faculty from Duke, North
Carolina Central University (NCCU), the University of North Carolina
at Chapel Hill and Lawrence Livermore National Laboratory and is
funded by the Domestic Nuclear Detection Office at the Department
of Homeland Security.
Programmable self-assembly of metallic nanostructures:
Recently, Prof. Finkelstein’s group developed a novel method for
producing complex metallic nanostructures of programmable design.
They use “DNA origami,” which are artificial two-dimensional DNA
structures about 100 nm x 100 nm in size. The origami templates are
modified to incorporate uniquely coded single-strand DNA molecules
at predetermined locations. Small gold nanoparticles functionalized
with the complementary DNA sequence are then selectively attached
to these anchors. The seed nanoparticles are later enlarged, and even
fused, by electroless deposition of silver. Using this technique, they
have constructed a variety of metallic structures, including rings, parallel wires, etc. Their method opens a route for making more complex
metal structures for electronic and plasmonic applications.
Quantum Communication: The fundamental properties of quantum
mechanics appears to provide a new framework for performing computations on “hard” problems that scale much better on a so-called
quantum computer than on any classical computer and communications schemes that are provably secure based on physics principles
rather than relying on the fact that is hard to determine the prime
factors of large numbers. There are several faculty involved in developing key theories or technologies for quantum information science,
including Profs. Harold Baranger, Matthew Hastings, Jungsang Kim,
Daniel Gauthier, Maiken Mikkelsen, and David Smith. For example,
Gauthier is currently leading a large DARPA-funded consortium whose
goal is to develop a system for quantum key distribution, where many
classical bits of information are encoded on a single photon using
entanglement in a large-dimension Hilbert space.
Negative Differential Resistance: Prof. Stephen Teitsworth’s
research centers on aspects of nonlinear electronic transport in materials and devices that possess negative differential resistance (NDR),
where the electrical current flowing through the device decreases as
the applied voltage increases for certain values of applied voltage.
Such systems often exhibit bistability, which renders them sensitive to
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u !
intrinsic and extrinsic sources of noise. Specific systems of current
interest include semiconductor superlattices and tunnel diodes,
and related devices of technological importance such as quantum
cascade lasers. In a practical context, one generally wishes to
understand how to suppress instabilities that are often associated
with NDR. Experiments include novel approaches to measurement
of current switching dynamics over an exceptionally wide range of
time scales, as well as measurement of the power spectrum of noise
in the nonlinear regime. In parallel, Prof. Teitsworth’s group carries
out extensive modeling of these systems using state-of-art numerical
methods for nonlinear stochastic systems.
A degree program in Applied Physics: Over the past few years,
faculty in the Department of Physics and in other departments (many
of whom have PhDs in Physics), have seen growing student interest
in developing a graduate degree program with an applied physics
emphasis. Such a program will be highly interdisciplinary, crossing departmental and school boundaries. Given the current faculty
strengths on campus, a likely focus for such a program is in the general area of “Information Physics.” Information Physics refers to the
study of devices that transduce information between domains, process information on the classical or quantum levels, and for sensing
applications that give new ways of measuring our world. A proposal
for the degree program is being developed in Summer 2012.
Atomic
ForceM
Microscope
imageiof
DNA origami
gold nanoparticle
Atomic Force icroscope mage of D- NA origami assemblies. (250 nm scale bar)
-­ gold nanoparticle assemblies. (250 nm scale J. Krim, Peidong Yu, and R. P. Behringer, Pure and Appl. Geophys. 168, 2259 (2011).
J.M. Mueller et al., Phys.Rev. C 85, 014605 (2012).
bar) M. Pilo-Pais, S. Goldberg, E. Samano, T. H. LaBean, and G. Finkelstein, Nano Lett. 11, 3489 (2011).
H. Xu and S.W. Teitsworth, Appl. Phys. Lett. 96, 022101 (2010).
Perspective on “Jamming by Shear”
— Submitted by Robert P. Behringer
In a December, 20011 Nature paper (Nature 480, 355 (2011)), Dapeng
(Max) Bi, Jie Zhang, Bulbul Chakraborty and Bob Behringer reported
novel results for jamming of granular materials. Briefly, this work, Jamming by Shear, showed that systems of frictional grains form ordered
jammed states, where the order is associated with anisotropy in both
force and contact networks. These states can be fragile or they can
be jammed. Max is a graduate student, working with theorist Bulbul
Chakraborty at Brandeis University. Then Post-doc Jie Zhang and Bob
Behringer performed the experiments at Duke. Jie is now Assistant
Professor at SJTU in Shanhai.
Before describing these results in more detail, it is useful to
review the setting of this work, which involves jamming, connections
to glassy behavior, and a novel effect discovered by Osborne Reynolds,
the eminent pioneer of fluid mechanics. Towards the end of his career,
Reynolds was very interested in granular materials. In a now historic
experiment, he showed that when granular systems are sheared, they
tend to expend, an effect now called Reynolds dilatancy. Jamming
occurs for systems of particles whose density is high enough that the
system can stably support stresses. All sorts of particulate systems
jam, including granular materials, foams, colloids and molecular systems. Clearly, if a stress is applied to a system with too low a density,
it will respond in a fluid-like way; but if it is sufficiently compact, it will
respond as a solid. In the conventional picture of molecular systems,
increasing density leads to a transition from a fluid to a crystalline
solid. For jamming, there is a major difference: the system does not or
cannot form a crystal. Density is only one of several important quantities that control jamming: temperature is important for some systems
(e.g. molecular systems, and in some cases, colloidal systems). In
addition, if a jammed system is subjected to shear stresses, it can also
deform irreversibly, effectively unjamming the system If a molecular
system, for instance water, is cooled rapidly, it can be in a glassy
state, i.e. one in which it is out of thermal equilibrium, and so viscous
that the time to observe any response to shear is extremely large.
Unlike molecular (or other) systems for which temperature is relevant,
granular materials are typically always in a zero-temperature state. To
appreciate why, it suffices to note that kBT is miniscule compared to
the energies needed to affect even one grain.
Much of the discussion about jammed particulate systems of
any type was brought to the fore by a proposal by Andrea Liu and
Sid Nagel (Nature, 1998) that there is a universal ‘phase’ diagram for
jammed systems such that for any system, there exists a region in a
state space of temperature, T, density (often expressed in terms of
the packing fraction, φ), and shear stress, τ, for low enough T, high
enough φ, and low enough τ, that the system is jammed. The idea of
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u ! 19
this proposal was that all systems would have similar jamming diagrams, and similar behavior in the vicinity of jamming—i.e. universal
behavior. The idea of universal behavior is particularly appealing to
physicists, and this paper stimulated an enormous amount of activity,
mostly in terms of theory or simulations, and to a lesser extent in
terms of experiments. In fact the Liu-Nagle paper was inspired in part
by a paper by Cates et al. in Physical Review Letters (1998), highlighting what they termed fragile states for particulate matter. Such
states could be achieved for particulate systems that had been highly
sheared, so that they system had developed resistance to further
shear in the same direction, but also such that there was negligible
resistance to a reversal of the shear. The idea was that shear applied
to particulate structures engendered ‘force chains’, i.e. roughly linear
chains of particles that supported the applied shear stress in the
‘compressive’ direction of shear. (It’s worth noting that shear strain
consists of compression in one direction, with matched expansion in
the other direction, all the while keeping the system size fixed.) For
reasons of simplicity, much of the theoretical modeling of systems
near jamming was carried out for frictionless particles. Then behavior
for jamming is thought to be relatively simple and clean: There is
a single lowest density φJ , such that any frictionless system below
that density is unjammed, and that states above that density are
jammed, unless they are subject to such strong shear stresses, that
the system is forced to ‘fail’, and hence to flow (be unjammed) under
continued shear stress.
The paper of Bi et al. was preceded by two others that set the
stage experimentally. Trushant Majmudar and Bob Behringer first
showed in 2005 (Nature) that it is possible to use a special photoelastic technique to make highly quantitative measurements at the grain
scale for systems of disks—a kind of two-dimensional granular material. This meant that it was possible, for the first time, to obtain the
kind of force information that theoretical (e.g. molecular dynamics)
simulations produce. In that paper, Majmudar and Behringer showed
that the statistical properties of sheared and compressed (i.e. isotropic) states are qualitatively and quantitatively different. With two additional collaborators, Matthias Sperl and Stefan Luding, they showed
two years later (Phys. Rev. Lett. 2007) that under isotropic conditions,
the jamming properties of frictional photoelastic disks are similar,
though not quite identical, to the predictions for frictionless disks. (It
is interesting to note that some of these path-breaking simulations
involved Corey O’Hern, who as an undergraduate at Duke carried out
granular experiments, before obtaining his Ph.D. in theoretical physics
at Yale, and working with Liu and Nagel on simulations.)
Still, the issue of what happens to physical granular systems
when they are sheared near jamming was a puzzle. It was this issue
that was tackled in the Bi et al. paper. The results were striking on
several accounts. The most basic observation from these studies is
that it is possible to create stress-free (e.g. unjammed) states below
a nominal φJ , then to shear the system to produce first a fragile and
then a jammed state, able to resist stresses in all directions. This is
related to Reynolds dilatancy, although Reynolds always had systems
that were jammed. The Bi et al. states require a ‘phase diagram’ that
is substantively different from that proposed in the Liu-Nagel picture
which had been validated for systems of frictionless particles. It
appeared that friction is essential for creating and stabilizing the
fragile and shear jammed states, and that there is no analogue in the
theoretically studied systems of frictionless particles. (This picture
20
may change, as simulators probe more intensively for shear jamming for frictionless particles.) In addition, the states observed by
Bi et al. had novel structural properties. First ‘force chains’ formed
in the compressive direction of the shear, leading to a novel kind of
unidirectional percolation, and then with more shear, networks of
chains percolated in all directions, as in the picture below, showing a
photoelastic image from Jie’s experiments. These networks of force
chains are linked to the formation of stresses, both a shear stress and
a pressure. It is possible to make an analogy to the networks of force
chains to a magnetic (or perhaps better, nematic crystal) system.
The idea is that shear creates a directional order that is analogous to
these other better known systems. Ordering by shear occurs in the
shear jammed regime . A final feature of some interest is that all data
for shear stress, pressure, and other variables of interest could be
reduced to a universal form by considering the fraction of ‘jammed’ or
(as they are known, non-rattler) particles.
Work has continued apace since the appearance of the Bi et al.
paper. Ph.D. student Jie Ren and post-doc Joshua Dijksman have,
among other things, focused on the evolution of the forces within a
granular system, in the shear jamming regime, that is sheared over
and over again—so-called cyclic shear. They find very slow (logarithmically slow) relaxation that is suggestive of an activated process in
a new kind of statistical mechanics known as the stress ensemble.
Their data shows completely unexpected scaling behavior, where the
amplitude of shearing behaves like a temperature, and where φJ is a
singular point. Like many interesting scientific issues, studies such as
these continue to reveal both insight and new, fascinating questions.
There is more to come, so please stay tuned. The implications of this
and other work on jamming are highly relevant to a range of disordered particulate systems, both in terms of their static and dynamics
properties.
Photoelastic photograph from the experiments of Jie Zhang and Bob
Behringer, showing a shear jammed state. Roughly, the brighter a
particle appears, the larger the force it is carrying. Note that there
are chains of particles that carry large forces (and appear bright
here). The preponderance of these force chains are in the horizontal
direction, that is the system is anisotropic.
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u !
Electron Neutrino Appearance
in the T2K Experiment —by Kate Scholberg and Christopher Walter
In June 2011, the T2K experiment in Japan announced indications that muon neutrinos were transforming
into electron neutrinos. Since that time, even more data have strengthened the result. Using a powerful
accelerator north of Tokyo, a neutrino beam was directed to the Super-Kamiokande detector 183 miles
away under the Japanese Alps in western Japan. The neutrinos were measured near where they were
born and then again at Super-K. An analysis showed that a tiny number of the neutrinos that started north
of Tokyo as muon neutrinos transformed into electron neutrinos before being detected in Super-K. This
result, which is actually just the beginning of the experiment’s explorations of neutrino physics, capped
over 10 years of preparations by hundreds of people including the neutrino group at Duke.
This August, the work was published in Physical Review Letters along with a viewpoint article you
can read here: http://physics.aps.org/articles/v4/57 . Later the Physics World magazine chose the
result as one of the top ten physics breakthroughs of 2011 ( http://physicsworld.com/cws/article/
news/48126 ). The result from T2K was the first of five measurements of the so called “Theta 13”
Duke postdocs and graduate
mixing angle. In a remarkable year starting with the T2K results and culminating with an announcestudents working on Super-K
ment from a nuclear reactor experiment in China called the “Daya Bay Experiment”, the value of this
during the upgrade for T2K.
parameter was shown to be non-zero and then precisely measured. This surprising result (it was widely
believed the value was likely much smaller than it wound up being) has revolutionized the entire neutrino physics field. Now everyone is concentrating on trying to measure the remaining neutrino properties which large values of the angle make it possible to determine. Eventually, it is
hoped that this research will lead to an understanding of why there is more matter than anti-matter in the universe.
Duke physicists play important roles in the running and analysis of the T2K experiment. Duke faculty Kate Scholberg and Chris Walter
lead a team of postdocs and graduate students on the project and have leadership roles in the overall experiment as well. Their work is based
at the Super-K detector and they have worked on maintaining, building and running it for almost 15 years. Graduate student Josh Albert’s Ph.D.
thesis documented the oscillation analysis which led to this result. Josh graduated with a Ph.D. in May and started a postdoctoral position
working on the EXO neutrinoless double beta decay experiment. Graduate student Taritree Wongjirad is an expert on the outer part of the
Super-K detector used to make the sample pure, and postdoc Roger Wendell (who just became a faculty member at the University of Tokyo) is
based in Japan and plays a key role in the experimental operations of Super-K.
T2K was interrupted by one year due to the 2012 great Japan earthquake. Now operations have restarted and the entire Duke team
including new postdocs Tarek Akiri and Alex Himmel are excited to see what we find out next.
KamLAND-Zen Started Zero-Neutrino Double-Beta Decay Search
—by Werner Tornow
After discovering reactor neutrino oscillations, determining the heat produced by radioactive decays
in the interior of the Earth, determining the extraterrestrial high-energy anti-neutrino flux on Earth, and
studying solar neutrinos with the KamLAND detector, on October 12, 2011 a subgroup of the original
Japanese-US KamLAND collaboration commenced its search for the zero-neutrino double-beta decay of
136Xe. For this purpose, a 3.4 m diameter nylon balloon filled with about 400 kg of 136Xe absorbed in
scintillator fluid and viewed by about 2000 phototubes was immersed in September into the original 1
kilo-ton KamLAND liquid scintillator detector (see Figure).
Discovering zero-neutrino double-beta decay would allow the determination of the electron neutrino mass (known to be below about 300 meV) and would prove whether neutrinos are Dirac particles
or Majorana particles, i.e., whether they are identical to their anti-particles.
The KamLAND detector is located in the Kamioka mine in the Japanese Alpes in the cave vacated
by the Kamiokande collaboration once Super-Kamiokande became operational. A TUNL group, under
Prof. Werner Tornow’s leadership, has built the outer detector (also called veto detector) of KamLAND
in the years 1999 – 2001.
Even before then, Werner Tornow, together with Ludwig De Braeckeleer (at that time at Duke) and
Giorgio Gratta from Stanford were responsible for the double-beta decay section of the original USKamLAND proposal.
KamLAND Zen balloon
Werner Tornow, now a Professor Emeritus, was on a week-long KamLAND remote shift (i.e., monitoring the experiment remotely from his office during the Japanese night) just before the official start of
this double beta-decay search. This new important phase of Kamland is called “KamLAND-Zen” . After two years of running, the collaboration
hopes to reach a sensitivity to the neutrino mass of 80 meV.
Future plans for after 2013 call for increasing the 136Xe mass to 1000 kg and for replacing the liquid scintillator fluid with a “brighter”
scintillator which provides a better energy resolution. This will help to distinguish the tail of the abundant two-neutrino double-beta decay
energy spectrum from the potential zero-neutrino events of interest.
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u ! 21
Outreach
TUNL Outreach
Activities Update
— by Calvin Howell
The Triangle Universities Nuclear Laboratory
(TUNL) is involved with activities associated with
the Nuclear Science Merit Badge of the Boy
Scouts of America. As part of this outreach to
young people, TUNL offers science presentations,
hands-on activities and tours of the research facilities that are appropriate for a wide age range (7th
grade through high school students).
Last fall (September 10, 2011) Boy Scout
Troop 101 from Asheville, NC visited TUNL as
part of their activities toward obtaining a Nuclear
Science Merit Badge. The troop leaders were Jeff
Cole, Ruth Johnson, Tony Johnson and Cissy Williams. Tony Johnson is a Duke graduate (class of
1987) and an Iron Duke. The scout’s visit to Duke
was facilitated by Sally Schatz of the Duke AthletGroup from Boy Scout Troop 101 of Asheville, NC with Chris Westerfeldt in the
ics Department.
lobby of the DFELL/HIGS facility.
Their visit to TUNL was coupled with their attending the Duke
vs. Stanford football game. The group consisted of nine scouts of
ments that we carried out in the Tandem Laboratory. One measureages from about 12 to 16 years old. The scouts arrived around 9
ment demonstrated the relationship between radiation intensity
am. Chris Westerfeldt and Prof. Calvin Howell gave presentations.
and distance from a nearly point source. The second measurement
Howell’s presentation was a general overview of nuclear matter and
illustrated the difference in the effectiveness of different types of
nuclear binding in the context of the other natural forces. Howell told
the scouts that nuclear binding energy is about a million times greater materials to shield against gamma-ray radiation. The material studies
were plastic, aluminum, iron and lead. TUNL graduate students David
than chemical binding, that the diameter of the nucleus, which is at
Ticehurst (UNC) and Dustin Combs (NC State) assisted the scouts
the core of the atom, is about ten thousand times smaller than the
diameter of the atom and that stars are powered by nuclear reactions with the measurements.
that release the tremendous amount of energy stored in the nucleus.
He asked them to imagine sitting in the stands at the football stadium
and a fly lands in the middle of the field. The relative size of the fly
to the field is about the same as that of the nucleus of the atom. In
continuing this analogy with the fly as the nucleus and the spectators
as the electrons in an atom, he said that the fly would weigh about
2,000 times more than the people in the stands. Howell’s presentation
also included a brief history of the advancement of knowledge about
the subatomic world by making note of the contributions of some of
the key people, e.g., Henri Becquerel, Marie and Pierre Curie, Ernest
Rutherford, Lise Meitner, Enrico Fermi and Hans Bethe. Chris Westerfeldt’s presentation included descriptions of the types of radiation,
how radiation interacts with matter, typical radiation exposure rates
and how we might reduce our exposure to radiation. The discussion of
radon in his presentation was a big hit with the scouts. Several scouts
inquired how they might obtain radon testing kits.
After the presentations the scouts toured the DFELL/HIGS facility Chris Westerfeldt presenting the types and levels of radiation occurring
and the Tandem Laboratory. The scouts participated in two measure- naturally in the environment.
22
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u !
Duke PHYSICS
Ten Years Under the Stars
— by Ronen Plesser
The Duke Teaching Observatory was established in the fall of 2002
with funds from Arts and Sciences and the Physics Department. The
Observatory is located in a clearing in the Duke Forest about 4.5
miles from West Campus.
The observatory is an important part of the student experience
in Physics 55 (Introductory Astronomy). Students visit the observatory three times each over the course of the semester, allowing
small group work in which 3-4 students operate a telescope. Over
the course of the term, students progress from simple observation
tasks to independent design and implementation of more advanced
observations. The observational component is frequently cited by
students as their favorite part of the class and an important component in their learning.
The observatory is also used for science outreach activities.
The observatory is open to the general public for regularly scheduled Open House events, usually on Friday or Saturday evenings or
set to coincide with astronomical events of interest such as eclipses
or meteor showers. At the Open Houses 1-3 telescopes are set up
and aimed at the most striking objects visible. While visitors view
these in turn, Prof. Ronen Plesser conducts a discussion of the
astrophysics of the objects being viewed. In response to questions,
this often ranges to topics from Big Bang cosmology to Greek
Mythology. Open House typically lasts about 2 hours. In addition to
these public events, various groups schedule visits to the observatory. These include class trips by local schools and campus groups
which are conducted much the same way as Open House, except
that teachers bringing their students out are encouraged to take
part in selecting targets and in the associated discussions.
On occasion, the telescopes are even transported to other
locations for outreach events. In the fall, one telescope is used by
Physics 217 (Advanced Undergraduate Lab) students to measure the
rotation of the Sun, an experiment designed by Dr. Bill Ebenstein,
who has also done wonders over the years in maintaining the sensitive devices through this tough regimen of use as well as devising
helpful improvements. We have plans to expand the scope of the
program at the observatory to include astrophotography and wheelchair access to the telescopes. To hear more about these ideas
contact Ronen Plesser at plesser@cgtp.duke.edu.
Upcoming open houses are usually announced here in the enewsletter, the Duke Events calendar, on the observatory web page
and on the Duke Physics‚ Facebook page. So stay tuned and we
hope to see you under the stars!
See past news about the observatory “The Science of Stargazing” at: http://news.phy.duke.edu/2010/12/prof-ronen-plesser-induke-magazine/.
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u ! 23
News
President Brodhead
Visits the Behringer Lab
— by Robert P. Behringer
On February 4, 2012, Duke University President Richard Brodhead visited the Physics
Department and in particular, explored the mysteries of granular materials. He began his
visit by trying a simple granular experiment on his own, with a little help from Prof. Bob
Behringer.
Jie Ren, a Ph.D. student, showed President Brodhead how her experiment works.
She and post-doc Joshua Dijksman are studying the basic statistical physics of shear
granular material. Along the way President Brodhead asked a number of questions that
showed his quick grasp of the physics!
He then learned about Duke Physics’ ‘earthquake machine.’ This experiment probes
the same kind of stick-slip that occurs in earthquake fault zones like the San Andreas, with
the advantage that the experimenter can see exactly what is happening, and of course the
energy released is not so dangerous.
At President Brodhead’s last stop, graduate student Abe Clark showed off his apparatus
that is used to probe the way a meteor behaves when it strikes the earth. In this picture,
from left to right: President Brodhead, holding a polarizer, Prof. Haiyan Gao, Chair Department of Physics, Hu Zheng, visiting scholar, and Ph.D. students Jie Ren, Somayeh Farhadi
and Abe Clark.
View more photos on Flickr at: http://www.flickr.com/photos/dukephysics/.
Photo by Cristin Paul
Photo by Cristin Paul
The Department Celebrates the
New Hertha Sponer Biography
— by Horst Meyer
On April 5, 2012, the Department of Physics celebrated the unveiling
of the English version of Prof. Hertha Sponer’s biography, which is now
available both as an e-book and as paperback and hardback. The wellattended event included introductory remarks by Dean Robert Calderbank, Dean Laurie Patton and Vice Provost Nancy Allen.
l-r: Prof. Daniel Gauthier, Dr. Morris,
After these remarks, Dr. Marie-Ann Maushart, the author of the origiProf. Winnewisser, Dr. Maushart, and Prof. Horst Meyer
nal biography, described the process by which she selected this project
for her PhD dissertation, the difficulties she faced in convincing her mentor to support it, and the research process for uncovering information
about Prof. Sponer. Dr. Maushart was followed by Prof. Brenda Winnewisser, the principal organizer and editor of the English translation, who
described her own interest in the history of Prof. Sponer and her thoughts of her time in the Department of Physics around the time of Prof.
Sponer’s retirement. Next, Dr. Ralph Morris, the English translator, described how he was contacted by Prof. Winnewisser, how he managed to
undertake the translation while fully employed, and how he enjoyed learning some of Prof. Sponer’s science during the process. These stories
were followed by a lively discussion of Prof. Sponer, her life at Duke, and the difficulties women faced and continue to face in the sciences.
There were also several comments about the fact that Prof. Sponer left a long written legacy of her life and work, as well as the difficulty
historians might have in the future documenting the activities of current scientists, given the possible transitory nature of digital records. After
the presentation, the speakers were taken to the Chair’s Conference Room in Department of Physics to view the portrait of Prof. Sponer by
Marianne Manasse (ca. 1948).
Both Profs. Daniel Gauthier and Horst Meyer were significantly involved in making possible the English version of the biography.
24
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u !
Taishan College Students
Coming to Duke Physics
— by Haiyan Gao
Duke University and Shangdong University (SDU) signed a fiveyear agreement in May 2012 to have five students annually
from Taishan College at Shandong University to come to Duke
Physics for their junior year.
Shandong University (SDU) http://www.sdu.edu.cn/
english/ is located in the city of Jinan, capital of Shandong
province, about halfway between Beijing and Shanghai on
the high-speed railway connecting the two cities. Jinan is
a couple of hours car ride from where Confucius was born,
and has a renowned liberal arts program in China. Its science
program is also well known in China, particularly in the areas
of mathematics and also in physics.
Shandong University is one of the top universities in China. Students from Taishan College are highly selective - SDU admits more than
10,000 students every year, but admits only 70 to the Taishan College, an honors college for students in natural sciences. Among the first
group of Taishan College students coming to Duke in August, 2012, they are from left to right in the above photo: Xiaojun Yao (姚晓骏), Yajing
Huang (黄雅靖), Xiaomeng Jia (贾晓萌), Xiaqing Li (李夏卿), Yuchen Zhao (赵雨辰).
This new Duke-SDU program will help foster long-term collaborations with universities in China at many levels starting from student
exchange. This program will also enrich the experience of Duke physics students and faculty and provide great opportunities for these
talented Chinese students. In the longer term, we hope to create opportunities for Duke students, who are interested in studying and doing
research in China as part of the study abroad program, and for faculty who are interested in collaborations with colleagues in China. DukeKunshan University (DKU) in China can be an important resource to help achieve this goal. Students from this program will be supported by
scholarships from Duke, Ministry of Education of China, and Shandong University (prepared by Prof. Haiyan Gao, photo by Hongxiao Song).
山东大学“泰山学堂”是为实施中国教育部“基础学科拔尖学生培养试验计划”
、加速推进拔尖创新人才培养工作而设立的。
“泰山学堂”依托数学、物理学、化
学、生物学、计算机科学等5个基础学科，创新培养模式，为学生制定个性化培养方案，加强研究性和研讨式教学，旨在培养基础扎实、学风朴实，有德性、富有创
新精神和创新能力的拔尖人才。泰山学堂一直致力于为学生创造海外学习机会，丰富其海外经历。2011年下半年，山东大学物理学院与美国杜克大学物理系达成
协议，杜克大学物理系从2012年开始每年将接收5名泰山学堂物理取向学生，进行为期一年的访学。
杜克大学是一所著名的国际化研究型大学，教育和科研实力世界领先。该校物理系师资力量雄厚，研究方向广泛，覆盖了凝聚态物理、粒子物理与原子核物
理、量子光学、生物物理以及加速器物理学等领域。杜克大学物理系尤其注重培养学生参与科研实践的能力，学生将在访学期间参加杜克大学的科研活动，培
养协同创新能力。本合作项目拟选派专业为山东大学泰山学堂物理取向，计划每年选派5名三年级学生于8月赴杜克大学进行一学年专业课程学习，次年5月学习结
束。学习采取插班学习的形式，由杜克大学和山东大学共同确定课程。鼓励学生在学习结束后，在杜克大学进入科研实验室进行三个月的暑期研究。留学结束后，
杜克大学将给予相应学分，并对每名学生的学习、交流、科研等方面进行书面的综合评价。
本项目由泰山学堂总体管理，物理学院与泰山学堂共同设立项目管理领导小组，负责项目国内部分的管理。学生选拔采用平时综合成绩结合多轮面试的方
式，综合考察学生的考试成绩、日常表现、科研思维、英语交流等多方面情况，杜克大学积极参与共同选拔出最优秀的学生赴美交流。学生派出后，由杜克大学负
责日常的管理。杜克大学为合作项目的学生以奖学金方式减免了大部分学杂费，山东大学负担学生其余的学费和在校住宿和伙食费用，其他个人生活和学习费用
与国际旅费由学生承担。山东大学为学生争取国家留学基金委的经费支持，尽量减轻学生的负担。
该项目的实施可以使学生们在国际一流大学中学习、科研和生活，感受不同文化的差异与交流，激发与加强从事基础科研的兴趣与热情，真正成为国际化的拔尖
人才。另一方面，泰山学堂可以积累经验，探
索与国际一流大学协同培养拔尖人才的创
新机制，深化与拓宽合作领域，加强自身人
才培养方面的建设，促进将山东大学建成国
际一流大学目标的实现。
杜克大学物理系主任高海燕教授与泰
山学堂物理取向的学生座谈 （2011.12）
(本文由山东大学物理学院王萌教授提供，
经杜克大学高海燕教授修改。摄影：山东大
学物理学院宋洪晓)
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u ! 25
TUNL/HEP REU Students:
Summer 2012
— by Ayana Arce, Calvin Howell and Crystal Royal (June 2012)
Fourteen undergraduate students from institutions around the country
have recently arrived on campus to participate in the TUNL and Duke
Research Experience for Undergraduates (REU) program in nuclear and
particle physics. Most of the students are rising seniors and are interested in attending graduate school in physics or a closely related area.
During this 10-week long program, which runs from May 29th until August
5th this year, the students will conduct research in nuclear and high-energy physics. Each student is assigned a project associated with ongoing research in nuclear or particle physics and works directly with faculty,
graduate students and postdocs from the TUNL consortium universities (Duke University, North Carolina State University and the University of
North Carolina at Chapel Hill). As part of their involvement in research, the students attend lectures that provide introductions to concepts in
nuclear and particle physics and to experimental techniques and instrumentation used in these fields. In addition, the program includes a seminar series that exposes the students to questions and technologies used at the research frontier of the fields. Social activities are organized
and encouraged as a means of establishing a sense of community among the REU students and comradery among the students and members
of their assigned group. The students will tour the physics departments of the three consortium universities to get a glimpse of the research
activities beyond nuclear and particle physics and to meet faculty in each department.
Sponsored by the National Science Foundation, the REU program at TUNL has involved students in low-energy experimental nuclear physics
research each summer since 2000. Through partnership with the Duke High-Energy Physics (HEP) group, an international component has been
added to the program. This year four students have been selected to work in Geneva, Switzerland at the Large Hadron Collider at CERN with the
nuclear theory group on high-temperature and high-density physics and with experimentalists in the Duke HEP group. These students will spend
the last 5-weeks of the 10-week program at CERN.
Row 1 (L to R): Wolfe Greene (Univ. Evansville), Olivia Miller (East Tenn. State Univ.), Anna Hughes (RPI), Irene Zawisza (Moravian Coll.), Ashley Huff (FSU),
Barbara Fisher (Richard Stockton Coll.)
Row 2 (L to R): Neal Anderson (Univ. MI), Peter Koufalis (Kutztown Univ.), Joshua Bradt (Univ. Rochester), Nikki Sanford (High Point Univ.)
Row 3 (L to R): Ronald Malone (Gettysburg Coll.), Anthony Charles (UVA), Quesly Daniel (Florida A&M Univ.), Nathan Tripp (Grand Valley State Univ.)
26
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u !
Staff Highlight
Two Great Places for Making Just About Anything: The Duke
Physics Instrument Shop and the Staff Machine Shop
— by Mary-Russell Roberson
Richard Nappi in the Staff Machine Shop
When in need of a custom-designed tissue press, a mouse-exposure
chamber, an umbilical cord blood collector, photoelastic disks, or almost any other apparatus made of metal or plastic, those in the know
turn to the Duke Physics Instrument Shop. “We do all types of plastic
and metals works,” says manager Bernie Jelinek. “We do welding,
brazing, silver soldering, and a little bit of sheet metal. We do all types
of machining—milling, turning, grinding.”
The Instrument Shop, located on the bottom floor of the physics
building, is stocked with dozens of machines including three computer
numerical controlled (CNC) 4-axis mills and a CNC lathe. Its services
are available to anyone in the Duke community, local nonprofits, and
others for a fee of is $63.25 per hour to design, build, and repair
tools and equipment. In addition to Jelinek, the Instrument Shop is
staffed by senior instrument makers Bill Peterson and Phil Lewis.
One satisfied customer is Jonathan Boreyko, a fifth-year PhD student
in the Department of Mechanical Engineering and Materials Science.
“I have published several papers that used an experimental system
entirely fabricated by the Physics Shop,” he says. His most recent
work required the fabrication of dozens of different copper plates,
one of which needed to be resurfaced about once a week. “Bernie and
the staff were always happy to do this for me immediately, even when
I walked in without advance notice,” he says. “It is safe to say that I
would not have been able to create my last few experimental setups
without the Physics Shop.”
For people who want to do the work themselves, another option
is right next door: the Staff Machine Shop. In order to use the selfservice Staff Machine Shop, participants must first complete a course
to learn how to use the equipment, which includes drill presses,
milling machines, lathes, bandsaws and more. The course is taught by
the shop manager, Richard Nappi, who says, “Modeling and designing
parts and assemblies on the computer is all well and good, but I think
there’s something to be said for knowing how to use a screwdriver
and a hammer and wrenches. It helps people get an idea of how
things are actually put together.”
As a final project, participants in his class make a c-clamp. Then
their DukeCard is activated so they can access the shop. Nappi is usually
on hand to answer questions and make sure people are working safely.
Second-year physics graduate student Bonnie Schmittberger
took the class in July 2010. “It was really fun,” she says. “It was nice
to be able to get my hands dirty and build things I knew I was going
to be able to use in broad applications in the lab.” She says she uses
the shop often to make all kinds of things, from simple objects like
mounts to more complex items whose measurements need to be
extremely precise. For experiments in Prof. Dan Gauthier’s lab, she
repaired a portion of a laser head that uses water to cool off a crystal
that tends to overheat. The nozzle she made needs to fit perfectly
because even a tiny leak would ruin the laser head. “Whenever I have
a question about anything I need for the lab I go to Richard,” Schmittberger says. “He’s always very helpful.”
Nappi enjoys helping people solve problems and design tools
for specific uses. In one case, researchers showed him a 22-second
video of a piece of equipment that had been made by scientists in
China and he worked with them to figure out how to make one like it.
Nappi keeps a list of people who are interested in the shop class,
which takes a total of 24 class hours to complete. After he’s got
four people confirmed, they decide together on a schedule for class
meetings. The class is free for people in the physics department. For
others in the Duke community, the class costs $600, and there is a
fee of $150 per year to have access to the shop. For the most part,
people must pay for their own materials, although Nappi will help
locate materials and order them. He says 70 to 75 people use the
shop over the course of a year, including not only physicists, but also
people from the Medical Center and the departments of Biomedical
Engineering, Electrical and Computer Engineering, and Chemistry.
See more photos at: http://www.flickr.com/photos/dukephysics/
sets/72157628235087107/.
S i g n u p f o r o u r e - n e w s l e t t e r a t h t t p : // n e w s . p h y . d u k e . e d u ! 27
Department of Physics
Duke University
Box 90305
Durham, NC 27708-0305
Standard
US Postage
PAID
Durham, NC
Permit No. 60
Photo by Anyi Li