Symposium: “Condensed Matter Physics and Optics” Monday

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Symposium: “Condensed Matter Physics and Optics”
Monday, December 20th, 2010
Program:
09.15
Welcome
Thomas A. Henzinger (President IST Austria)
09.20
Seeing electrons in one and two dimensions: optics of
carbon nanotubes and graphene
Tony F. Heinz (Columbia University, Departments of Physics
and Electrical Engineering)
10.00
Quantum optics and mesoscopic physics
Atac Imamoglu (ETH Zurich, Quantum Photonics Group)
10.40
Graphene: CERN on the desk
Mikhail I. Katsnelson (Radboud University of Nijmegen,
Institute for Molecules and Materials)
11.20
Coffee break
11.40
A single molecule approach towards biological pattern
formation
Petra Schwille (Technical University Dresden, Biophysics)
12.20
Bone: A fascinating material
Steve Weiner (Weizmann Institute of Science, Department of
Structural Biology)
13.00
Lunch
Location: Seminar Room Mondi 2 (Central Building)
Institute of Science and Technology Austria | Am Campus 1 | 3400 Klosterneuburg
Symposium: “Condensed Matter Physics and Optics”
Abstracts:
Time: 9.20
Seeing electrons in one and two dimensions: optics of carbon nanotubes and
graphene
Tony F. Heinz (Departments of Physics and Electrical Engineering, Columbia University)
Two of the most fascinating nanoscale materials to have emerged over the past several
years are based on the sp2-hybridized single layers of carbon: The one-dimensional
system of carbon nanotubes and the two-dimensional system of graphene. In addition to
the remarkable mechanical and electronic characteristics of these materials, their optical
properties are of great interest and importance for fundamental science of low dimensional
materials, for metrology, and for emerging photonic applications. We will discuss the
nature of the excited states in these distinctive systems, how they are reflected in the
optical properties of the materials, and how they can be measured experimentally.
Time: 10.00
Quantum optics and mesoscopic physics
Atac Imamoglu (ETH Zurich, Quantum Photonics Group)
Spins confined in semiconductor quantum dots offer new possibilities for realizing
quantum optical systems with unique properties. Conversely, optical measurement
techniques provide a powerful tool for studying mesoscopic condensed-matter systems.
Specific recent experiments I will discuss include the observation of photon blockade and
the optical signatures of the Kondo effect.
Institute of Science and Technology Austria | Am Campus 1 | 3400 Klosterneuburg
Symposium: “Condensed Matter Physics and Optics”
Time: 10.40
Graphene: CERN on the desk
Mikhail Katsnelson (Radboud University of Nijmegen, Institute for Molecules and
Materials)
Graphene, a recently (2004) discovered two-dimensional allotrope of carbon (this
discovery was awarded by Nobel Prize in physics 2010), has initiated a huge activity in
physics, chemistry and materials science, mainly, for three reasons. First, a peculiar
character of charge carriers in this material makes it a “CERN on the desk” allowing us to
simulate subtle and hardly achievable effects of high energy physics. Second, it is the
simplest possible membrane, an ideal testbed for statistical physics in two dimensions.
Last not least, being the first truly two-dimensional material (just one atom thick) it
promises brilliant perspectives for the next generation of electronics which uses mainly
only surface of materials. I will tell about the first aspect of the graphene physics, some
unexpected relations between materials science and quantum field theory and high-energy
physics.
Electrons and holes in this material have properties similar to ultrarelativistic particles (twodimensional analog of massless Dirac fermions). This leads to some unusual and even
counterintuitive phenomena, such as finite conductivity in the limit of zero charge carrier
concentration (quantum transport by evanescent waves) or transmission of electrons
through high and broad poential barriers with a high probability (Klein tunneling). This
allows to study subtle effects of relativistic quantum mechanics and quantum field theory in
condensed-matter experiments, without accelerators and colliders. Some of these effects
were considered as practically unreachable. Apart from the Klein tunneling, this is, for
example, a vacuum reconstruction near supercritical charges predicted many years ago
for collisions of ultra-heavy ions. Another interesting class of quantum-relativistic
phenomena is related with corrugations of graphene, which are unavoidable for any twodimensional systems at finite temperature. As a result, one has not just massless Dirac
fermions but massless Dirac fermions in curved space. Gauge fields, of the central
concepts of modern physics, are quite real in graphene and one can manipulate them just
applying mechanical stress.
Institute of Science and Technology Austria | Am Campus 1 | 3400 Klosterneuburg
Symposium: “Condensed Matter Physics and Optics”
Time: 11.40
A single molecule approach towards biological pattern formation
Petra Schwille (Technical University Dresden, Biophysics Group)
Cell and developmental biology are immensely complex and rapidly growing fields that are
particularly in need of quantitative methods to determine their key processes. To
understand how cells polarize and develop into organisms, we need quantitative methods
to determine concentration gradients and diffusion coefficients of key factors such as
morphogens. Fluorescence Correlation Spectroscopy (FCS) is a powerful means for the
study of concentrations, translocation processes, molecular association or enzymatic
turnovers. It is fair to state that this technique raises strong hopes for quantitative systems
biology. During the past years, we applied FCS to a variety of cell-associated phenomena.
Recently, we established the possibility of determining how morphogen gradients form and
maintain in living embryos, thus opening up a manifold of attractive applications in
developmental biology.
In another, more fundamental approach, we are presently aiming to identify minimal
systems for biological self-organization that reveal fundamental mechanisms of how
structures and patterns can emerge from the interplay of molecules. As a particularly
exciting example for the power of minimal systems, self-organization of essential proteins
of the bacterial cell division machinery could be shown in a simple assay, consisting of
only two protein species, an energy source, and a membrane.
Institute of Science and Technology Austria | Am Campus 1 | 3400 Klosterneuburg
Symposium: “Condensed Matter Physics and Optics”
Time: 12.20
Bone: A Fascinating Material
Steve Weiner
Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel 76100
Bone has fascinated scientists since the first studies in the 1690’s. Bone the material to
this day still presents many enigmas. Bone is a composite material composed mainly of
minute crystals of the mineral carbonated hydroxyapatite, the fibrous protein collagen and
water. The crystals are plate-shaped, even though they crystallize in the hexagonal
system. They form mainly inside the collagen fibril, where they do not grow from a
saturated solution, but rather from a preformed highly disordered mineral phase called
amorphous calcium phosphate. The crystals continue to grow and push the collagen
molecules together. Older bone with more mineral fractures along crystal surfaces,
whereas younger bone with less mineral fractures around collagen fibrils. Even though the
building block of bone, the mineralized collagen fibril has a highly anisotropic structure,
these fibrils are arranged into a complex structure that is much less anisotropic. This
lamellar structure is thus better able to withstand mechanical challenges from all
directions, making bone a sort of all-purpose “concrete” of the vertebrate skeleton. Finally
certain bone cells are capable of removing older bone and others replace the space with
newer bone. Bone thus also has self-healing capabilities. Despite the hundreds of years of
investigation, much still remains to be understood about this fascinating material.
Institute of Science and Technology Austria | Am Campus 1 | 3400 Klosterneuburg
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