SEARCHES FOR TRANSIENT AND
OSCILLATING EXOTIC SPINDEPENDENT INTERACTIONS
Derek F. Jackson Kimball
Collaborators (Experiment)
Dmitry Budker
Szymek Pustelny
Alex Sushkov
Wojtek Gawlik
Micah Ledbetter
…and many
students!
Collaborators (Theory and Analysis)
Maxim Pospelov
Surjeet Rajendran
Peter Graham
Chris Pankow
Josh Smith
Outline



Brief review of “traditional” searches for new spin-dependent
interactions;
A new search for transient spin-dependent interactions of
astrophysical origin:
GNOME: the Global Network of Optical
Magnetometers to search for Exotic physics;
A new search for oscillating spin-dependent interactions (and
the QCD axion):
CASPEr: the Cosmic Axion Spin Precession Experiment.
Why study fundamental physics?
Max Zolotorev
Physicists are
3% of rat.
Exotic spin-dependent interactions
New scalar/pseudoscalar bosons (axion)
and vector/axial-vector bosons generate new forces:
J. E. Moody and F. Wilczek, Phys. Rev. D 30, 130 (1984);
B. A. Dobrescu and I. Mocioiu, J. High Energy Phys. 11, 5 (2006).
New scalar/pseudoscalar bosons (axion)
and vector/axial-vector bosons generate new forces:
J. E. Moody and F. Wilczek, Phys. Rev. D 30, 130 (1984);
B. A. Dobrescu and I. Mocioiu, J. High Energy Phys. 11, 5 (2006).
Spin-dependent interactions
Exotic spin-dependent interactions
exert torques on atomic
constituents (electrons and nuclei),
leading to spin precession.
Long-range monopole-dipole
(spin-gravity?) interaction
Hamiltonian in Earth’s field:
Shift of Zeeman sublevels
Spin precession

g

S
0
E
M = -1
M=0
M=1
Dual-isotope Rb comagnetometer
W
W
Wg
WL85
87Rb
85Rb
Wg
WL87
Dual-isotope Rb comagnetometer
Form ratio of difference/sum of
precession frequencies:
Dual-isotope Rb comagnetometer
Form ratio of difference/sum of
precession frequencies:
= 0 if there is no spin-gravity interaction,
 0 if there is a spin-gravity interaction.
Preliminary data: time domain
Preliminary data: frequency domain
Lorentzian function:
Progress report published in:
Annalen der Physik 525(7), 514-528 (2013).
10
Proton constraints
-26
p s
Coupling strength (|g g |/c)
10 -28
10 -30
10 -32
10 -34
10 -36
laboratory
limits
Youdin et al. (1996)
Raffelt (2012)
Projected constraints from our experiment
10 -38
10 -2
10 0
10 2
10 4
10 6
10 8
Length scale  (m)
D. F. Jackson Kimball, arXiv:1407.2671 (2015).
astrophysical
limits
10 10
10 12
Short-range dipole-dipole interactions
Short-range dipole-dipole interactions
M. P. Ledbetter et al., Phys. Rev. Lett. 110, 040402 (2013).
Short-range dipole-dipole interactions
S. Kotler et al., arXiv:1501.07891 (2015).
Short-range dipole-dipole interactions
S. Kotler et al., arXiv:1501.07891 (2015).
Transient spin-dependent effects
Global Network
of Optical
Magnetometers
to search for
Exotic Physics
(GNOME)
GNOME
Transient event at a single
sensor could not be
distinguished from noise.
However, a global array of
sensors could confidently
detect transient events!
M. Pospelov, S. Pustelny, M. P. Ledbetter, D. F. Jackson Kimball,
W. Gawlik, and D. Budker, Phys. Rev. Lett. 110, 021803 (2013).
Pseudoscalar domain walls
Shortly after the Big Bang,
regions of space with different
energy-degenerate
pseudoscalar vacua form,
separated by domain walls.
Depending on properties
could contribute to dark
matter or dark energy.
At the domain walls: sharp
gradient gives atomic spins a
“kick” that could be detected.
Pseudoscalar domain walls
Characteristic wall thickness:
Characteristic mass/area:
Cosmologically plausible wall
separation:
Hamiltonian for spin interaction
with domain wall:
Pseudoscalar domain walls
Energy density:
Proof of principle experiment published in:
Annalen der Physik 525(8-9), 659-670 (2013).
GNOME: proof of principle
Correlated data from existing
shielded magnetometers
were acquired at 2 sites.
GNOME prototype detector
Rb-K-He-3 SERF
comagnetometer sensor
(similar to that designed by
Romalis, Kornack, and
collaborators at Princeton).
M. Smiciklas et al., Phys. Rev. Lett. 107, 171604 (2011).
GNOME prototype detector
M. Smiciklas et al., Phys. Rev. Lett. 107, 171604 (2011).
Projected sensitivity:
GNOME: other search possibilities?
• Correlated noise (spacetime foam)?
• Burst of anomalous field from
cataclysmic astrophysical
event (torsion gravity wave)?
• Lorentz violation coupled to gravity?
• Cosmic strings?
• Other (crazy) ideas?
Oscillating spin-dependent effects
Oscillating axion field as dark matter
P. W. Graham and S. Rajendran, Phys. Rev. D 88, 1035023 (2013).
Cosmic Axion Spin Precession Experiment
(CASPEr)
Cosmic Axion Spin Pr ecession Exper iment
D. Budker et al., Phys. Rev. X 4, 021030 (2014).
Nuclear Magnetic Resonance (NMR)
NMR resonant spin flip when Larmor frequency
Oscillating axion field
Axion affects physics of nucleus, NMR is sensitive probe.
Oscillating nuclear EDM, couples to electric field
and acts as “pseudo magnetic field.”
Oscillating axion field
Axion affects physics of nucleus, NMR is sensitive probe.
Gradient of axion field couples to nuclei
acts as “pseudo magnetic field.”
Nuclear Magnetic Resonance (NMR)
Axion affects physics of nucleus, NMR is sensitive probe.
SQUID
pickup
loop
axion “wind”
or
Larmor frequency = axion mass ➔ resonant enhancement
CASPEr Wind
CASPEr Wind
CASPEr Electric
1st generation:
Use a ferroelectric such as
PbTiO3 and thermal polarization
at high field.
Scan magnetic field and search
for axion NMR resonance.
2nd generation:
Use hyperpolarized, larger
volume sample (new species?).
Extend spin coherence time to
take advantage of full axion
coherence time.
Physicists are 3% of rat.
Traditional laboratory searches for exotic spindependent interactions have made significant
progress.
New laboratory searches for transient and oscillating
spin-dependent effects of astrophysical origin (dark
matter, dark energy, ???) offer exciting possibilities to
discover exotic physics!
Conclusions
Thank you!