Quentin's Research Interests
Attention Space Physics students with an interest in
theory!
I have several research projects related to my research
area which I have designed with the Space Physics curriculum in mind.
Anyone interested is encouraged to come and talk to me
(email:baileyq@erau.edu).
I am interested in foundational tests of our best current fundamental theories of physics,
the theory of gravity, General Relativity,
and the Standard Model of particle physics.
So far,
I have been studying the theoretical and experimental
aspects of testing the Einstein Equivalence Principle,
a foundation of General Relativity.
In particular I have focused on tests of Lorentz symmetry,
the spacetime symmetry of Special Relativity,
and also the discrete spacetime symmetry called CPT.
The motivation for this work is twofold.
First, spacetime symmetries are cornerstone of modern physics.
As such, it should be an experimental precedent to test these principle
in as many ways as possible.
Second, recent work on fundamental theories of physics,
that attempt to unify the Standard Model of
particle physics and General Relativity,
has pointed to the possibility of deviations from perfect spacetime symmetry.
In the ongoing search for new physics in turns out that highprecision,
typically lowenergy tests of Lorentz and CPT symmetry offer a
promising alternative to conventional highenergy accelerator experiments.
This area of research has grown considerably in the past decades and there is now
a dedicated research center at Indiana University called the Indiana
University Center for Spacetime Symmetries (IUCSS).
My own work,
in the publications below,
has been on the electromagnetic, nuclear, and gravitational
sectors of a general effective field theory framework
for testing Lorentz and CPT symmetry
called the StandardModel Extension (SME).
Information about the SME theoretical and experimental program,
including links to refereed journal articles, books,
and popular magazine articles,
can be found at this link:
Information about CPT and Lorentz Violation.
Publications:

"Testing the Gravitational Weak Equivalence Principle in the StandardModel Extension with Binary Pulsars"
accepted in Physical Review D
link

"Testing velocitydependent CPTviolating gravitational forces with radio pulsars"
accepted in Physical Review D
link

Relating Noncommutative SO(2,3)* Gravity to the
LorentzViolating StandardModel Extension,
Symmetry 2018, 10, 480
link

Velocitydependent inverse cubic force and solarsystem gravity tests,
Phys. Rev. D 96, 064035 (2017)
link

Lorentzsymmetry test at Planckscale suppression with nucleons in a spinpolarized Cesium cold atom clock,
(with Helene PihanLe Bars et al), Phys. Rev. D 95, 075026 (2017)
link

Tests of Lorentz symmetry in the gravitational sector,
with Aurelien Hees et al, review article, Universe 2, 4 (2016)
link

Anisotropic cubic curvature couplings,
Phys. Rev. D 94, 065029 (2016)
link
 Constraints on SME coefficients from Lunar Laser Ranging, Very Long Baseline Interferometry, and Asteroid Dynamics,
(with C. Le PoncinLafitte et al) presented at the Seventh Meeting on CPT and Lorentz Symmetry, June 2016,
link
 Gravity Sector of the SME,
presented at the Seventh Meeting on CPT and Lorentz Symmetry, June 2016,
link

Combined search for Lorentz violation in shortrange gravity
(with C.G. Shao et al), Phys. Rev. Lett. 117, 071102 (2016)
link

Testing Lorentz symmetry with planetary dynamics
(with A. Hees et al.) Phys. Rev. D 92, 064049 (2015)
link

What do we know about Lorentz symmetry?
presented at the 50th Rencontres de Moriond, "Gravitation: 100 years
after GR"
link

Shortrange gravity and Lorentz violation,
(with V.A. Kostelecky and Rui Xu),
Phys. Rev. D 91 , 022006 (2015)
link
 Quantum Tests of the Einstein Equivalence Principle with the
STEQUEST Space Mission,
Advances in Space Research 55, 501 (2015)
link
 Limits on violations of Lorentz Symmetry from Gravity Probe B,
Phys. Rev. D 88, 102001 (2013) (with J. Overduin and R. Everett)
link
 Local LorentzSymmetry Breaking and Gravity,
presented at the Sixth Meeting on CPT and Lorentz Symmetry, June 2013,
link
 Constraints on violations of Lorentz Symmetry from Gravity Probe B,
(with J. Overduin and R. Everett), presented at the Sixth Meeting on CPT and Lorentz Symmetry, June 2013,
link
 Lightbending tests of Lorentz invariance, (with
undergraduate Rhondale Tso), Phys. Rev. D 84, 085025 (2011)
link
 New tests of General Relativity, in Matters of Gravity, The
Newsletter of the Topical Group on Gravitation of the American Physical
Society, Volume 36, Fall 2010
link
 Gravity Couplings in the StandardModel Extension,
in CPT and Lorentz Symmetry V, World Scientific, 2011.
link
 Gravitational Lensing and Light Bending as tests of Lorentz
Symmetry,(with Rhondale Tso),
in CPT and Lorentz Symmetry V, World Scientific, 2011.
 Lorentzviolating gravitoelectromagnetism, Phys. Rev. D
82, 065012 (2010).
link
 Lorentz violation with an antisymmetric tensor,
(with
B. Altschul and
V.A. Kostelecky), Phys. Rev. D 81, 065028 (2010).
link
 Lorentz Violation and Gravity,
in Proceedings of the International Astronomical Union (IAU)
Symposium 261: Relativity in Fundamental Astronomy, 2009.
link
 Catching relativity violations with atoms,
Physics 2, 58, 2009.
link
 Timedelay and Doppler tests of the Lorentz symmetry
of gravity,Phys. Rev. D 80, 044004 (2009).
link
 Testing Lorentz Symmetry with Gravity,
in CPT and Lorentz Symmetry IV, World Scientific, 2008.
link
 Lorentz Violation and Gravity,
Ph.D. dissertation, Indiana University, 2007.
 Signals for Lorentz Violation in PostNewtonian Gravity
(with V.A. Kostelecky),
Phys. Rev. D 74, 045001 (2006). [TOPCITE 250+]
link
 LorentzViolating Electromagnetostatics,
in CPT and Lorentz Symmetry III, World Scientific, 2005.
link
 LorentzViolating Electrostatics and Magnetostatics
(with V.A. Kostelecky), Phys. Rev. D 70, 076006 (2004). [TOPCITE 150+]
link
In the SME formalism,
Lorentz violation for a given particle type (species)
is described by its coefficients for
Lorentz violation.
In certain special cases,
we can visualize these coefficients as a
background field of arrows,
pointing in some direction,
that affects our measuring apparatus (rods and clocks) as they move
or rotate through the background.
This is illustrated in the animation above for blue and green
rods and clocks.
As the two sets of rods and clocks rotate their
relative lengths and ticking rates will change if Lorentz symmetry
is violated.
If deviations from perfect Lorentz symmetry occur in nature,
they must be miniscule.
This implies that the best method for finding Lorentz violation is
to use the most sensitive "rods" and "clocks" available with today's
technology.
In practice,
a variety of real physical systems
can be used as effective rods and clocks.
For example,
some of the systems that have been used to test Lorentz symmetry
include hydrogen atoms, cesium atoms, torsion pendula,
superconducting gravimeters, electromagnetic resonant cavities,
the EarthMoon system, and even distant light propagating
from the early universe.
For weak gravitational fields,
there are nine independent coefficients for Lorentz violation
in the
puregravity sector of the (minimal) SME.
These coefficients would vanish in the limit that (local) Lorentz
symmetry holds for gravity.
Searches for nonzero gravity coefficients
include a variety of laboratory experiments,
solarsystem observations,
and beyond.
For example,
analysis of lunar laser ranging data
can place stringent constraints on these coefficients.
In the figure below, Lorentz violation (arrows)
could cause the Moon to deviate from its usual elliptical path.
Kostelecky and Tasson have analyzed mattergravity
couplings in the SME framework. Their work reveals new types of
unexplored signals for Lorentz violation in gravitational tests:
Mattergravity couplings and Lorentz violation,
Alan Kostelecky and Jay Tasson
link
Prospects for Large Relativity Violations in
MatterGravity Couplings,
Alan Kostelecky and Jay Tasson
link
More recently, Bailey, Kostelecky, Mewes, Tasson and Xu have studied the gravity sector nonminimal SME in a series of publications. This introduces a large number of coefficients
classified by the mass dimension of the operators appearing in the lagrangian. These coefficients can be measured in precision shortrange gravity tests as well as
gravitational wave measurements. The publications on the nonminimal gravitational SME include:
Shortrange gravity and Lorentz violation,
(with V.A. Kostelecky and Rui Xu),
Phys. Rev. D 91 , 022006 (2015)
link
Constraints on Lorentz Violation from Gravitational Cherenkov Radiation,
Phys. Lett. B 749, 551 (2015)
link
Testing local Lorentz invariance with gravitational waves,
Phys. Lett. B 757, 510 (2016)
link
There are nineteen independent coefficients for Lorentz violation
in the "minimal" version of the
photon sector of the SME.
Astrophysical observations and laboratory resonantcavity tests have
probed for these photon coefficients.
Lorentz violation could also affect other known particles,
such as
neutrinos,
and many experiments have already been performed.
So far,
no statistically convincing evidence exists that any coefficients
for Lorentz violation are nonzero.
However,
future experiments may dramatically
improve existing sensitivities,
and may yet discover miniscule Lorentz violation.
Gravity sector experimental/observational analyses using the SME framework

Gravitational Waves and GammaRays from a Binary Neutron Star Merger: GW170817 and GRB 170817A,
B. Abbott et al. (LSC collaboration), Astrophys. J. 848, L2 (2017)
link

Limits on Lorentz violation in gravity form worldwide superconducting gravimeters,
submitted for publication
link

Lorentz symmetry violations from mattergravity couplings with Lunar Laser Ranging,
A. Bourgoin et al., submitted for publication
link

Superconducting Gravimeter Tests of Local Lorentz Invariance,
N. Flowers et al., accepted in Phys. Rev. Lett.
link

Testing Lorentz symmetry with Lunar Laser Ranging,
A. Bourgoin et al., Phys. Rev. Lett. 117, 241301 (2016)
link

Lorentz symmetry and Very Long Baseline Interferometry,
C. Le PoncinLafitte, A. Hees, and S. Lambert, Phys. Rev. D 94, 125030 (2016)
link

Tests of gravitation with Gaia observations of Solar System Objects,
A. Hees, D. Hestroffer, C. Le PoncinLafitte, and P. David
link

Search for Lorentz invariance through tests of the gravitational
inverse square law at shortranges,
C.G. Shao et al., Phys. Rev. D 91, 102007 (2015)
link

Search for Lorentz violation in shortrange gravity,
J.C. Long and V.A. Kostelecky, Phys. Rev. D 91, 092003 (2015)
link

New pulsar limit on local Lorentz invariance violation of gravity
in the standardmodel extension,Lijing Shao, Phys.
Rev. D 90, 122009 (2014)
link

Tests of local Lorentz invariance violation of gravity in the standard model extension
with pulsars,Lijing Shao, Phys. Rev. Lett. 112, 111103 (2014)
link

Equivalence Principle and Bound Kinetic Energy,
Michael Hohensee, Holger Mueller, and R.B. Wiringa
link
 Simulations of Solar System observations in alternative theories of gravity,
Aurelien Hees et al., proceedings of the 13th Marcel Grossmann Meeting
link
 Orbital effects of Lorentzviolating Standard Model Extension gravitomagnetism around
a static body: a sensitivity analysis,
Lorenzo Iorio, Class. Quant. Grav. 29, 175007 (2012)
link
 Equivalence Principle and Gravitational Redshift,
Michael Hohensee, Steven Chu, Achim Peters, Holger Mueller,
Phys. Rev. Lett. 106, 151102 (2011).
link
 Gravitational Redshift, Equivalence Principle, and Matter
Waves,
Michael Hohensee et al. link

Search for Lorentz Violation in a HighFrequency Gravitational
Experiment below 50 microns,
D. Bennet, V. Skavysh, and J. Long,
presented at the Fifth Meeting on CPT and Lorentz Symmetry
link

Atom interferometry tests of local Lorentz invariance
in gravity and electrodynamics,
KengYeow Chung, Shengwey Chiow, Sven Herrmann, Steven Chu,
Holger Mueller, Phys. Rev. D 80, 016002 (2009).
link

Atom interferometry tests of the isotropy of postNewtonian
gravity,
Holger Mueller, Shengwey Chiow, Sven Herrmann, Steven Chu,
KengYeow Chung, Phys. Rev. Lett. 100, 031101 (2008).
link

Search for Lorentz Violation in a HighFrequency Gravitational
Experiment below 50 microns,
Joshua Long,
in V.A. Kostelecky (editor), CPT and Lorentz Symmetry IV, World
Scientific, 2008.

Testing for Lorentz Violation:
Constraints on StandardModel Extension Parameters
via Lunar Laser Ranging,
James B.R. Battat
, John F. Chandler,
Christopher W. Stubbs, Phys. Rev. Lett. 99, 241103 (2007).
link

From Gravity Probe B to STEP: Testing Einstein in Space,
James Overduin,
in V.A. Kostelecky (editor), CPT and Lorentz Symmetry IV, World
Scientific, 2008.

Atom Interferometry Experiments in Fundamental Physics,
Holger Mueller,
in V.A. Kostelecky (editor), CPT and Lorentz Symmetry IV, World
Scientific, 2008.
A summary of the current experimental constraints on
the many coefficients for Lorentz violation in the SME can be found
here.
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