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Articles **1** - **14** of ** 14**

## Full-Text Articles in Physical Sciences and Mathematics

Recent Developments In Spacetime-Symmetry Tests In Gravity, Q. G. Bailey

#### Recent Developments In Spacetime-Symmetry Tests In Gravity, Q. G. Bailey

*Publications*

Motivated by potentially detectable but minuscule signatures from Planckscale or other new physics, there has been a substantial increase in tests of spacetime symmetry in gravity in recent years. Some novel hypothetical effects that break local Lorentz symmetry and CPT symmetry in gravitational experiments as well as solar system and astrophysical observations have been studied in recent works. Much of this work uses the effective field theory framework, the Standard-Model Extension (SME), that includes gravitational couplings. In other cases, the parameters in specific hypothetical models of Lorentz violation in gravity have been tested.

A 3+1 Decomposition Of The Minimal Standard-Model Extension Gravitational Sector, Nils A. Nilsson, Kellie O'Neal-Ault, Quentin G. Bailey

#### A 3+1 Decomposition Of The Minimal Standard-Model Extension Gravitational Sector, Nils A. Nilsson, Kellie O'Neal-Ault, Quentin G. Bailey

*Publications*

The 3+1 (ADM) formulation of General Relativity is used in, for example, canonical quantum gravity and numerical relativity. Here we present a 3+1 decomposition of the minimal Standard-Model Extension gravity Lagrangian. By choosing the leaves of foliation to lie along a timelike vector field we write the theory in a form which will allow for comparison and matching to other gravity models.

Testing The Gravitational Weak Equivalence Principle In The Standard-Model Extension With Binary Pulsars, Lijing Shao, Quentin G. Bailey

#### Testing The Gravitational Weak Equivalence Principle In The Standard-Model Extension With Binary Pulsars, Lijing Shao, Quentin G. Bailey

*Publications*

The standard model extension provides a framework to systematically investigate possible violation of the Lorentz symmetry. Concerning gravity, the linearized version was extensively examined. We here cast the first set of experimental bounds on the nonlinear terms in the field equation from the anisotropic cubic curvature couplings. These terms introduce body-dependent accelerations for self-gravitating objects, thus violating the gravitational weak equivalence principle (GWEP). Novel phenomena, which are absent in the linearized gravity, remain experimentally unexplored. We constrain them with precise binary-orbit measurements from pulsar timing, wherein the high density and large compactness of neutron stars are crucial for the test ...

First Search For Nontensorial Gravitational Waves From Known Pulsars, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, B. Hughey, J. W. W. Pratt, E. Schmidt, S. G. Schwalbe, M. J. Szczepańczyk, M. Zanolin, Et Al.

#### First Search For Nontensorial Gravitational Waves From Known Pulsars, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, B. Hughey, J. W. W. Pratt, E. Schmidt, S. G. Schwalbe, M. J. Szczepańczyk, M. Zanolin, Et Al.

*Publications*

We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector, or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper ...

Constraints On Sme Coefficients From Lunar Laser Ranging, Very Long Baseline Interferometry, And Asteroid Orbital Dynamics, C. Le Poncin-Lafitte, A. Bourgoin, A. Hees, S. Bouquillon, S. Lambert, Q. G. Bailey, Et Al.

#### Constraints On Sme Coefficients From Lunar Laser Ranging, Very Long Baseline Interferometry, And Asteroid Orbital Dynamics, C. Le Poncin-Lafitte, A. Bourgoin, A. Hees, S. Bouquillon, S. Lambert, Q. G. Bailey, Et Al.

*Publications*

Lorentz symmetry violations can be parametrized by an effective field theory framework that contains both General Relativity and the Standard Model of particle physics, called the Standard-Model Extension or SME. We consider in this work only the pure gravitational sector of the minimal SME. We present new constraints on the SME coefficients obtained from lunar laser ranging, very long baseline interferometry, and planetary motions.

Prospects For Sme Tests With Experiments At Syrte And Lkb, C. Guerlin, H. Pihan-Le Bars, Q. G. Bailey, P. Wolf

#### Prospects For Sme Tests With Experiments At Syrte And Lkb, C. Guerlin, H. Pihan-Le Bars, Q. G. Bailey, P. Wolf

*Publications*

Preliminary work has been done in order to assess the perspectives of metrology and fundamental physics atomic experiments at SYRTE and LKB in the search for physics beyond the Standard Model and General Relativity. The first studies we identified are currently ongoing with the Microscope mission and with a Cs fountain clock. The latter brings significant improvement on the proton-sector coefficient cTT down to the 10−17 GeV level.

Testing Lorentz Symmetry With Planetary Orbital Dynamics, A. Hees, Q. G. Bailey, C. Le Poncin-Lafitte, A. Bourgoin, A. Rivoldini, B. Lamine, F. Meynadier, C. Guerlin, P. Wolf

#### Testing Lorentz Symmetry With Planetary Orbital Dynamics, A. Hees, Q. G. Bailey, C. Le Poncin-Lafitte, A. Bourgoin, A. Rivoldini, B. Lamine, F. Meynadier, C. Guerlin, P. Wolf

*Publications*

Planetary ephemerides are a very powerful tool to constrain deviations from the theory of general relativity (GR) using orbital dynamics. The effective field theory framework called the Standard-Model Extension (SME) has been developed in order to systematically parametrize hypothetical violations of Lorentz symmetry (in the Standard Model and in the gravitational sector). In this communication, we use the latest determinations of the supplementary advances of the perihelia and of the nodes obtained by planetary ephemerides analysis to constrain SME coefficients from the pure gravity sector and also from gravity-matter couplings. Our results do not show any deviation from GR and ...

Short-Range Gravity And Lorentz Violation, Quentin G. Bailey, V. Alan Kostelecký, Rui Xu

#### Short-Range Gravity And Lorentz Violation, Quentin G. Bailey, V. Alan Kostelecký, Rui Xu

*Publications*

Comparatively few searches have been performed for violations of local Lorentz invariance in the pure-gravity sector. We show that tests of short-range gravity are sensitive to a broad class of unconstrained and novel signals that depend on the experimental geometry and on sidereal time.

Field Localization And The Nambu-Jona-Lasinio Mass Generation Mechanism In An Alternative 5-Dimensional Brane Model, Preston Jones, Gerardo Muñoz, Douglas Singleton, Triyanta

#### Field Localization And The Nambu-Jona-Lasinio Mass Generation Mechanism In An Alternative 5-Dimensional Brane Model, Preston Jones, Gerardo Muñoz, Douglas Singleton, Triyanta

*Publications*

We consider a five-dimensional brane world model with a single brane which is distinct from the well known Randall-Sundrum model. We discuss the similarities and differences between our brane model and the Randall-Sundrum brane model. In particular we focus on the localization of five-dimensional fields with different spins—spin 0, spin 1 / 2 , and spin 1—to the brane, and a self-consistent mass-generation mechanism. We find that the brane model studied here has different (and in some cases superior) localization properties for fields/particles with different spins to the brane, as compared to the original five-dimensional brane models. In addition ...

Application Of Asymptotic Expansions For Maximum Likelihood Estimators' Errors To Gravitational Waves From Inspiraling Binary Systems: The Network Case, Salvatore Vitale, Michele Zanolin

#### Application Of Asymptotic Expansions For Maximum Likelihood Estimators' Errors To Gravitational Waves From Inspiraling Binary Systems: The Network Case, Salvatore Vitale, Michele Zanolin

*Publications*

This paper describes the most accurate analytical frequentist assessment to date of the uncertainties in the estimation of physical parameters from gravitational waves generated by nonspinning binary systems and Earth-based networks of laser interferometers. The paper quantifies how the accuracy in estimating the intrinsic parameters mostly depends on the network signal to noise ratio (SNR), but the resolution in the direction of arrival also strongly depends on the network geometry. We compare results for 6 different existing and possible global networks and two different choices of the parameter space. We show how the fraction of the sky where the one ...

New Tests Of General Relativity, Quentin Bailey

#### New Tests Of General Relativity, Quentin Bailey

*Publications*

The last decade has seen a rapid increase in the number of precision tests of relativity. This research has been motivated by the intriguing possibility that tiny deviations from relativity might arise in the underlying theory that is widely believed to successfully mesh General Relativity (GR) with quantum physics. Many of these tests have been analyzed within an effective field theory framework which generically describes possible deviations from exact relativity and contains some traditional test frameworks as limiting cases. One part of the activity has been a resurgence of interest in tests of relativity in the Minkowski-spacetime context, where Lorentz ...

Lorentz Violation And Gravity, Quentin G. Bailey

#### Lorentz Violation And Gravity, Quentin G. Bailey

*Publications*

In the last decade, a variety of high-precision experiments have searched for miniscule violations of Lorentz symmetry. These searches are largely motivated by the possibility of uncovering experimental signatures from a fundamental unified theory. Experimental results are reported in the framework called the Standard-Model Extension (SME), which describes general Lorentz violation for each particle species in terms of its coefficients for Lorentz violation. Recently, the role of gravitational experiments in probing the SME has been explored in the literature. In this talk, I will summarize theoretical and experimental aspects of these works. I will also discuss recent lunar laser ranging ...

The Equivalence Principle, Uniformly Accelerated Reference Frames, And The Uniform Gravitational Field, Gerardo Muñoz, Preston Jones

#### The Equivalence Principle, Uniformly Accelerated Reference Frames, And The Uniform Gravitational Field, Gerardo Muñoz, Preston Jones

*Publications*

The relation between uniformly accelerated reference frames in flat spacetime and the uniform gravitational field is examined in a relativistic context. It is shown that contrary to previous statements, equivalence does not break down in this context. No restrictions to Newtonian approximations or small enclosures are necessary.

Main Sequence Masses And Radii From Gravitational Redshifts, Ted Von Hippel

#### Main Sequence Masses And Radii From Gravitational Redshifts, Ted Von Hippel

*Publications*

Modern instrumentation makes it possible to measure the mass to radius ratio for main sequence stars in open clusters from gravitational redshifts. For stars where independent information is available for either the mass or the radius, this application of general relativity directly determines the other quantity. Applicable examples are: 1) measuring the radii of solar metallicity main sequence stars for which the mass - luminosity relation is well known, 2) measuring the radii for stars where model atmospheres can be used to determine the surface gravity (the mass to radius squared ratio), 3) refining the mass - radius relation for main sequence ...