New tests of local Lorentz invariance of gravity with smalleccentricity binary pulsars
Abstract
In the postNewtonian parametrization of semiconservative gravity theories, local Lorentz invariance (LLI) violation is characterized by two parameters, alpha_1 and alpha_2. In binary pulsars the isotropic violation of LLI in the gravitational sector leads to characteristic preferred frame effects (PFEs) in the orbital dynamics, if the barycenter of the binary is moving relative to the preferred frame with a velocity w. For smalleccentricity binaries, the effects induced by alpha_1 and alpha_2 decouple, and can therefore be tested independently. We use recent timing results of two compact pulsarwhite dwarf binaries with known 3D velocity, PSRs J1012+5307 and J1738+0333, to constrain PFEs for strongly selfgravitating bodies. We derive a limit alpha_2 < 1.8e4 (95% CL), which is the most constraining limit for strongly selfgravitating systems up to now. Concerning alpha_1, we propose a new, robust method to constrain this parameter. Our most conservative result, alpha_1 = 0.4^{+3.7}_{3.1} e5 (95% CL) from PSR J1738+0333, constitutes a significant improvement compared to current most stringent limits obtained both in Solar system and binary pulsar tests. We also derive corresponding limits for alpha_1 and alpha_2 for a preferred frame that is at rest with respect to our Galaxy, and preferred frames that locally comove with the rotation of our Galaxy. (Abridged)
 Publication:

Classical and Quantum Gravity
 Pub Date:
 October 2012
 DOI:
 10.1088/02649381/29/21/215018
 arXiv:
 arXiv:1209.4503
 Bibcode:
 2012CQGra..29u5018S
 Keywords:

 General Relativity and Quantum Cosmology;
 Astrophysics;
 Solar and Stellar Astrophysics;
 General Relativity and Quantum Cosmology;
 Astrophysics  Solar and Stellar Astrophysics
 EPrint:
 34 pages, 8 figures, 2 tables