New limits on the local Lorentz invariance violation of gravity in the Standard-Model Extension with pulsars

TL;DR

This paper uses updated pulsar observations and a new analysis method to set stricter limits on local Lorentz invariance violation in gravity, improving previous bounds and exploring future potential for even tighter constraints.

Contribution

It introduces a novel parameter estimation approach and provides the most stringent pulsar-based limits on LV coefficients to date, with prospects for significant future improvements.

Findings

New limits on 8 linear combinations of LV coefficients

Precision improved by a factor of two to three over previous bounds

Potential for three to four orders of magnitude improvement with future pulsar observations

Abstract

Lorentz Violation (LV) is posited as a possible relic effect of quantum gravity at low energy scales. The Standard-Model Extension provides an effective field-theoretic framework for examining possible deviations attributed to LV. With their high observational accuracy, pulsars serve as ideal laboratories for probing LV. In the presence of LV, both the spin precession of solitary pulsars and orbital dynamics of binary pulsars would undergo modifications. Observations of pulse profiles and times of arrival (TOAs) of pulses allow for an in-depth investigation of these effects, leading to the establishment of strict limits on LV coefficients. We revisit the project of limiting local LV with updated pulsar observations. We employ a new parameter estimation method and utilize state-of-the-art pulsar timing observation data and get new limits on 8 linear combinations of LV coefficients based on 25 tests from 12 different systems. Compared to previous limits from pulsars, precision has improved by a factor of two to three. Additionally, we explore prospects for further improvements from pulsars. Simulation results indicate that more observations of spin precession in solitary millisecond pulsars could significantly enhance the accuracy of spatial LV coefficients, potentially by three to four orders of magnitude. As observational data accumulate, pulsars are anticipated to increasingly contribute to the tests of LV.