New binary pulsar constraints on Einstein-{\ae}ther theory after GW170817

TL;DR

This paper refines constraints on Einstein-{ extperiodcentered}ether theory using pulsar timing data, especially after the GW170817 event, tightening bounds on Lorentz-violating parameters in gravity.

Contribution

It extends the calculation of pulsar sensitivities to the parameter space consistent with recent gravitational wave speed bounds, improving constraints on Einstein-{ extperiodcentered}ether theory.

Findings

Pulsar timing constrains are tightened by about an order of magnitude.

New sensitivity calculations cover the viable parameter space after GW170817.

Binary pulsar and triple system observations provide key constraints.

Abstract

The timing of millisecond pulsars has long been used as an exquisitely precise tool for testing the building blocks of general relativity, including the strong equivalence principle and Lorentz symmetry. Observations of binary systems involving at least one millisecond pulsar have been used to place bounds on the parameters of Einstein-{\ae}ther theory, a gravitational theory that violates Lorentz symmetry at low energies via a preferred and dynamical time threading of the spacetime manifold. However, these studies did not cover the region of parameter space that is still viable after the recent bounds on the speed of gravitational waves from GW170817/GRB170817A. The restricted coverage was due to limitations in the methods used to compute the pulsar sensitivities, which parameterize violations of the strong-equivalence principle in these systems. We extend here the calculation of pulsar sensitivities to the parameter space of Einstein-{\ae}ther theory that remains viable after GW170817/GRB170817A. We show that observations of the damping of the period of quasi-circular binary pulsars and of the triple system PSR J0337+1715 further constrain the viable parameter space by about an order of magnitude over previous constraints.