Precession of spheroids under Lorentz violation and observational consequences for neutron stars

TL;DR

This paper investigates how Lorentz violation affects the precession of spheroids, especially neutron stars, and explores observational consequences for pulsar signals and gravitational waves, providing new tests for fundamental physics.

Contribution

It introduces a novel solution for the rotation of free-precessing neutron stars under Lorentz violation and analyzes its observational implications.

Findings

Recovered Nordtvedt precession solution in SME framework

Derived new rotation solution for free-precessing stars with Lorentz violation

Proposed observational tests using pulsar signals and gravitational waves

Abstract

The Standard-Model Extension (SME) is an effective-field-theoretic framework that catalogs all Lorentz-violating field operators. The anisotropic correction from the minimal gravitational SME to Newtonian gravitational energy for spheroids is studied, and the rotation of rigid spheroids is solved with perturbation method and numerical approach. The well-known forced precession solution given by Nordtvedt in the parameterized post-Newtonian formalism is recovered and applied to two observed solitary millisecond pulsars to set bounds on the coefficients for Lorentz violation in the SME framework. A different solution, which describes the rotation of an otherwise free-precessing star in the presence of Lorentz violation, is found, and its consequences on pulsar signals and continuous gravitational waves (GWs) emitted by neutron stars (NSs) are investigated. The study provides new possible tests of Lorentz violation once free-precessing NSs are firmly identified in the future.