Tests of Lorentz Symmetry using X-ray Polarimetry

TL;DR

This paper presents new constraints on Lorentz symmetry violation derived from X-ray polarization measurements of active galactic nuclei, significantly improving previous optical-based limits.

Contribution

It provides the first constraints on Lorentz invariance violation using X-ray polarimetry, enhancing sensitivity by four orders of magnitude over prior optical measurements.

Findings

New constraints on Lorentz invariance violation from X-ray polarization data

Constraints improve previous optical-based limits by four orders of magnitude

Supports the robustness of Lorentz symmetry at astrophysical scales

Abstract

Lorentz symmetry is the fundamental symmetry of Einstein's theory of Special Relativity and has been tested to great precision. Nevertheless, the possibility remains that it is violated at the Planck scale, as predicted by some theories of quantum gravity. While the Planck scale is not directly accessible to experiments, minute residual deviations from Lorentz symmetry at attainable energies may be observable. The polarization of light from astrophysical sources is a particularly powerful probe because tiny differences accumulate as light travels over astrophysical distances, and polarization is sensitive to light travel time differences between polarization modes on the order of the oscillation period of the electromagnetic wave. Here, we report on new constraints on Lorentz invariance violation derived from X-ray polarization measurements of active galactic nuclei. The new constraints, presented in the framework of the Standard-Model Extension, improve on our previous work, which used optical polarization measurements, by four orders of magnitude.