New Limit on Lorentz Violation Using a Double-Pass Optical Ring Cavity

TL;DR

This paper reports a highly sensitive optical experiment that sets new stringent limits on Lorentz violation in electrodynamics, improving previous bounds by significant factors.

Contribution

The study introduces a double-pass optical ring cavity with a dielectric element to enhance sensitivity to Lorentz violation, achieving more precise constraints within the Standard Model Extension framework.

Findings

No evidence for Lorentz violation at δc/c ≲ 10^{-14}

Set new upper limits on odd-parity parameters in the SME

Improved bounds on scalar parameter by a factor of 12

Abstract

A search for Lorentz violation in electrodynamics was performed by measuring the resonant frequency difference between two counterpropagating directions of an optical ring cavity. Our cavity contains a dielectric element, which makes our cavity sensitive to the violation. The laser frequency is stabilized to the counterclockwise resonance of the cavity, and the transmitted light is reflected back into the cavity for resonant frequency comparison with the clockwise resonance. This double-pass configuration enables a null experiment and gives high common mode rejection of environmental disturbances. We found no evidence for odd-parity anisotropy at the level of $\delta c /c \lesssim 10^{-14}$. Within the framework of the Standard Model Extension, our result put more than 5 times better limits on three odd-parity parameters $\tilde{\kappa}^{JK}_{o+}$ and a 12 times better limit on the scalar parameter $\tilde{\kappa}_{\tr}$ compared with the previous best limits.