Gravitational waves and the Sagnac effect

TL;DR

The paper explores how gravitational waves influence the Sagnac effect, proposing an antenna design to detect specific gravitational wave components, with implications for advanced gravitational wave detectors.

Contribution

It extends the general relativistic formula for the Sagnac effect to include gravitational wave effects and introduces a novel antenna design for detecting these effects.

Findings

Gravitational waves contribute to the Sagnac phase shift.

A new antenna design can isolate specific Weyl tensor components.

Implications for third-generation gravitational wave detectors.

Abstract

Light propagating in opposite directions around the same loop in general shows a relative phase shift when recombined. This phenomenon is known as the Sagnac effect after Georges Sagnac who, in 1913, demonstrated with an interferometer on a rotating table that the phase shift depended on the angular velocity of the table. In previous work we have given a very general formula for the Sagnac effect, valid in full general relativity. The relativistic effect not only contains the `classical' contribution from the rotation of the laboratory but also contributions due its acceleration and due to incoming gravitational waves. Here, we point out a major consequence of this gravitational effect which may have implications for third generation gravitational wave detectors. We describe an `antenna' design which picks out specific components of the Weyl tensor describing the incident gravitational waves.