Sagnac effect in a chain of mesoscopic quantum rings

TL;DR

This paper investigates how a chain of quantum rings can be used to detect rotations with high sensitivity, showing that the setup enhances the Sagnac effect and surpasses traditional interferometers in phase sensitivity.

Contribution

It introduces a model of ballistic matter wave transport in a chain of coupled quantum rings, demonstrating enhanced rotation sensitivity due to zero transmission gaps and sharp transition behavior.

Findings

Transmission exhibits zero gaps as a function of rotation rate.

Sensitivity scales with the square of the number of rings, N^2.

Response to rotation surpasses the standard quantum limit.

Abstract

The ability to interferometrically detect inertial rotations via the Sagnac effect has been a strong stimulus for the development of atom interferometry because of the potential 10^{10} enhancement of the rotational phase shift in comparison to optical Sagnac gyroscopes. Here we analyze ballistic transport of matter waves in a one dimensional chain of N coherently coupled quantum rings in the presence of a rotation of angular frequency, \Omega. We show that the transmission probability, T, exhibits zero transmission stop gaps as a function of the rotation rate interspersed with regions of rapidly oscillating finite transmission. With increasing N, the transition from zero transmission to the oscillatory regime becomes an increasingly sharp function of \Omega with a slope \partialT/\partial \Omega N^2. The steepness of this slope dramatically enhances the response to rotations in comparison to conventional single ring interferometers such as the Mach-Zehnder and leads to a phase sensitivity well below the standard quantum limit.