Sagnac effect in a chain of mesoscopic quantum rings

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 $\ensuremath{\Omega}$. 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 $\ensuremath{\Omega}$ with a slope $\ensuremath{\partial}T/\ensuremath{\partial}\ensuremath{\Omega}\ensuremath{\sim}{N}^{2}$. The steepness of this slope dramatically enhances the response to rotations in comparison to conventional single ring interferometers such as the Mach-Zehnder interferometer and leads to a phase sensitivity well below the quantum shot-noise limit typical of atom interferometers.