Field-gradient measurement using a Stern-Gerlach atomic interferometer with butterfly geometry

Abstract

Atomic interferometers have been studied as a promising device for precise sensing of external fields. Among various configurations, a particular configuration with a butterfly-shaped geometry has been designed to sensitively probe field gradients. We introduce a Stern-Gerlach (SG) butterfly interferometer by incorporating magnetic field in the conventional butterfly-shaped configuration. Atomic trajectories of the interferometer can be flexibly adjusted by controlling magnetic fields to increase the sensitivity of the interferometer, while the conventional butterfly interferometer using Raman transitions can be understood as a special case. We also show that the SG interferometer can keep high contrast against a misalignment in position and momentum caused by the field gradient.

Stern-Gerlach Interferometry for Tests of Quantum Gravity and General Applications

“…Given the large volume of work that is dedicated exclusively to table-top quantum gravity, it is simply impossible to explore in depth, the motivations behind various proposals that have been put forward. Some that deserve a great deal of attention and careful thought nevertheless, include the conception of gedanken thought experiments [7] for tests of relativity (the authors in [7] for instance, demonstrate that any local experiment that distinguishes a coherent quantum superposition from a statistical mixture of quantum states involves a time scale that is proportional to the mass of the system under investigation), the realization of a novel Stern-Gerlach interferometer within which one considers the application of an unconventional magnetic field configuration [8] to probe magnetic field gradients at high sensitivities (the authors in [8] demonstrate that employing a butterfly-shaped configuration for the applied field in the interferometer ensures that a sufficiently strong interference signal strength be received towards the end of the interferometric scheme, even when the setup is subject to misalignments in position and momentum caused by the resulting field gradient), Mach-Zehnder matterwave interferometry using Bose-Einstein condensates [9] and the measurement of the fundamental constants of nature and other quantities of interest [10,11]. Moreover, in addition to gravity measurements, matter-wave interferometry is expected to find novel applications in a variety of other fields of interest, for instance quantum metrology, physics beyond the Standard Model, precision sensing and even core engineering disciplines, as we shall see in the subsequent sections.…”