Monitoring currents in cold-atom circuits

TL;DR

This paper investigates the dynamics of cold-atom circuits, particularly ring-shaped condensates coupled with guides, to develop minimally invasive methods for current detection and quantum rotation sensing.

Contribution

It introduces a novel approach to monitor condensate currents via a rectilinear guide, enabling minimally invasive diagnostics and potential quantum rotation sensors.

Findings

Distinctive dynamics for different winding numbers

Density depletion decay via Sagnac effect

Readout method minimally affects the ring condensate

Abstract

Complex circuits of cold atoms can be exploited to devise new protocols for the diagnostics of cold-atoms systems. Specifically, we study the quench dynamics of a condensate confined in a ring-shaped potential coupled with a rectilinear guide of finite size. We find that the dynamics of the atoms inside the guide is distinctive of the states with different winding numbers in the ring condensate. We also observe that the depletion of the density, localized around the tunneling region of the ring condensate, can decay in a pair of excitations experiencing a Sagnac effect. In our approach, the current states of the condensate in the ring can be read out by inspection of the rectilinear guide only, leaving the ring condensate minimally affected by the measurement. We believe that our results set the basis for definition of new quantum rotation sensors. At the same time, our scheme can be employed to explore fundamental questions involving dynamics of bosonic condensates.