A Quantum Top Inside a Bose Josephson Junction

TL;DR

This paper models an atomic quantum dot within a Bose Josephson junction as a quantum top, revealing its sensitivity to condensate oscillations and its ability to influence tunneling dynamics.

Contribution

It introduces a novel pseudospin model of the quantum dot as a quantum top and analyzes its impact on condensate tunneling behavior.

Findings

Quantum dot acts as a pseudospin subject to external torque.

Strong coupling can modify or induce tunneling between condensates.

System is highly sensitive to deviations from linear oscillations.

Abstract

We consider an atomic quantum dot confined between two weakly-coupled Bose-Einstein condensates, where the dot serves as an additional tunneling channel. It is shown that the thus-embedded atomic quantum dot is a pseudospin subject to an external torque, and therefore equivalent to a quantum top. We demonstrate by numerical analysis of the time-dependent coupled evolution equations that this microscopic quantum top is very sensitive to any deviation from linear oscillatory behavior of the condensates. For sufficiently strong dot-condensate coupling, the atomic quantum dot can induce or modify the tunneling between the macroscopic condensates in the two wells.