The Atomic Superfluid Quantum Interference Device with tunable Josephson Junctions

TL;DR

This paper presents a theoretical analysis of an atomic superfluid quantum interference device (ASQUID) with tunable Josephson junctions, identifying key quantities for rotation sensing and exploring effects of junction tuning and initial phase differences.

Contribution

It introduces an analytical theory for ASQUID, highlighting the roles of critical population bias and critical time in rotation detection, and compares symmetric and asymmetric junction configurations.

Findings

Critical population bias varies periodically with rotation.

Symmetric junctions outperform asymmetric ones for rotation sensing.

Critical time can also be used to detect rotation.

Abstract

The atomic superfluid quantum interference device (ASQUID) with tunable Josephson junctions is theoretically investigated. ASQUID is a device that can be used for the detection of rotation. In this work we establish an analytical theory for the ASQUID using the tunneling Hamiltonian method and find two physical quantities that can be used for the rotation sensing. The first one is the critical population bias, which characterizes the transition between the self-trapping and the Josephson oscillation regimes and demonstrates a periodic modulation behavior due to the rotation of the system. We discuss the variation of critical population bias when the tunneling strengths of the junctions are tuned in different values, and find that the symmetric junctions are better choice than the asymmetric ones in terms of rotation sensing. Furthermore, how the initial phase difference between the two condensates affects the measurement of rotation is also discussed. Finally, we investigate the case of time-dependent junctions and find there is another physical quantity, named critical time, that can be used to detect the rotation.