The emergence of atomic semifluxons in optical Josephson junctions

TL;DR

This paper introduces a method to generate and control pairs of semifluxons in optical Josephson junctions using atomic Bose-Einstein condensates, enabling dynamic state manipulation and potential observation of quantum oscillations.

Contribution

It presents a novel optical system for creating and tuning semifluxon pairs in atomic BECs, with a mean-field model explaining degeneracy and static configurations.

Findings

Degenerate semifluxon-pair states identified

Dynamic tuning induces semifluxon formation

Potential to observe macroscopic quantum oscillations

Abstract

We propose to create pairs of semifluxons starting from a flat-phase state in long, optical 0-pi-0 Josephson junctions formed with internal electronic states of atomic Bose-Einstein condensates. In this optical system, we can dynamically tune the length of the pi-junction, the detuning of the optical transition, or the strength of the laser-coupling, to induce transitions from the flat-phase state to such a semifluxon-pair state. Similarly as in superconducting 0-pi-0 junctions, there are two, energetically degenerate semifluxon-pair states. A linear mean-field model with two internal electronic states explains this degeneracy and shows the distinct static field configuration in a phase-diagram of the junction parameters. This optical system offers the possibility to dynamically create a coherent superposition of the distinct semifluxon-pair states and observe macroscopic quantum oscillation.