Mesoscopic superfluid to superconductor transition

TL;DR

This paper explores the transition from superfluid to superconductor in a mesoscopic Bose-Hubbard circuit coupled to a cavity, analyzing spectral properties and emergent phenomena like the Meissner effect.

Contribution

It introduces a spectral tomography approach for a ring-shaped Bose-Hubbard circuit, revealing the interplay of interactions, cavity coupling, and emergent superconductivity.

Findings

Identifies superfluid, superconducting, and Mott insulator regions in the parameter space.

Discusses the mesoscopic Meissner effect and Anderson-Higgs mechanism.

Maps the phase diagram with interaction and coupling parameters.

Abstract

Spectrum tomography for the energy ($E$) of a ring-shaped Bose-Hubbard circuit is illustrated. There is an inter-particle interaction $U$ that controls superfluidity (SF) and the transition to the Mott Insulator (MI) regime. The circuit is coupled to an electromagnetic cavity mode of frequency $\omega_0$, and the coupling is characterized by a generalized fine-structure-constant $\alpha$ that controls the emergence of superconductivity (SC). The ${(U,\alpha,\omega_0,E)}$ diagram features SF and SC regions, a vast region of fragmented possibly chaotic states, and an MI regime for large $U$. The mesoscopic version of the Meissner effect and the Anderson-Higgs mechanism are discussed.