Nonclassical states in strongly correlated bosonic ring ladders

TL;DR

This paper investigates the ground state properties of a bosonic ring ladder with gauge flux, revealing a transition from fragmented single-particle states to fragmented Fermi seas as interactions increase, using exact diagonalization and fermionization.

Contribution

It introduces a combined approach of exact diagonalization and fermionization to analyze nonclassical states in bosonic ring ladders with gauge flux, highlighting a transition in fragmentation behavior.

Findings

Ground state transitions from two single-particle states to two Fermi seas with increasing interactions.

Fragmentation characterized by eigenvalues of the reduced density matrix and state fidelity.

Nonclassical states analyzed via momentum distribution, chiral currents, and current correlations.

Abstract

We study the ground state of a bosonic ring ladder under a gauge flux in the vortex phase, corresponding to the case where the single-particle dispersion relation has two degenerate minima. By combining exact diagonalization and an approximate fermionization approach we show that the ground state of the system evolves from a fragmented state of two single-particle states at weak interparticle interactions to a fragmented state of two Fermi seas at large interactions. Fragmentation is inferred from the study of the eigenvalues of the reduced single-particle density matrix as well as from the calculation of the fidelity of the states. We characterize these nonclassical states by the momentum distribution, the chiral currents and the current-current correlations.