Novel phases in rotating Bose-condensed gas: vortices and quantum correlation

TL;DR

This paper investigates the quantum phases and vortex structures in a rotating Bose-condensed gas using exact diagonalization, revealing stable states, vortex formations, and quantum correlations in a quasi-2D system.

Contribution

It provides a detailed analysis of vortex formation, quantum phase transitions, and correlations in rotating Bose gases using beyond lowest-Landau-level approximation and exact diagonalization.

Findings

Identification of stable and unstable angular momentum states.

Visualization of vortex patterns with discrete rotational symmetry.

Analysis of quantum correlations and entanglement in many-body states.

Abstract

We present the exact diagonalization study of rotating Bose-condensed gas interacting via finite-range Gaussian potential confined in a quasi-2D harmonic trap. The system of many-body Hamiltonian matrix is diagonalized in given subspaces of quantized total angular momentum to obtain the lowest-energy eigenstate employing the beyond lowest-Landau-level approximation. In the co-rotating frame, the quantum mechanical stability of angular momentum states is discussed for the existence of phase transition between the stable states of interacting system. Thereby analyzing the von Neumann entanglement entropy and degree of condensation provide the information about quantum phase correlation in the many-body states. Calculating the conditional probability distribution, we further probe the internal structure of quantum mechanically stable and unstable states. Much emphasis is put on finding the spatial correlation of bosonic atoms in the rotating system for the formation and entry of singly quantized vortices, and then organizing into canonical polygons with and without a central vortex at the trap center. Results are summarized in the form of a movie depicting the vortex patterns having discrete p-fold rotational symmetry with $p = 2,3,4,5,6$.