Finite-temperature effects on the superfluid Bose-Einstein condensation of confined ultracold atoms in three-dimensional optical lattices

TL;DR

This paper investigates how finite temperatures influence the superfluid phase transition of ultracold bosonic atoms in three-dimensional optical lattices using a quantum rotor approach within the Bose-Hubbard model.

Contribution

It introduces a rotor-based effective action formalism to analyze finite-temperature effects on superfluidity in strongly correlated Bose-Hubbard systems.

Findings

Mapped the finite-temperature phase diagram of the 3D Bose-Hubbard model

Identified the role of rotor phase variables in superfluid transition

Provided a framework for studying temperature and interaction effects

Abstract

We discuss the finite-temperature phase diagram in the three-dimensional Bose-Hubbard (BH) model in the strong correlation regime, relevant for Bose-Einstein condensates in optical lattices, by employing a quantum rotor approach. In systems with strong on site repulsive interactions, the rotor U(1) phase variable dual to the local boson density emerges as an important collective field. After establishing the connection between the rotor construction and the the on--site interaction in the BH model the robust effective action formalism is developed which allows us to study the superfluid phase transition in various temperature--interaction regimes.