Quantum phase transition of condensed bosons in optical lattices

TL;DR

This paper investigates the quantum phase transition between superfluid and Mott-insulator states in ultracold bosonic gases within optical lattices, using Green functions and Bogoliubov transformations to analyze the transition mechanism and energy spectrum.

Contribution

It provides a detailed analysis of the superfluid-Mott-insulator transition mechanism based on energy-band structure and Bogoliubov theory, offering explicit explanations of the superfluid phase.

Findings

Transition condition linked to energy-band structure

Explicit superfluid phase explanation from energy spectrum

Theoretical framework for phase transition analysis

Abstract

In this paper we study the superfluid-Mott-insulator phase transition of ultracold dilute gas of bosonic atoms in an optical lattice by means of Green function method and Bogliubov transformation as well. The superfluid- Mott-insulator phase transition condition is determined by the energy-band structure with an obvious interpretation of the transition mechanism. Moreover the superfluid phase is explained explicitly from the energy spectrum derived in terms of Bogliubov approach.