Phase diagram of semi-hard-core bosons on a square lattice

TL;DR

This paper explores the phase diagram of semi-hard-core bosons on a square lattice using mean field theory, revealing how local correlations influence phase transitions and critical phenomena.

Contribution

It introduces a detailed analysis of how local correlation parameters alter the phase diagram and transition types in semi-hard-core boson systems.

Findings

Transition from hard-core to semi-hard-core behavior with local correlations

Parabolic dependence of critical temperature on boson concentration

Emergence of new phase transitions and critical points

Abstract

Phase diagrams of charged semi-hard-core bosons are studied in the mean field approximation. An increase in the parameter of local correlations is shown to lead to the transformation of the phase diagram of the system from the form characteristic of hard-core bosons to the limiting form with a parabolic dependence of the critical temperature of charge ordering on the boson concentration. The evolution between these limiting cases is dependent on the ratio between the model parameters and is accompanied by various effects, such as the change in the phase transition type, the appearance of new order-order transition, and the appearance of new critical points.