Hugenholtz -- Pines relations and the critical temperature of a Rabi coupled binary Bose system

TL;DR

This paper uses a Gaussian approximation to analyze a Rabi coupled binary Bose system, deriving extended Hugenholtz-Pines relations and studying how Rabi coupling influences the critical temperature of Bose-Einstein condensation.

Contribution

It introduces extended Hugenholtz-Pines relations accounting for Rabi coupling and quantifies the maximum shift in critical temperature due to this interaction.

Findings

The critical temperature shift cannot exceed approximately 60%.

The shift approaches a plateau as the Rabi coupling increases.

The temperature shift is always positive, regardless of interaction sign.

Abstract

Using a theoretical field Gaussian approximation we have studied Rabi coupled binary Bose system at low temperatures. We have derived extended Hugenholtz - Pines relations taking into account one body interaction (e.g. Rabi coupling) and studied the critical temperature $T_c$ of Bose-Einstein condensate transition. We have shown that, the shift of $T_c$ due to this interaction can not exceed $\sim 60 \%$ and goes to a plateau with increasing the parameter $\Omega_R/T_{c}^{0}$, where $\Omega_R$ is the intensity of the coupling and $T_{c}^{0}$ is the critical temperature of the system with $\Omega_R=0$. Moreover, the shift is always positive and does not depend on the sign of the one body interaction.