A study of coherently coupled two-component Bose-Einstein Condensates

TL;DR

This paper investigates the phase transition and excitation properties of coherently coupled two-component Bose-Einstein condensates, highlighting the effects of spin-flipping coupling and trapping potentials on their ground states and phase behavior.

Contribution

It provides a self-consistent analysis of phase transitions, excitation spectra, and ground state configurations in coherently coupled BECs, including effects of optical lattices and trapping potentials.

Findings

Spin-flipping coupling converts the transition to second order.

Excitation spectrum and structure factor change across the transition.

Optical lattices lead to new ground state configurations.

Abstract

We present a self-consistent study of coherently coupled two-component Bose-Einstein condensates. Finite spin-flipping coupling changes the first order demixing phase transition for Bose-Bose mixtures to a second order phase transition between an unpolarized and a polarized state. We analise the excitation spectrum and the structure factor along the transition for a homogeneous system. We discuss the main differences at the transition between a coherent coupled gas and a two-component mixture. We finally study the ground state when spin-(in)dependent trapping potentials are added to the system, focusing on optical lattices, which give rise to interesting new configurations.