FACt: FORTRAN toolbox for calculating fluctuations in atomic condensates

TL;DR

FACt is a FORTRAN toolbox designed to calculate quantum and thermal fluctuations in two-component Bose-Einstein condensates by solving the Bogoliubov-de Gennes equations self-consistently, aiding in the analysis of various physical properties.

Contribution

The paper introduces a versatile FORTRAN code that efficiently computes fluctuations and excitation spectra in TBECs, adaptable for multiple physical property calculations.

Findings

Successfully computes ground state density profiles.

Accurately determines low energy excitation modes.

Facilitates analysis of experimental observables.

Abstract

We develop a FORTRAN code to compute fluctuations in atomic condensates (FACt) by solving the Bogoliubov-de Gennes (BdG) equations for two component Bose-Einstein condensate (TBEC) in quasi two dimensions. The BdG equations are recast as matrix equations and solved self consistently. The code is suitable for handling quantum fluctuations as well as thermal fluctuations at temperatures below the critical point of Bose-Einstein condensation. The code is versatile, and the ground state density profile and low energy excitation modes obtained from the code can be easily adapted to compute different properties of TBECs -- ground state energy, overlap integral, quasi particle amplitudes of BdG spectrum, dispersion relation and structure factor and other related experimental observables.