Effect of finite range interactions on roton mode softening in a multi-component BEC

TL;DR

This paper investigates how finite-range interactions influence roton mode softening in multi-component Bose-Einstein Condensates, revealing that increasing components allows softer roton modes at lower interaction strengths, potentially reducing three-body losses.

Contribution

It demonstrates that multi-component BECs enable roton mode softening at lower gas parameters, offering a new way to control interactions and minimize losses.

Findings

Roton mode softening occurs at lower gas parameters with more components.

Multi-component BECs can reduce three-body losses during roton softening.

Finite-range interactions significantly affect excitation spectra.

Abstract

We consider the Gross-Pitaevskii(GP) model of a Bose-Einstein Condensate(BEC) for single-component and multi-component BEC. The pseudopotential for s-wave scattering between atoms is taken to be of width of the order of the s-wave scattering length. Such an interaction giving rise to a roton minimum in the spectrum of elementary excitations of a single component BEC is well known. However, softening roton modes takes us in the strongly interacting BEC regime where three body losses occur. We study the roton mode softening for a multi-component BEC. We show that by increasing the number of components of a multi-component BEC, the roton mode can be softened at a progressively lower value of the gas parameter ($a^{3}n$), thus reducing three body losses.