Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1611.06351 · Journal of Physics B Atomic Molecular and Optical Physics

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

Abhijit Pendse

Published Mar 5, 2018• 5 citations
arXivHTMLPDF

Abstract

Abstract We consider the Gross-Pitaevskii 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 a 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 take us into 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 the three body losses.

DOI
10.1088/1361-6455/aab413

Related papers

Roton mode softening in a multi-component BEC

Abhijit Pendse

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. We study this roton minimum for a multi-component BECs. We show that for a fixed inter-species scattering length, roton mode can be softened by increasing the number of distinct components of a multi-component BEC.

•Nov 19, 2016•0 citations

Roton-Type Mode Softening in a Quantum Gas with Cavity-Mediated Long-Range Interactions

Rafael Mottl, Ferdinand Brennecke, Kristian Baumann +3 more

Long-range interactions in quantum gases are predicted to give rise to an excitation spectrum of roton character, similar to that observed in superfluid helium. We investigated the excitation spectrum of a Bose-Einstein condensate with cavity-mediated long-range interactions, which couple all particles to each other. Increasing the strength of the interaction leads to a softening of an excitation mode at a finite momentum, preceding a superfluid-to-supersolid phase transition. We used a variant of Bragg spectroscopy to study the mode softening across the phase transition. The measured spectrum was in very good agreement with ab initio calculations and, at the phase transition, a diverging susceptibility was observed. The work paves the way toward quantum simulation of long-range interacting many-body systems.

arXiv:1203.1322•Science•May 18, 2012•292 citations

Short-wave excitations in non-local Gross-Pitaevskii model

A. P. Ivashin, Yuri M. Poluektov

Abstract We show that a non-local form of the Gross-Pitaevskii equation describes not only long-wave excitations, but also the short-wave ones in Bose-condensate systems. At certain parameter values, the excitation spectrum mimics the Landau spectrum of quasi-particle excitations in superfluid helium with roton minimum. The excitation wavelength, at which the roton minimum exists, is close to the inter-particle interaction range. We determine how the roton gap and the effective roton mass depend on the interaction potential parameters, and show that the existence domain of the spectrum with a roton minimum is reduced if one accounts for an inter-particle attraction.

arXiv:1004.0442•Open Physics•Nov 25, 2010•5 citations

Atomic Bose–Einstein condensation with three-body interactions and collective excitations

The stability of a Bose–Einstein condensed state of trapped ultra-cold atoms is investigated under the assumption of an attractive two-body and a repulsive three-body interaction. The Ginzburg–Pitaevskii–Gross (GPG) nonlinear Schrödinger equation is extended to include an effective potential dependent on the square of the density and solved numerically for the s-wave. The lowest collective mode excitations are determined and their dependences on the number of atoms and on the strength of the three-body force are studied. The addition of three-body dynamics can allow the number of condensed atoms to increase considerably, even when the strength of the three-body force is very small compared with the strength of the two-body force. We study in detail the first-order liquid–gas phase transition for the condensed state, which can happen in a critical range of the effective three-body force parameter. 1.

•Jan 1, 2000•0 citations

Softening of Roton and Phonon Modes in a Bose-Einstein Condensate with Spin-Orbit Coupling

Si-Cong Ji, Long Zhang, Xiaotian Xu +4 more

Roton-type excitations usually emerge from strong correlations or long-range interactions, as in superfluid helium or dipolar ultracold atoms. However, in a weakly short-range interacting quantum gas, the recently synthesized spin-orbit (SO) coupling can lead to various unconventional phases of superfluidity and give rise to an excitation spectrum of roton-maxon character. Using Bragg spectroscopy, we study a SO-coupled Bose-Einstein condensate of ^{87}Rb atoms and show that the excitation spectrum in a "magnetized" phase clearly possesses a two-branch and roton-maxon structure. As Raman coupling strength Ω is decreased, a roton-mode softening is observed, as a precursor of the phase transition to a stripe phase that spontaneously breaks spatially translational symmetry. The measured roton gaps agree well with theoretical calculations. Furthermore, we determine sound velocities both in the magnetized and in the nonmagnetized phases, and a phonon-mode softening is observed around the phase transition in between. The validity of the f-sum rule is examined.

arXiv:1408.1755•Physical Review Letters•Mar 9, 2015•148 citations

Atomic Bose-Einstein condensation with three-body interactions and collective excitations

A. Gammal, T. Frederico, Lauro Tomio +1 more

The stability of a Bose-Einstein condensed state of trapped ultra-cold atoms is investigated under the assumption of an attractive two-body and a repulsive three-body interaction. The Ginzburg-Pitaevskii-Gross (GPG) nonlinear Schrödinger equation is extended to include an effective potential dependent on the square of the density and solved numerically for the s-wave. The lowest collective mode excitations are determined and their dependences on the number of atoms and on the strength of the three-body force are studied. The addition of three-body dynamics can allow the number of condensed atoms to increase considerably, even when the strength of the three-body force is very small compared with the strength of the two-body force. We study in detail the first-order liquid-gas phase transition for the condensed state, which can happen in a critical range of the effective three-body force parameter.

arXiv:cond-mat/9911089•Journal of Physics B Atomic Molecular and Optical Physics•Sep 15, 2000•127 citations
Abstract We consider the Gross-Pitaevskii 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 a 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 take us into 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 the three body losses.
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. We study this roton minimum for a multi-component BECs. We show that for a fixed inter-species scattering length, roton mode can be softened by increasing the number of distinct components of a multi-component BEC.
Long-range interactions in quantum gases are predicted to give rise to an excitation spectrum of roton character, similar to that observed in superfluid helium. We investigated the excitation spectrum of a Bose-Einstein condensate with cavity-mediated long-range interactions, which couple all particles to each other. Increasing the strength of the interaction leads to a softening of an excitation mode at a finite momentum, preceding a superfluid-to-supersolid phase transition. We used a variant of Bragg spectroscopy to study the mode softening across the phase transition. The measured spectrum was in very good agreement with ab initio calculations and, at the phase transition, a diverging susceptibility was observed. The work paves the way toward quantum simulation of long-range interacting many-body systems.
Abstract We show that a non-local form of the Gross-Pitaevskii equation describes not only long-wave excitations, but also the short-wave ones in Bose-condensate systems. At certain parameter values, the excitation spectrum mimics the Landau spectrum of quasi-particle excitations in superfluid helium with roton minimum. The excitation wavelength, at which the roton minimum exists, is close to the inter-particle interaction range. We determine how the roton gap and the effective roton mass depend on the interaction potential parameters, and show that the existence domain of the spectrum with a roton minimum is reduced if one accounts for an inter-particle attraction.
The stability of a Bose–Einstein condensed state of trapped ultra-cold atoms is investigated under the assumption of an attractive two-body and a repulsive three-body interaction. The Ginzburg–Pitaevskii–Gross (GPG) nonlinear Schrödinger equation is extended to include an effective potential dependent on the square of the density and solved numerically for the s-wave. The lowest collective mode excitations are determined and their dependences on the number of atoms and on the strength of the three-body force are studied. The addition of three-body dynamics can allow the number of condensed atoms to increase considerably, even when the strength of the three-body force is very small compared with the strength of the two-body force. We study in detail the first-order liquid–gas phase transition for the condensed state, which can happen in a critical range of the effective three-body force parameter. 1.
Roton-type excitations usually emerge from strong correlations or long-range interactions, as in superfluid helium or dipolar ultracold atoms. However, in a weakly short-range interacting quantum gas, the recently synthesized spin-orbit (SO) coupling can lead to various unconventional phases of superfluidity and give rise to an excitation spectrum of roton-maxon character. Using Bragg spectroscopy, we study a SO-coupled Bose-Einstein condensate of ^{87}Rb atoms and show that the excitation spectrum in a "magnetized" phase clearly possesses a two-branch and roton-maxon structure. As Raman coupling strength Ω is decreased, a roton-mode softening is observed, as a precursor of the phase transition to a stripe phase that spontaneously breaks spatially translational symmetry. The measured roton gaps agree well with theoretical calculations. Furthermore, we determine sound velocities both in the magnetized and in the nonmagnetized phases, and a phonon-mode softening is observed around the phase transition in between. The validity of the f-sum rule is examined.
The stability of a Bose-Einstein condensed state of trapped ultra-cold atoms is investigated under the assumption of an attractive two-body and a repulsive three-body interaction. The Ginzburg-Pitaevskii-Gross (GPG) nonlinear Schrödinger equation is extended to include an effective potential dependent on the square of the density and solved numerically for the s-wave. The lowest collective mode excitations are determined and their dependences on the number of atoms and on the strength of the three-body force are studied. The addition of three-body dynamics can allow the number of condensed atoms to increase considerably, even when the strength of the three-body force is very small compared with the strength of the two-body force. We study in detail the first-order liquid-gas phase transition for the condensed state, which can happen in a critical range of the effective three-body force parameter.