Bragg spectroscopy of discrete axial quasiparticle modes in a cigar-shaped degenerate Bose gas

TL;DR

This paper proposes an experimental method using two-photon Bragg scattering to observe long wavelength axial quasiparticle modes in a cigar-shaped Bose-Einstein condensate, extending previous short wavelength phonon observations.

Contribution

It introduces a detailed experimental setup and parameter values for observing discrete axial modes in a 3D BEC using Bragg spectroscopy, which was not previously demonstrated.

Findings

Identifies conditions for observing long wavelength axial modes.

Provides specific parameters for momentum, energy, and interaction strength.

Suggests the experimental feasibility under dilute conditions.

Abstract

We propose an experiment in which long wavelength discrete axial quasiparticle modes can be imprinted in a 3D cigar-shaped Bose-Einstein condensate by using two-photon Bragg scattering experiments, similar to the experiment at the Weizmann Institute [J. Steinhauer {\em et al.}, Phys. Rev. Lett. {\bf 90}, 060404 (2003)] where short wavelength axial phonons with different number of radial modes have been observed. We provide values of the momentum, energy and time duration of the two-photon Bragg pulse and also the two-body interaction strength which are needed in the Bragg scattering experiments in order to observe the long wavelength discrete axial modes. These discrete axial modes can be observed when the system is dilute and the time duration of the Bragg pulse is long enough.