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:cond-mat/0207158 · Physical Review A

Scissors mode of an expanding Bose-Einstein condensate

Michele Modugno, Giovanni Carlo Modugno, G. Roati, C. Fort, M. Inguscio

Published Feb 24, 2003• 22 citations
arXivHTMLPDF

Abstract

We study the scissors mode of a free-expanding Bose-Einstein condensate. We find that the irrotational character of the superfluid flow within the condensate has dramatic consequences on the evolution of the scissors oscillation. After a short expansion the oscillation is amplified and distorted, while asymptotically it recovers its initial sinusoidal behavior, with an enhanced amplitude. We investigate this phenomenon by using a technique to excite the scissors mode in a condensate held in a magnetostatic potential.

DOI
10.1103/physreva.67.023608

Related papers

Scissors Mode and Superfluidity of a Trapped Bose-Einstein Condensed Gas

David Guéry-Odelin, S. Stringari

We investigate the oscillation of a dilute atomic gas generated by a sudden rotation of the confining trap (scissors mode). This oscillation reveals the effects of superfluidity exhibited by a Bose-Einstein condensate. The scissors mode is also investigated in a classical gas above ${T}_{c}$ in various collisional regimes. The crucial difference with respect to the superfluid case arises from the occurrence of low frequency components, which are responsible for the rigid value of the moment of inertia. Different experimental procedures to excite the scissors mode are discussed.

arXiv:cond-mat/9907293•Physical Review Letters•Nov 29, 1999•175 citations

Observation of the Scissors Mode and Evidence for Superfluidity of a Trapped Bose-Einstein Condensed Gas

Onofrio M. Maragò, S. A. Hopkins, J. Arlt +3 more

We report the observation of the scissors mode of a Bose-Einstein condensed gas of 87Rb atoms in a magnetic trap, which gives direct evidence of superfluidity in this system. The scissors mode of oscillation is excited by a sudden rotation of the anisotropic trapping potential. For a gas above T(c) (normal fluid) we detect the occurrence of oscillations at two frequencies, with the lower frequency corresponding to the rigid body value of the moment of inertia. Well below T(c) the condensate oscillates at a single frequency, without damping, as expected for a superfluid.

arXiv:cond-mat/9911195•Physical Review Letters•Mar 6, 2000•270 citations

Consequence of Superfluidity on the Expansion of a Rotating Bose-Einstein Condensate

Mark Edwards, Charles W. Clark, P. Pedri +2 more

We propose an easily detectable signature of superfluidity in rotating, vortex-free gaseous Bose-Einstein condensates. We have studied the time evolution of the expansion of such a condensate after it is released from the confining trap. We find that if such a condensate is not initially rotating, then at some moment it will instantaneously achieve a circular cross section. If the condensate is initially rotating its irrotational flow and the conservation of angular momentum prevent the released condensate from attaining a circular cross section, since the instantaneous moment of inertia is then proportional to the asymmetry of this cross section.

arXiv:cond-mat/0106080•Physical Review Letters•Jan 31, 2002•27 citations

Nonlinear coupling between scissors modes of a Bose-Einstein condensate

Usama Al Khawaja, Henk T. C. Stoof

We explore the nonlinear coupling of the three scissors modes of an anisotropic Bose-Einstein condensate. We show that only when the frequency of one of the scissors modes is twice the frequency of another scissors mode, these two modes can be resonantly coupled and a down-conversion can occur. We perform the calculation variationally using a gaussian trial wave function. This enables us to obtain simple analytical results that describe the oscillation and resonance behavior of the two coupled modes.

arXiv:cond-mat/0107567•Physical Review A•Dec 12, 2001•17 citations

Experimental Observation of Beliaev Coupling in a Bose-Einstein Condensate

E. Hodby, Onofrio M. Maragò, Gerald Hechenblaikner +1 more

We report the first experimental observation of Beliaev coupling between collective excitations of a Bose-Einstein condensed gas. Beliaev coupling is not predicted by the Gross-Pitaevskii equation and so this experiment tests condensate theory beyond the mean field approximation. Measurements of the amplitude of a high frequency scissors mode show that the Beliaev process transfers energy to a lower-lying mode and then back and forth between these modes, unlike Landau processes which lead to a monotonic decrease in amplitude. To enhance the Beliaev process we adjusted the geometry of the magnetic trapping potential to give a frequency ratio of 2 to 1 between the two scissors modes.

arXiv:cond-mat/0010157•Physical Review Letters•Mar 12, 2001•79 citations

Direct Observation of Irrotational Flow and Evidence of Superfluidity in a Rotating Bose-Einstein Condensate

Gerald Hechenblaikner, E. Hodby, S. A. Hopkins +2 more

We have observed the expansion of vortex-free, rotating Bose condensates after their sudden release from a slowly rotating anisotropic trap. Conservation of angular momentum, combined with the constraint of irrotational flow, cause the rotating condensate to expand in a distinctively different way to one released from a static (nonrotating) trap. This difference provides clear experimental evidence of the purely irrotational velocity field associated with a superfluid. We observed this behavior in absorption images taken along the rotation axis.

arXiv:cond-mat/0106182•Physical Review Letters•Jan 31, 2002•49 citations
We study the scissors mode of a free-expanding Bose-Einstein condensate. We find that the irrotational character of the superfluid flow within the condensate has dramatic consequences on the evolution of the scissors oscillation. After a short expansion the oscillation is amplified and distorted, while asymptotically it recovers its initial sinusoidal behavior, with an enhanced amplitude. We investigate this phenomenon by using a technique to excite the scissors mode in a condensate held in a magnetostatic potential.
We investigate the oscillation of a dilute atomic gas generated by a sudden rotation of the confining trap (scissors mode). This oscillation reveals the effects of superfluidity exhibited by a Bose-Einstein condensate. The scissors mode is also investigated in a classical gas above Tc{T}_{c}Tc​ in various collisional regimes. The crucial difference with respect to the superfluid case arises from the occurrence of low frequency components, which are responsible for the rigid value of the moment of inertia. Different experimental procedures to excite the scissors mode are discussed.
We report the observation of the scissors mode of a Bose-Einstein condensed gas of 87Rb atoms in a magnetic trap, which gives direct evidence of superfluidity in this system. The scissors mode of oscillation is excited by a sudden rotation of the anisotropic trapping potential. For a gas above T(c) (normal fluid) we detect the occurrence of oscillations at two frequencies, with the lower frequency corresponding to the rigid body value of the moment of inertia. Well below T(c) the condensate oscillates at a single frequency, without damping, as expected for a superfluid.
We propose an easily detectable signature of superfluidity in rotating, vortex-free gaseous Bose-Einstein condensates. We have studied the time evolution of the expansion of such a condensate after it is released from the confining trap. We find that if such a condensate is not initially rotating, then at some moment it will instantaneously achieve a circular cross section. If the condensate is initially rotating its irrotational flow and the conservation of angular momentum prevent the released condensate from attaining a circular cross section, since the instantaneous moment of inertia is then proportional to the asymmetry of this cross section.
We explore the nonlinear coupling of the three scissors modes of an anisotropic Bose-Einstein condensate. We show that only when the frequency of one of the scissors modes is twice the frequency of another scissors mode, these two modes can be resonantly coupled and a down-conversion can occur. We perform the calculation variationally using a gaussian trial wave function. This enables us to obtain simple analytical results that describe the oscillation and resonance behavior of the two coupled modes.
We report the first experimental observation of Beliaev coupling between collective excitations of a Bose-Einstein condensed gas. Beliaev coupling is not predicted by the Gross-Pitaevskii equation and so this experiment tests condensate theory beyond the mean field approximation. Measurements of the amplitude of a high frequency scissors mode show that the Beliaev process transfers energy to a lower-lying mode and then back and forth between these modes, unlike Landau processes which lead to a monotonic decrease in amplitude. To enhance the Beliaev process we adjusted the geometry of the magnetic trapping potential to give a frequency ratio of 2 to 1 between the two scissors modes.
We have observed the expansion of vortex-free, rotating Bose condensates after their sudden release from a slowly rotating anisotropic trap. Conservation of angular momentum, combined with the constraint of irrotational flow, cause the rotating condensate to expand in a distinctively different way to one released from a static (nonrotating) trap. This difference provides clear experimental evidence of the purely irrotational velocity field associated with a superfluid. We observed this behavior in absorption images taken along the rotation axis.