First and Second Sound in Cylindrically Trapped Gases

G. Bertaina, L. Pitaevskii, and S. Stringari
Phys. Rev. Lett. 105, 150402 – Published 4 October 2010

Abstract

We investigate the propagation of density and temperature waves in a cylindrically trapped gas with radial harmonic confinement. Starting from two-fluid hydrodynamic theory we derive effective 1D equations for the chemical potential and the temperature which explicitly account for the effects of viscosity and thermal conductivity. Differently from quantum fluids confined by rigid walls, the harmonic confinement allows for the propagation of both first and second sound in the long wavelength limit. We provide quantitative predictions for the two sound velocities of a superfluid Fermi gas at unitarity. For shorter wavelengths we discover a new surprising class of excitations continuously spread over a finite interval of frequencies. This results in a nondissipative damping in the response function which is analytically calculated in the limiting case of a classical ideal gas.

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  • Received 29 January 2010

DOI:https://doi.org/10.1103/PhysRevLett.105.150402

© 2010 The American Physical Society

Authors & Affiliations

G. Bertaina1, L. Pitaevskii1,2, and S. Stringari1

  • 1INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, I-38123 Povo, Trento, Italy
  • 2Kapitza Institute for Physical Problems, Kosygina 2, 119334 Moscow, Russia

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Issue

Vol. 105, Iss. 15 — 8 October 2010

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