The European Physical Journal B

, Volume 68, Issue 3, pp 445–452 | Cite as

Probing the thermal atoms of a Bose gas through Raman transition

Article

Abstract

We explore the many body physics of a Bose condensed atom gas at finite temperature through the Raman transition between two hyperfine levels. Unlike the Bragg scattering where the phonon-like nature of the collective excitations has been observed, a different branch of thermal atom excitation is found theoretically in the Raman scattering. This excitation is predicted in the generalized random phase approximation (GRPA) and has a gapped and parabolic dispersion relation. The gap energy results from the exchange interaction and is released during the Raman transition. The scattering rate is determined versus the transition frequency ω and the transferred momentum q and shows the corresponding resonance around this gap. Nevertheless, the Raman scattering process is attenuated by the superfluid part of the gas. The macroscopic wave function of the condensate deforms its shape in order to screen locally the external potential displayed by the Raman light beams. This screening is total for a condensed atom transition in order to prevent the condensate from incoherent scattering. The experimental observation of this result would explain some of the reasons why asuperfluid condensate moves coherentlywithout any friction with its surrounding.

PACS

03.75.Hh Static properties of condensates; thermodynamical, statistical, and structural properties 03.75.Kk Dynamic properties of condensates; collective and hydrodynamic excitations, superfluid flow 05.30.-d Quantum statistical mechanics 

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References

  1. P. Szépfalusy, I. Kondor, Ann. Phys. 82, 1 (1974); A. Minguzzi, M.P. Tozi, J. Phys.: Cond. Matter 9, 10211 (1997); M. Fliesser, J. Reidl, P. Szépfalusy, R. Graham, Phys. Rev. A 64, 013609 (2001); J. Reidl, A. Csordas, R. Graham, P. Szépfalusy, Phys. Rev. A 61, 043606 (2000)Google Scholar
  2. C.-H. Zhang, H.A. Fertig, Phys. Rev. A 74, 023613 (2006); C.-H. Zhang, H.A. Fertig, Phys. Rev. A 75, 013601 (2007)Google Scholar
  3. P. Navez, J. Low. Temp. Phys. 138, 705 (2005); P. Navez, Physica A 356, 241 (2005); P. Navez, R. Graham, Phys. Rev. A 73, 043612 (2006)Google Scholar
  4. M.Ö. Oktel, L.S. Levitov, Phys. Rev. Lett. 83, 1 (1999); M.Ö. Oktel, L.S. Levitov, Phys. Rev. A 65, 063604 (2002); M.Ö. Oktel, T.C. Killian, D. Kleppner, L.S. Levitov, Phys. Rev. A 65, 033617 (2002); M.Ö. Oktel, L.S. Levitov, Phys. Rev. Lett. 88, 230403 (2002)Google Scholar
  5. P. Navez, Physica A 387, 4070 (2008)Google Scholar
  6. A. Griffin, Phys. Rev. B 53, 9341 (1996); P.C. Hohenberg, P.C. Martin, Ann. Phys. (N.Y.) 34, 291 (1965); A. Griffin, Excitations in a Bose-Condensed Liquid (University Press, Cambridge, 1993)Google Scholar
  7. N.M. Hugenholtz, D. Pines, Phys. Rev. 116, 489 (1959)Google Scholar
  8. D.M. Stamper-Kurn, A.P. Chikkatur, A. Görlitz, S. Inouye, S. Gupta, D.E. Pritchard, W. Ketterle, Phys. Rev. Lett. 83, 2876 (1999)Google Scholar
  9. F. Zambelli, L. Pitaevskii, D.M. Stamper-Kurn, S. Stringari, Phys. Rev. A 61, 063608 (2000); R. Ozeri, N. Katz, J. Steinhauer, N. Davidson, Rev. Mod. Phys. 77, 187 (2005)Google Scholar
  10. A.J. Leggett, Rev. Mod. Phys. 73, 307 (2001); L. Pitaevskii, S. Stringari, Bose-Einstein Condensation (Clarendon Press, 2003); C.J. Pethick, H. Smith, Bose-Einstein Condensation in Dilute Gases (Cambridge University Press, 2001)Google Scholar
  11. A.J. Leggett, Rev. Mod. Phys. 71, S318 (1999)Google Scholar
  12. A.P. Chikkatur, A. Görlitz, D.M. Stamper-Kurn, S. Inouye, S. Gupta, W. Ketterle, Phys. Rev. Lett. 85, 483 (2000)Google Scholar
  13. F.S. Cataliotti, S. Burger, C. Fort, P. Maddaloni, F. Minardi, A. Trombettoni, A. Smerzi, M. Inguscio, Science 293, 843 (2001)Google Scholar
  14. D.A. Huse, E.D. Siggia, J. Low. Temp. Phys. 46, 137 (1981)Google Scholar
  15. D. Pines, P. Nozières, The Theory of Quantum Liquids (Addison-Wesley, Readin, MA, 1989), Vol. I, IIGoogle Scholar
  16. A. Montina, Phys. Rev. A 67, 053614 (2003); A. Montina, Phys. Rev. A 66, 023609 (2002)Google Scholar
  17. W.B. Colson, A.L. Fetter, J. Low Temp. Phys. 33, 231 (1978); W. Zhang, D.L. Zhou, M.-S. Chang, M.S. Chapman, L. You, Phys. Rev. Lett. 95, 180403 (2005)Google Scholar

Copyright information

© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  1. 1.Katholieke Universiteit LeuvenHeverleeBelgium
  2. 2.Universitaet Duisburg-EssenDuisburgGermany

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