Advertisement

Quantum Degeneracy in Lithium Gases

Chapter
  • 203 Downloads
Part of the NATO Science Series book series (NAII, volume 51)

Abstract

Lithium is an attractive atom for studies of quantum degenerate gases because its two naturally occurring isotopes, 6Li and 7Li, have opposite exchange symmetry and have stable nuclei. Since 6Li is composed of an odd number of spin-1/2 particles (3 electrons, 3 protons, 3 neutrons), it is itself a half-integer composite particle obeying Fermi-Dirac statistics. On the other hand, 7Li with its extra neutron is a composite boson. The phenomena exhibited by each isotope, therefore, should be vastly different at ultra-low temperatures, where effects of quantum degeneracy are manifested. For example, we have shown that 7Li undergoes Bose-Einstein condensation (BEC) [1], the paradigm of all quantum statistical phase transitions. A gas of 6Li, conversely, cannot directly Bose condense, although they can undergo a BEC-like phase transition in which particles form ‘Cooper pairs’. This effect is responsible for electronic superconductivity and for superfluidity of 3He.

Keywords

Attractive Interaction Evaporative Cool Magnetic Trap Trap Atom Nonlinear Schrodinger Equation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Bradley, C.C., Sackett, C.A., Tollett, J.J., and Hulet, R.G. (1995) Evidence of Bose-Einstein Condensation in an Atomic Gas with Attractive Interactions, Phys. Rev. Lett. 75, 1687.ADSCrossRefGoogle Scholar
  2. 2.
    Huang, K. (1987). Statistical Mechanics, John Wiley and Sons, New York.zbMATHGoogle Scholar
  3. 3.
    Fried, D.G., Killian, T.C., Willmann, L., Landhuis, D., Moss, S.C., Kleppner, D., and Greytak, T.J. (1998) Bose-Einstein condensation of atomic hydrogen, Phys. Rev. Lett. 81, 3811–3814.ADSCrossRefGoogle Scholar
  4. 4.
    Dalfovo, F., Giorgini, S., Pitaevskii, L.P., and Stringari, S. (1999) Theory of Bose-Einstein condensation in trapped gases, Rev. Mod Phys. 71, 463–512.ADSCrossRefGoogle Scholar
  5. 5.
    Weiner, J., Bagnato, V., Zilio, S., and Julienne, P.S. (1999) Experiments and Theory in Cold and Ultracold Collisions, Rev. Mod. Phys. 71, 1–85.ADSCrossRefGoogle Scholar
  6. 6.
    Abraham, E.R.I., McAlexander, W.I., Sackett, C.A., and Hulet, R.G. (1995) Spectroscopic Determination of the S-Wave Scattering Length of Lithium, Phys. Rev. Lett. 74, 1315–1318.ADSCrossRefGoogle Scholar
  7. 7.
    Abraham, E.R.I., McAlexander, W.I., Gerton, J.M., Hulet, R.G., Cote, R., and Dalgarno, A. (1997) Triplet s-wave resonance in 6Li collisions and scattering lengths of 6Li and 7Li, Phys. Rev. A 55, R3299-3302.Google Scholar
  8. 8.
    Tsai, C.C., Freeland, R.S., Vogels, J.M., Boesten, H.M.J.M., Verhaar, B.J., and Heinzen, D.J. (1997) Two-Color Photoassociation Spectroscopy of Ground State Rb2, Phys. Rev. Lett. 79, 1245–1248.ADSCrossRefGoogle Scholar
  9. 9.
    Bogoliubov, N. (1947) On the Theory of Superfluidity, Journal of Physics (USSR) 11, 23–32.Google Scholar
  10. 10.
    Stoof, H.T.C. (1994) Atomic Bose gas with a negative scattering length, Phys. Rev. A 49, 3824–3830.ADSCrossRefGoogle Scholar
  11. 11.
    Bradley, C.C., Sackett, C.A., and Hulet, R.G. (1997) Bose-Einstein Condensation of Lithium: Observation of Limited Condensate Number, Phys. Rev. Lett. 78, 985–989.ADSCrossRefGoogle Scholar
  12. 12.
    Ruprecht, P.A., Holland, M.J., Burnett, K., and Edwards, M. (1995) Time-dependent solution of the nonlinear Schrodinger equation for Bose-condensed trapped neutral atoms, Phys. Rev. A 51, 4704.ADSCrossRefGoogle Scholar
  13. 13.
    Sackett, C.A., Bradley, C.C., Welling, M., and Hulet, R.G. (1997) Bose-Einstein Condensation of Lithium, Appl. Phys. B 65, 433–440.ADSCrossRefGoogle Scholar
  14. 14.
    Baym, G. and Pethick, C.J. (1996) Ground-State Properties of Magnetically Trapped Bose-Condensed Rubidium Gas, Phys. Rev. Lett. 76, 6–9.ADSCrossRefGoogle Scholar
  15. 15.
    Stoof, H.T.C. (1997) Macroscopic Quantum Tunneling of a Bose Condensate, J. Stat. Phys. 87, 1353–136ADSCrossRefGoogle Scholar
  16. 16.
    Tollett, J.J., Bradley, C.C., Sackett, C.A., and Hulet, R.G. (1995) Permanent Magnet Trap for Cold Atoms, Phys. Rev. A 51, R22–R25.ADSCrossRefGoogle Scholar
  17. 17.
    PŐrez-GarcŠa, V., Michinel, H., Cirac, J.I., Lewenstein, M., and Zoller, R (1997) Dynamics of Bose-Einstein condensates: Variational solutions of the Gross-Pitaevskii equations, Phys. Rev. A 56, 1424–1432.ADSCrossRefGoogle Scholar
  18. 18.
    Sackett, C.A., Bradley, C.C., and Hulet, R.G. (1997) Optimization of Evaporative Cooling, Phys. Rev. A 55, 3797.ADSCrossRefGoogle Scholar
  19. 19.
    Gerton, J.M., Sackett, C.A., Frew, B.J., and Hulet, R.G. (1999) Dipolar relaxation collisions in magnetically trapped 7Li, Phys. Rev. A 59, 1514–1516.ADSCrossRefGoogle Scholar
  20. 20.
    Bradley, C.C., Sackett, C.A., and Hulet, R.G. (1997) Analysis of In Situ Images of Bose-Einstein Condensates of Lithium, Phys. Rev. A 55, 3951.ADSCrossRefGoogle Scholar
  21. 21.
    Sackett, C.A., Stoof, H.T.C, and Hulet, R.G. (1998) Growth and Collapse of a Bose Condensate with Attractive Interactions, Phys. Rev. Lett. 80, 2031–2034.ADSCrossRefGoogle Scholar
  22. 22.
    Sackett, C.A., Gerton, J.M., Welling, M., and Hulet, R.G. (1999) Measurements of Collective Collapse in a Bose-Einstein Condensate with Attractive Interactions, Phys. Rev. Lett. 82, 876.ADSCrossRefGoogle Scholar
  23. 23.
    Kagan, Y., Shlyapnikov, G.V., and Walraven, J.T.M. (1996) Bose-Einstein Condensation in Trapped Atomic Gases, Phys. Rev. Lett. 76, 2670–2673.ADSCrossRefGoogle Scholar
  24. 24.
    Shuryak, E.V. (1996) Bose Condensate made of Atoms with Attractive Interaction is Metastable, Phys. Rev. A 54, 3151.ADSCrossRefGoogle Scholar
  25. 25.
    Ueda, M. and Leggett, A.J. (1998) Macroscopic Quantum Tunneling of a Bose-Einstein Condensate with Attractive Interactions, Phys. Rev. Lett. 80, 1576.ADSCrossRefGoogle Scholar
  26. 26.
    Huepe, C., MŐtens, S., Dewel, G., Borckmans, P., and Brachat, M.E. (1999) Decay Rates in Attractive Bose-Einstein Condensates, Phys. Rev. Lett. 82, 1616–1619.ADSCrossRefGoogle Scholar
  27. 27.
    Singh, K.G., and Rokhsar, D.S. (1996) Collective Excitations of a Confined Bose Condensate, Phys. Rev. Lett. 77, 1667–1670.Google Scholar
  28. 28.
    Dodd, R.J., Edwards, M., Williams, C.J., Clark, C.W., Holland, M.J., Ruprecht, P.A., and Burnett, K. (1996) Role of attractive interactions on Bose-Einstein condensation, Phys. Rev. A 54, 661–664.ADSCrossRefGoogle Scholar
  29. 29.
    Kagan, Y., Muryshev, A.E., and Shlyapnikov, G.V. (1998) Collapse and Bose-Einstein Condensation in a Trapped Bose Gas with Negative Scattering Length, Phys. Rev. Lett. 81, 933–937.ADSCrossRefGoogle Scholar
  30. 30.
    Houbiers, M., and Stoof, H.T.C (1996) Stability of Bose condensed atomic 7Li, Phys. Rev. A 54, 505ADSCrossRefGoogle Scholar
  31. 31.
    Chandrasekhar, S. (1957) An Introduction to the Study of Stellar Structure, Dover, New York.zbMATHGoogle Scholar
  32. 32.
    Zhakharov, V.E. (1972) Collapse of Langmuir Waves, Sov. Phys. JETP 35, 908.ADSGoogle Scholar
  33. 33.
    Zhakharov, V.E., and Synakh, V.S. (1975) The nature of the self-focusing singularity, Sov. Phys. JETP 41, 465.ADSGoogle Scholar
  34. 34.
    Gammal, A., Frederico, T., Tomio, L., and Chomaz, P. (2000) Atomic Bose-Einstein condensation with three-body interactions and collective excitations, J. Phys. B 33, 4053–4067.ADSCrossRefGoogle Scholar
  35. 35.
    Miesner, H.-J., Stamper-Kurn, D.M., Andrews, M.R., Durfee, D.S., Inouye, S., and Ketterle, W. (1998) Bosonic Stimulation in the Formation of a Bose-Einstein Condensate, Science 279, 1005–1007.ADSCrossRefGoogle Scholar
  36. 36.
    Wynar, R., Freeland, R.S., Han, D.J., Ryu, C., and Heinzen, D.J. (2000) Molecules in a Bose-Einstein Condensate, Science 287, 1016–1019.ADSCrossRefGoogle Scholar
  37. 37.
    Napolitano, R., Weiner, J., Williams, C.J., and Julienne, P.S. (1994) Line Shapes of High Resolution Photoassociation Spectra of Optically Cooled Atoms, Phys. Rev. Lett. 73, 1352–1355.ADSCrossRefGoogle Scholar
  38. 38.
    Forrey, R.C., Kharchenko, V., Balakrishnan, N., and Dalgarno, A. (1999) Vibrational relaxation of trapped molecules, Phys. Rev. A 59, 2146–2152.ADSCrossRefGoogle Scholar
  39. 39.
    Gerton, J.M., Strekalov, D., Prodan, I., and Hulet, R.G. (2000) Direct observation of growth and collpase of a Bose-Einstein condensate with attractive interactions, Nature 408, 692–695.ADSCrossRefGoogle Scholar
  40. 40.
    Cornish, S.L., Claussen, N.R., Roberts, J.L., Cornell, E.A., and Wieman, C.E. (2000) Stable 85Rb Bose-Einstein condensates with widely tunable interactions, Phys. Rev. Lett. 85, 1795–1798.ADSCrossRefGoogle Scholar
  41. 41.
    DeMarco, B., and Jin, D.S. (1999) Onset of Fermi degeneracy in a trapped atomic gas, Science 285, 170CrossRefGoogle Scholar
  42. 42.
    Stoof, H.T.C., Houbiers, M., Sackett, C.A., and Hulet, R.G. (1996) Superfluidity of Spin-Polarized 6Li, Phys. Rev. Lett. 76, 10.ADSCrossRefGoogle Scholar
  43. 43.
    Houbiers, M., Ferwerda, R., Stoof, H.T.C., McAlexander, W.I., Sackett, C.A., and Hulet, R.G. (1997) The Superfluid State of Atomic 6Li in a Magnetic Trap, Phys. Rev. A 56, 4864–4878.ADSCrossRefGoogle Scholar
  44. 44.
    Leggett, A.J. (1980) Cooper Pairing in Spin-Polarized Fermi Systems, J. Phys. (Paris) C 7, 19.Google Scholar
  45. 45.
    Houbiers, M., Stoof, H.T.C., McAlexander, W.I., and Hulet, R.G. (1998) Elastic and inelastic collisions of 6Li atoms in magnetic and optical traps, Phys. Rev. A 57, R1497–1500.ADSCrossRefGoogle Scholar
  46. 46.
    Mewes, M.-O., Andrews, M.R., van Druten, N.J., Kurn, D.M., Durfee, D.S., and Ketterle, W. (1996) Bose-Einstein Condensation in a Tightly Confining dc Magnetic Trap, Phys. Rev. Lett. 77, 416–41ADSCrossRefGoogle Scholar
  47. 47.
    Larson, D.J., Bergquist, J.C., Bollinger, J.J., Itano, W.M., and Wineland, D.J. (1986) Sympathetic Cooling of Trapped Ions: A Laser-Cooled Two-Species Nonneutral Ion Plasma, Phys. Rev. Lett. 57, 70–73.ADSCrossRefGoogle Scholar
  48. 48.
    Myatt, C.J., Burt, E.A., Ghrist, R.W., Cornell, E.A., and Wieman, C.E. (1997) Production of Two Overlapping Bose-Einstein Condensates by Sympathetic Cooling, Phys. Rev. Lett. 78, 586–589.ADSCrossRefGoogle Scholar
  49. 49.
    Phillips, W.D., and Metcalf, H. (1982) Laser Deceleration of an Atomic Beam, Phys. Rev. Lett. 48, 596–599.ADSCrossRefGoogle Scholar
  50. 50.
    Zhang, W., Sackett, C.A., and Hulet, R.G. (1999) Optical detection of a Bardeen-Cooper-Schrieffer phase transition in a trapped gas of fermionic atoms, Phys. Rev. A 60, 504–507.ADSCrossRefGoogle Scholar
  51. 51.
    Ruostekoski, J. (1999) Optical response of a superfluid state in dilute atomic Fermi-Dirac gases, Phys. Rev. A 60, R1775-1778.Google Scholar
  52. 52.
    Torma, P., and Zoller, P. (2000) Laser Probing of Atomic Cooper Pairs, Phys. Rev. Lett. 85, 487–90.ADSCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2002

Authors and Affiliations

  1. 1.Department of Physics and AstronomyRice UniversityMS61 HoustonUSA

Personalised recommendations