Abstract
We study the transition to fermion pair superfluidity in a mixture of interacting bosonic and fermionic atoms. The fermion interaction induced by the bosons and the dynamical screening of the condensate phonons due to fermions are included using the nonperturbative Hamiltonian flow equations. We determine the bosonic spectrum near the transition towards phase separation and find that the superfluid transition temperature may be increased substantially due to phonon damping.
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B. DeMarco, D.S. Jin, Science 285, 1703 (1999); F. Schreck, L. Khaykovich, K.L. Corwin, G. Ferrari, T. Bourdel, J. Cubizolles, C. Salomon, Phys. Rev. Lett. 87, 080403 (2001); A.G. Truscott, K.E. Strecker, W.I. McAlexander, G.B. Partridge, R.G. Hulet, Science 291, 2570 (2001); G. Modugno, G. Ferrari, G. Roati, R.J. Brecha, A. Simoni, M. Inguscio, Science 294, 1320 (2001); G. Roati, F. Riboli, G. Modugno, M. Inguscio, Phys. Rev. Lett. 89, 150403 (2002)
M. Taglieber, A.C. Voigt, T. Aoki, T.W. Hänsch, K. Dieckmann, Phys. Rev. Lett. 100, 010401 (2008)
K. Mølmer, Phys. Rev. Lett. 80, 1804 (1998); L. Viverit, C.J. Pethick, H. Smith, Phys. Rev. A 61, 053605 (2000)
R. Roth, H. Feldmeier, Phys. Rev. A 65, 021603 (2002); S. Röthel, A. Pelster, Eur. Phys. J. B 59, 343 (2007); H. Shibata, N. Yokoshi, S. Kurihara, Phys. Rev. A 75, 053615 (2007)
G. Modugno, G. Roati, F. Riboli, F. Ferlaino, R.J. Brecha, M. Inguscio, Science 297, 2240 (2002)
C. Ospelkaus, S. Ospelkaus, K. Sengstock, K. Bongs, Phys. Rev. Lett. 96, 020401 (2006)
The collapse for attractive Bose-Fermi interactions is avoided by taking into account the possibility of pairing between bosons and fermions that is neglected in mean-field theory; see F.M. Marchetti, C. Mathy, M.M. Parish, D.A. Huse, Phys. Rev. B 78, 134517 (2008)
A. Simoni, F. Ferlaino, G. Roati, G. Modugno, M. Inguscio, Phys. Rev. Lett. 90, 163202 (2003); C.A. Stan, M.W. Zwierlein, C.H. Schunck, S.M.F. Raupach, W. Ketterle, Phys. Rev. Lett. 93, 143001 (2004); S. Inouye, J. Goldwin, M.L. Olsen, C. Ticknor, J.L. Bohn, D.S. Jin, Phys. Rev. Lett. 93, 183201 (2004); J. Zhang et al., in XIX International Conference on Atomic Physics, edited by L.G. Marcassa, V.S. Bagnato, K. Helmerson (AIP, Melville, NY, 2005), p. 228, arXiv:cond-mat/0410167; F. Ferlaino, C. D’Errico, G. Roati, M. Zaccanti, M. Inguscio, G. Modugno, A. Simoni, Phys. Rev. A 73, 40702 (2006); M. Zaccanti, C. D’Errico, F. Ferlaino, G. Roati, M. Inguscio, G. Modugno, Phys. Rev. A 74, 041605 (2006); S. Ospelkaus, C. Ospelkaus, L. Humbert, K. Sengstock, K. Bongs, Phys. Rev. Lett. 97, 120403 (2006)
H. Heiselberg, C.J. Pethick, H. Smith, L. Viverit, Phys. Rev. Lett. 85, 2418 (2000)
M.J. Bijlsma, B.A. Heringa, H.T.C. Stoof, Phys. Rev. A 61, 053601 (2000); F. Illuminati, A. Albus, Phys. Rev. Lett. 93, 090406 (2004)
D.V. Efremov, L. Viverit, Phys. Rev. B 65, 134519 (2002); K. Suzuki, T. Miyakawa, T. Suzuki, Phys. Rev. A 77, 043629 (2008)
R.M. Kalas, A.V. Balatsky, D. Mozyrsky, Phys. Rev. B 78, 184513 (2008)
H.P. Büchler, G. Blatter, Phys. Rev. Lett. 91, 130404 (2003); H.P. Büchler, G. Blatter, Phys. Rev. A 69, 063603 (2004)
M. Lewenstein, L. Santos, M.A. Baranov, H. Fehrmann, Phys. Rev. Lett. 92, 050401 (2004)
N. Ashcroft, N. Mermin, Solid state physics (Holt, Rinehart and Winston, New York, 1976)
H. Fröhlich, Proc. Roy. Soc. (London) A 215, 291 (1952)
Note that the effective potential becomes instantaneous only in the limit cs≫vF, while retardation effects are still negligible in the case cs≪vF relevant for electronic superconductivity because Tc/TF is exponentially small
W. Ketterle, M. Zwierlein, in Ultracold Fermi Gases, Proceedings of the International School of Physics “Enrico Fermi”, Varenna, edited by M. Inguscio, W. Ketterle, C. Salomon (IOS Press, Amsterdam, 2008), arXiv:0801.2500
I. Bloch, J. Dalibard, W. Zwerger, Rev. Mod. Phys. 80, 885 (2008)
S. Giorgini, L. Pitaevskii, S. Stringari, Rev. Mod. Phys. 80, 1215 (2008)
A.A. Abrikosov, L.P. Gorkov, I.E. Dzyaloshinski, Methods of quantum field theory in statistical physics (Prentice-Hall, Englewood Cliffs, NJ, 1963)
D.W. Wang, Phys. Rev. Lett. 96, 140404 (2006)
F. Wegner, Ann. Physik (Leipzig) 3, 77 (1994)
S. Kehrein, The Flow Equation Approach to Many-Particle Systems (Springer, Berlin, 2006)
P. Lenz, F. Wegner, Nucl. Phys. B 482, 693 (1996)
A. Mielke, Europhys. Lett. 40, 195 (1997)
C. Pethick, H. Smith, Bose-Einstein Condensation in Dilute Gases (Cambridge University Press, Cambridge, 2002)
G.D. Mahan, Many-Particle Physics (Plenum, New York, 2000)
T. Enss, W. Zwerger (in preparation)
L.P. Gorkov, T.K. Melik-Barkhudarov, Zh. Eksp. Teor. Fiz. 40 (1961)
Vertex corrections will become important at the transition towards phase separation but as in kalas2008ofp we assume that slightly away from the transition they are still small enough
J. Hertz, Phys. Rev. B 14, 1165 (1976)
M. Ragwitz, F. Wegner, Eur. Phys. J. B 8, 9 (1999)
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Enss, T., Zwerger, W. Superfluidity near phase separation in Bose-Fermi mixtures. Eur. Phys. J. B 68, 383–389 (2009). https://doi.org/10.1140/epjb/e2009-00005-y
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DOI: https://doi.org/10.1140/epjb/e2009-00005-y