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Ultracold atom superfluidity induced by the Feshbach resonance
Author(s) -
Domański T.
Publication year - 2005
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200460034
Subject(s) - feshbach resonance , superfluidity , atom (system on chip) , physics , resonance (particle physics) , ultracold atom , atomic physics , condensed matter physics , quantum mechanics , engineering , molecule , quantum , embedded system
We discuss the possible signatures of superfluidity induced by the Feshbach resonance in the ultracold gas of fermion atoms. Optically or magnetically trapped atoms such as 6 Li or 40 K are used in two hyperfine states where part of them is converted into the diatomic molecules. These fermion and boson entities get coupled in a presence of the external magnetic field. Eventually, at critical T c , they simultaneously undergo transition to the superfluid state. Approaching this transition from above there appear various signatures manifesting a gradually emerging order parameter, but yet the long range coherence is not established due to the strong quantum fluctuations. Fermion atoms are characterized by the gapped excitation spectrum ( pseudogap ) up to temperature T p (larger than T c ) while boson molecules exhibit collective features such as first sound showing up above a certain critical momentum q . crit ( T ) Upon lowering temperature to T c this critical value shifts to zero and hence there appears the Goldstone mode signaling the symmetry broken superfluid state. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)