Disorder-induced phase control in superfluid Fermi-Bose mixturesA. Niederberger1, J. Wehr1, 2, M. Lewenstein1, 3 and K. Sacha1, 4
1 ICFO-Institut de Ciències Fotòniques, Mediterranean Technology Park - 08860 Castelldefels (Barcelona), Spain, EU
2 Department of Mathematics, University of Arizona - Tucson, AZ 85721-0089, USA
3 ICREA-Instituciò Catalana de Ricerca i Estudis Avançats - 08010 Barcelona, Spain, EU
4 Marian Smoluchowski Institute of Physics and Mark Kac Complex Systems Research Centre, Jagiellonian University Reymonta 4, 30059 Kraków, Poland, EU
received 29 August 2008; accepted in final form 20 March 2009; published April 2009
published online 5 May 2009
We consider a mixture of a superfluid Fermi gas of ultracold atoms and a Bose-Einstein condensate of molecules possessing a continuous U(1) (relative phase) symmetry. We study the effects of a spatially random photo-associative–dissociative symmetry-breaking coupling of the systems. Such coupling allows one to control the relative phase between a superfluid order parameter of the Fermi system and the condensate wave function of molecules for temperatures below the Bardeen-Cooper-Schriefer critical temperature. The presented mechanism of phase control belongs to the general class of phenomena in which disorder interacts with continuous symmetry. Our results show the robustness and wide range of applicability of disorder-induced order and are valid for both disordered and regular couplings. Here, the effect is studied in the case of interacting fermionic and bosonic gases in the superfluid phase.
67.85.Pq - Mixtures of Bose and Fermi gases.
64.60.Cn - Order-disorder transformations.
03.75.Ss - Degenerate Fermi gases.
© EPLA 2009