Non-equilibrium dynamics of the pairing correlations in unitary Fermi gases
* SPEAKERS
Name
Affiliation
E-mail
Dr. Sukjin Yoon
* HOST(Applicant)
Name
Affiliation
E-mail
-
* DATE / TIME
2010-10-12, 10:00 am
* PLACE
Conference room 503, APCTP Headquarters, POSTECH, Pohang, Korea
* ABSTRACT
The unprecedented control over ultracold atomic gases has made it possible to use these system as test beds of broad areas of physics, from condensed matter physics to QCD and nuclear systems. Relatively large characteristic time scale of the dilute Fermi gas due to the small Fermi energy scale of the system make it easier that one can change the system parameter (like scattering length) or external potential non-adiabatically as well as do time-resolved measurements on the intrinsic microscopic time scales. This has motivated recent efforts to investigate the time evolution of non-equilibrium state of condensate created in the non-adiabatic regime.
In this talk, we investigate non-equilibrium dynamics of the pairing correlations in unitary Fermi gases. For studying the dynamical properties of Fermi gases at unitarity, we adopt the Time-Dependent Superfluid Local Density Approximation (TD-SLDA) . We consider two cases : (1) In homogeneous system a Fermi gas, excited by a quick time variation of the scattering length, has a rich spectrum of large amplitude modes of the pairing field alone and there are very slow modes with oscillation frequencies well below the pairing gap, which makes their damping through quasiparticle excitations quite ineffective. (2) In atomic traps these modes couple naturally with the density oscillations and the corresponding oscillations of the atomic cloud are an example of a new type of collective mode in superfluid Fermi systems. They have frequencies different from the compressional collective hydrodynamic oscillations, have a non-spherical momentum distribution. Finally, we discuss other possible applications of TD-SLDA.
