Dynamical quantum phase transitions in dilute Bose gases
Date : December 2, 2009 16:00 ~
Speaker : Uwe R. Fischer(SNU, Korea)
Professor :
Location : 56동106호
We study dynamical quantum phase transitions in dilute Bose gases, for which the nonequilibrium nature of the transition becomes physically manifest in allowing for the unprecedented possibility to study many-body correlations in real time.
We explicitly investigate two such phase transitions.
The first example is bosons in an optical lattice undergoing a very rapid increase of the lattice depth, thus bringing the system quasi-instantaneously from the delocalized phase-coherent superfluid phase to the number-squeezed and localized Mott phase. The second is a
paramagnetic-ferromagnetic transition in a spinor Bose gas, in the course of which topological defects -- so-called spin vortices -- are created by a quantum version of the Kibble-Zurek scenario of second-order phase transitions. It is shown that, generically, the variance of the defect number scales with the surface area of the volume containing them.
We explicitly investigate two such phase transitions.
The first example is bosons in an optical lattice undergoing a very rapid increase of the lattice depth, thus bringing the system quasi-instantaneously from the delocalized phase-coherent superfluid phase to the number-squeezed and localized Mott phase. The second is a
paramagnetic-ferromagnetic transition in a spinor Bose gas, in the course of which topological defects -- so-called spin vortices -- are created by a quantum version of the Kibble-Zurek scenario of second-order phase transitions. It is shown that, generically, the variance of the defect number scales with the surface area of the volume containing them.