JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR: "Relaxation dynamics of isolated many-body systems"

[Statistical Physics Group]

JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR

Tuesday, 17 February 2009   -    12:30 hrs



Lecture Room D

SISSA Main Building



Marcus KOLLAR

(Universität Augsburg)

" Relaxation dynamics of

isolated many-body systems "



Abstract



If an isolated quantum-mechanical many-body system is suddenly forced  
out of thermal equilibrium, does it relax to a new steady state or  
does it keep oscillating?  How does the final state depend on the  
initial state?  Recently it has become possible to investigate such  
fundamental questions in experiments with ultracold atomic gases.  
Here we study two models of interacting fermions, the Falicov-Kimball  
model in dynamical mean-field theory [1] and a Hubbard chain with  
long-range hopping [2]. We obtain the exact real-time dynamics after  
a sudden change of the Hubbard interaction, starting from a metallic  
or a Mott-insulating initial state. We observe relaxation to a new  
steady state, showing that the presence of the Mott gap does not  
inhibit relaxation. The steady-state properties are described by  
generalized Gibbs ensembles which take all constants of motion into  
account. We discuss under which conditions such ensembles provide the  
correct statistical description of integrable systems [2].



[1] M. Eckstein and M. Kollar, Phys. Rev. Lett. 100, 120404 (2008).

[2] M. Kollar and M. Eckstein, Phys. Rev. A 78, 013626 (2008).