Nonthermal Antiferromagnetic Order and Nonequilibrium Criticality in the Hubbard Model
Abstract
We study dynamical phase transitions from antiferromagnetic to paramagnetic states driven by an interaction quench in the fermionic Hubbard model using the nonequilibrium dynamical meanfield theory. We identify two dynamical transition points where the relaxation behavior qualitatively changes: one corresponds to the thermal phase transition at which the order parameter decays critically slowly in a power law ∝t^{1/2}, and the other is connected to the existence of nonthermal antiferromagnetic order in systems with effective temperature above the thermal critical temperature. The frequency of the amplitude mode extrapolates to zero as one approaches the nonthermal (quasi)critical point, and thermalization is significantly delayed by the trapping in the nonthermal state. A slow relaxation of the nonthermal order is followed by a faster thermalization process.
 Publication:

Physical Review Letters
 Pub Date:
 March 2013
 DOI:
 10.1103/PhysRevLett.110.136404
 arXiv:
 arXiv:1210.0133
 Bibcode:
 2013PhRvL.110m6404T
 Keywords:

 71.10.Fd;
 64.60.Ht;
 Lattice fermion models;
 Dynamic critical phenomena;
 Condensed Matter  Strongly Correlated Electrons;
 Condensed Matter  Statistical Mechanics
 EPrint:
 Phys. Rev. Lett. 110, 136404 (2013)