## Nonequilibrium dynamical cluster theory    [PDF]

Naoto Tsuji, Peter Barmettler, Hideo Aoki, Philipp Werner
Effect of spatially nonlocal correlations on the nonequilibrium dynamics of interacting fermions is studied by constructing the nonequilibrium dynamical cluster theory, a cluster generalization of the nonequilibrium dynamical mean-field theory (DMFT). The formalism is applied to interaction quenches in the Hubbard model in one and two dimensions, where the result is compared with those in the single-site DMFT, the time-dependent density matrix renormalization group (DMRG), and lattice perturbation theory. Both in one and two dimensions the double occupancy quickly thermalizes while the momentum distribution relaxes only on much longer time scales. For a two-dimensional square lattice we observe a strongly momentum-dependent evolution of the momentum distribution around the Fermi energy, where the relaxation is much faster near the momenta $(0,\pi)$ and $(\pi,0)$ than near $(\pi/2,\pi/2)$. The result is then interpreted as reflecting the momentum-anisotropic quasiparticle lifetime of the marginal Fermi liquid.
View original: http://arxiv.org/abs/1307.5946