Heavy fermions in an optical lattice

TitleHeavy fermions in an optical lattice
Publication TypeJournal Article
Year of Publication2010
AuthorsFoss-Feig, M, Hermele, M, Gurarie, V, Rey, AMaria
JournalPhysical Review A
Date Published2010/11/22

We employ a mean-field theory to study ground-state properties and transport
of a two-dimensional gas of ultracold alklaline-earth metal atoms governed by
the Kondo Lattice Hamiltonian plus a parabolic confining potential. In a
homogenous system this mean-field theory is believed to give a qualitatively
correct description of heavy fermion metals and Kondo insulators: it reproduces
the Kondo-like scaling of the quasiparticle mass in the former, and the same
scaling of the excitation gap in the latter. In order to understand
ground-state properties in a trap we extend this mean-field theory via
local-density approximation. We find that the Kondo insulator gap manifests as
a shell structure in the trapped density profile. In addition, a strong
signature of the large Fermi surface expected for heavy fermion systems
survives the confinement, and could be probed in time-of-flight experiments.
From a full self-consistent diagonalization of the mean-field theory we are
able to study dynamics in the trap. We find that the mass enhancement of
quasiparticle excitations in the heavy Fermi liquid phase manifests as slowing
of the dipole oscillations that result from a sudden displacement of the trap

Short TitlePhys. Rev. A