6533b82ffe1ef96bd129593f
RESEARCH PRODUCT
Dynamical mean-field theory versus second-order perturbation theory for the trapped two-dimensional Hubbard antiferromagnet
Tobias GottwaldPeter Van DongenEberhard JakobiAndreas Daniel Pfistersubject
Condensed Matter::Quantum GasesQuantum phase transitionPhysicsPhase transitionCondensed matter physicsOrder (ring theory)Condensed Matter PhysicsElectronic Optical and Magnetic MaterialsPhase (matter)Quantum mechanicsAntiferromagnetismCondensed Matter::Strongly Correlated ElectronsPerturbation theoryQuantumQuantum fluctuationdescription
In recent literature on trapped ultracold atomic gases, calculations for two-dimensional (2D) systems are often done within the dynamical mean-field theory (DMFT) approximation. In this paper, we compare DMFT to a fully 2D, self-consistent second-order perturbation theory for weak interactions in a repulsive Fermi-Hubbard model. We investigate the role of quantum and of spatial fluctuations when the system is in the antiferromagnetic phase, and find that, while quantum fluctuations decrease drastically the order parameter and critical temperatures, spatial fluctuations only play a noticeable role when the system undergoes a phase transition, or at phase boundaries in the trap. We conclude from this that DMFT is a good approximation for the antiferromagnetic Fermi-Hubbard model for experimentally relevant system sizes.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2011-10-19 | Physical Review B |