0000000000283067

AUTHOR

Richard T. Scalettar

showing 3 related works from this author

Universal probes for antiferromagnetic correlations and entropy in cold fermions on optical lattices

2012

We determine antiferromagnetic (AF) signatures in the half-filled Hubbard model at strong coupling on a cubic lattice and in lower dimensions. Upon cooling, the transition from the charge-excitation regime to the AF Heisenberg regime is signaled by a universal minimum of the double occupancy at entropy s=S/(N k_B)=s*=ln(2) per particle and a linear increase of the next-nearest neighbor (NNN) spin correlation function for s<s*. This crossover, driven by a gain in kinetic exchange energy, appears as the essential AF physics relevant for current cold-atom experiments. The onset of long-range AF order (at low s on cubic lattices) is hardly visible in nearest-neighbor spin correlations versus s,…

PhysicsStrongly Correlated Electrons (cond-mat.str-el)Hubbard modelCondensed matter physicsExchange interactionFOS: Physical sciencesFermionApproxKinetic energyAtomic and Molecular Physics and OpticsCondensed Matter - Strongly Correlated ElectronsQuantum Gases (cond-mat.quant-gas)Lattice (order)AntiferromagnetismCondensed Matter::Strongly Correlated ElectronsCondensed Matter - Quantum GasesEntropy (order and disorder)
researchProduct

Realistic investigations of correlated electron systems with LDA + DMFT

2006

Conventional band structure calculations in the local density approximation (LDA) [1–3] are highly successful for many materials, but miss important aspects of the physics and energetics of strongly correlated electron systems, such as transition metal oxides and f-electron systems displaying, e.g., Mott insulating and heavy quasiparticle behavior. In this respect, the LDA + DMFT approach which merges LDA with a modern many-body approach, the dynamical mean-field theory (DMFT), has proved to be a breakthrough for the realistic modeling of correlated materials. Depending on the strength of the electronic correlation, a LDA + DMFT calculation yields the weakly correlated LDA results, a strong…

Condensed Matter::Quantum GasesCondensed matter physicsHubbard modelElectronic correlationChemistryMott insulatorQuantum Monte CarloCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsQuasiparticleCondensed Matter::Strongly Correlated ElectronsStrongly correlated materialddc:530Metal–insulator transitionLocal-density approximation
researchProduct

Discriminating antiferromagnetic signatures in systems of ultracold fermions by tunable geometric frustration

2013

Recently, it has become possible to tune optical lattices continuously between square and triangular geometries. We compute thermodynamics and spin correlations in the corresponding Hubbard model using a determinant quantum Monte Carlo technique and show that the frustration effects induced by the variable hopping terms can be clearly separated from concomitant bandwidth changes by a proper rescaling of the interaction. An enhancement of the double occupancy by geometric frustration signals the destruction of nontrivial antiferromagnetic correlations at weak coupling and entropy $s\ensuremath{\lesssim}\mathrm{ln}(2)$ (and restores Pomeranchuk cooling at strong frustration), paving the way t…

PhysicsCondensed matter physicsHubbard modelQuantum Monte Carlomedia_common.quotation_subjectFrustrationFermionCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsQuantum mechanicsAntiferromagnetismCondensed Matter::Strongly Correlated ElectronsA determinantmedia_commonPhysical Review B
researchProduct