Thermal versus Quantum Fluctuations of Optical Lattice Fermions

Abstract

We show that, for fermionic atoms in a one-dimensional optical lattice, the fraction of atoms in doubly occupied sites is a highly non-monotonic function of temperature. We demonstrate that this property persists even in the presence of realistic harmonic confinement, and that it leads to a suppression of entropy at intermediate temperatures that offers a route to adiabatic cooling. Our interpretation of the suppression is that such intermediate temperatures are simultaneously too high for quantum coherence and too low for significant thermal excitation of double occupancy thus offering a clear indicator of the onset of quantum fluctuations.

typos corrected; figures improved; some additional discussions

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Cited by in corpus (5)

• The Hubbard Dimer: A density functional case study of a many-body problem
• Interacting fermions in 1D disordered lattices: Exploring localization and transport properties with lattice density-functional theories
• Competition of spin and charge excitations in the Hubbard model
• Density-functional theory approach to the thermodynamics of the harmonically confined one-dimensional Hubbard model
• Quantum critical behavior and thermodynamics of the repulsive one-dimensional Hubbard model in a magnetic field