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Article Dans Une Revue Physical Review B: Condensed Matter and Materials Physics (1998-2015) Année : 2008

Sign change of the extended s-wave pairing vertex in the dynamic Hubbard model : a quantum Monte Carlo study

Résumé

The “dynamic” Hubbard Hamiltonian describes interacting fermions on a lattice whose on-site repulsion is modulated by a coupling to a fluctuating bosonic field. We investigate one such model, introduced by Hirsch, using the determinant quantum Monte Carlo method. Our key result is that the extended s-wave pairing vertex, repulsive in the usual static Hubbard model, becomes attractive as the coupling to the fluctuating Bose field increases. The sign problem prevents us from exploring a low enough temperature to see if a superconducting transition occurs. We also observe a stabilization of antiferromagnetic correlations and the Mott gap near half-filling, and a near linear behavior of the energy as a function of particle density which indicates a tendency toward phase separation.

Dates et versions

hal-00257883 , version 1 (20-02-2008)

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Citer

Karem Bouadim, Matthew Enjalran, Frederic Hebert, G. G. Batrouni, R. T. Scalettar. Sign change of the extended s-wave pairing vertex in the dynamic Hubbard model : a quantum Monte Carlo study. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2008, 77 (1), pp.014516. ⟨10.1103/PhysRevB.77.014516⟩. ⟨hal-00257883⟩
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