G Li

Publications (1)7.37 Total impact

• Source

  Available from: Mikhail I. Katsnelson

  Article: Efficient perturbation theory for quantum lattice models.

  H Hafermann, G Li, A N Rubtsov, M I Katsnelson, A I Lichtenstein, H Monien
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  ABSTRACT: We present a novel approach to long-range correlations beyond dynamical mean-field theory, through a ladder approximation to dual fermions. The new technique is applied to the two-dimensional Hubbard model. We demonstrate that the transformed perturbation series for the nonlocal dual fermions has superior convergence properties over standard diagrammatic techniques. The critical Néel temperature of the mean-field solution is suppressed in the ladder approximation, in accordance with quantum Monte Carlo results. An illustration of how the approach captures and allows us to distinguish short- and long-range correlations is given.
  Physical Review Letters 06/2009; 102(20):206401. · 7.37 Impact Factor