Volume 110, Number 5, June 2015
|Number of page(s)||6|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||16 June 2015|
Emergent BCS regime of the two-dimensional fermionic Hubbard model: Ground-state phase diagram
1 Hefei National Laboratory for Physical Sciences at Microscale, Department of Modern Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China Hefei, Anhui 230026, China
2 Department of Physics, University of Massachusetts - Amherst, MA 01003, USA
3 Department of Physics, King's College London - Strand, London WC2R 2LS, UK
4 Centre de Physique Théorique, Ecole Polytechnique, CNRS - 91128 Palaiseau Cedex, France
5 Russian Research Center “Kurchatov Institute” - 123182 Moscow, Russia
Received: 8 April 2015
Accepted: 29 May 2015
For over half a century, the Hubbard model has played a paradigmatic role in attempts to understand quantum phenomena exhibited by correlated electrons in solids. Despite a substantial effort and the apparent simplicity of the model, its behavior in many important regimes has remained unknown. Here we study superfluidity in the two-dimensional Hubbard model with controlled error bars up to the coupling strength U = 4 and filling factor . We show, by means of unbiased diagrammatic Monte Carlo simulations, that in this regime the superfluid transition is governed by Fermi liquid physics with an emergent weak BCS-type coupling driving the instability. The corresponding ground-state phase diagram in the plane describes the competition between the superfluid states of p- and d-wave symmetry. We also report dimensionless coupling constants in this effective BCS regime.
PACS: 71.10.Fd – Lattice fermion models (Hubbard model, etc.) / 02.70.Ss – Quantum Monte Carlo methods / 74.20.Fg – BCS theory and its development
© EPLA, 2015
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