BCS regime of the two-dimensional fermionic Hubbard model:ground-state phase diagram
Nikolay Prokofiev  1, *@  
1 : Physics Department, University of Massachusetts  (UMass)  -  Website
Amherst, MA 01003 -  United States
* : Corresponding author

A significant part of the T=0 phase diagram of the two-dimensional Fermi-Hubbard
model (U<5, n <0.8) is controlled by Fermi liquid physics with weak effective
BCS-type coupling. We access this regime in a controlled way using bold-line
diagrammatic Monte Carlo technique in combination with the semi-analytic treatment
of the weak instability in the Cooper channel. We obtain the corresponding T=0 phase diagram
in the (n,U) plane, describing the competition between the p- and d-wave superfluid states.
We also claim the values of the dimensionless BCS coupling constants---controlling the superfluid Tc---at
the phase boundaries, which prove to be very small up to U=4, n = 0.6.


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