TY - JOUR
T1 - Auxiliary-field quantum Monte Carlo method for strongly paired fermions
AU - Carlson, J.
AU - Gandolfi, Stefano
AU - Schmidt, Kevin
AU - Zhang, Shiwei
PY - 2011/12/7
Y1 - 2011/12/7
N2 - We solve the zero-temperature unitary Fermi gas problem by incorporating a BCS importance function into the auxiliary-field quantum Monte Carlo method. We demonstrate that this method does not suffer from a sign problem and that it increases the efficiency of standard techniques by many orders of magnitude for strongly paired fermions. We calculate the ground-state energies exactly for unpolarized systems with up to 66 particles on lattices of up to 273 sites, obtaining an accurate result for the universal parameter ξ. We also obtain results for interactions with different effective ranges and find that the energy is consistent with a universal linear dependence on the product of the Fermi momentum and the effective range. This method will have many applications in superfluid cold atom systems and in both electronic and nuclear structures where pairing is important.
AB - We solve the zero-temperature unitary Fermi gas problem by incorporating a BCS importance function into the auxiliary-field quantum Monte Carlo method. We demonstrate that this method does not suffer from a sign problem and that it increases the efficiency of standard techniques by many orders of magnitude for strongly paired fermions. We calculate the ground-state energies exactly for unpolarized systems with up to 66 particles on lattices of up to 273 sites, obtaining an accurate result for the universal parameter ξ. We also obtain results for interactions with different effective ranges and find that the energy is consistent with a universal linear dependence on the product of the Fermi momentum and the effective range. This method will have many applications in superfluid cold atom systems and in both electronic and nuclear structures where pairing is important.
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U2 - 10.1103/PhysRevA.84.061602
DO - 10.1103/PhysRevA.84.061602
M3 - Article
AN - SCOPUS:83655164943
SN - 1050-2947
VL - 84
JO - Physical Review A - Atomic, Molecular, and Optical Physics
JF - Physical Review A - Atomic, Molecular, and Optical Physics
IS - 6
M1 - 061602
ER -