Auxiliary-field quantum Monte Carlo method for strongly paired fermions

被引:124
作者
Carlson, J. [1 ]
Gandolfi, Stefano [1 ]
Schmidt, Kevin E. [2 ]
Zhang, Shiwei [3 ]
机构
[1] Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA
[2] Arizona State Univ, Dept Phys, Tempe, AZ 85287 USA
[3] Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA
来源
PHYSICAL REVIEW A | 2011年 / 84卷 / 06期
基金
美国国家科学基金会;
关键词
D O I
10.1103/PhysRevA.84.061602
中图分类号
O43 [光学];
学科分类号
070207 ; 0803 ;
摘要
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 27(3) sites, obtaining an accurate result for the universal parameter xi. 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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页数:5
相关论文
共 31 条
[1]   Auxiliary-field quantum Monte Carlo calculations of molecular systems with a Gaussian basis [J].
Al-Saidi, W. A. ;
Zhang, Shiwei ;
Krakauer, Henry .
JOURNAL OF CHEMICAL PHYSICS, 2006, 124 (22)
[2]   QUANTUM CHEMISTRY BY RANDOM-WALK - H2P,H+3D3H1A'1,H-23-SIGMA+U,H-41-SIGMA+G,BE1S [J].
ANDERSON, JB .
JOURNAL OF CHEMICAL PHYSICS, 1976, 65 (10) :4121-4127
[3]   Equation of state of a Fermi gas in the BEC-BCS crossover: A quantum Monte Carlo study [J].
Astrakharchik, GE ;
Boronat, J ;
Casulleras, J ;
Giorgini, S .
PHYSICAL REVIEW LETTERS, 2004, 93 (20) :200404-1
[4]   THEORY OF SUPERCONDUCTIVITY [J].
BARDEEN, J ;
COOPER, LN ;
SCHRIEFFER, JR .
PHYSICAL REVIEW, 1957, 108 (05) :1175-1204
[5]   Collective excitations of a degenerate gas at the BEC-BCS crossover [J].
Bartenstein, M ;
Altmeyer, A ;
Riedl, S ;
Jochim, S ;
Chin, C ;
Denschlag, JH ;
Grimm, R .
PHYSICAL REVIEW LETTERS, 2004, 92 (20) :203201-1
[6]   Precision benchmark calculations for four particles at unitarity [J].
Bour, Shahin ;
Li, Xin ;
Lee, Dean ;
Meissner, Ulf-G. ;
Mitas, Lubos .
PHYSICAL REVIEW A, 2011, 83 (06)
[7]   Spin 1/2 fermions in the unitary regime: A superfluid of a new type [J].
Bulgac, A ;
Drut, JE ;
Magierski, P .
PHYSICAL REVIEW LETTERS, 2006, 96 (09)
[8]   Asymmetric two-component fermion systems in strong coupling [J].
Carlson, J ;
Reddy, S .
PHYSICAL REVIEW LETTERS, 2005, 95 (06)
[9]   Superfluid Fermi gases with large scattering length [J].
Carlson, J ;
Chang, SY ;
Pandharipande, VR ;
Schmidt, KE .
PHYSICAL REVIEW LETTERS, 2003, 91 (05) :504011-504014
[10]  
Castin Y., 2012, LECT NOTES PHYS, V836