Sign-free stochastic mean-field approach to strongly correlated phases of ultracold fermions

Abstract

We propose a new projector quantum Monte-Carlo method to investigate the ground state of ultracold fermionic atoms modeled by a lattice Hamiltonian with on-site interaction. The many-body state is reconstructed from Slater determinants that randomly evolve in imaginary-time according to a stochastic mean-field motion. The dynamics prohibits the crossing of the exact nodal surface and no sign problem occurs in the Monte-Carlo estimate of observables. The method is applied to calculate ground-state energies and correlation functions of the repulsive two-dimensional Hubbard model. Numerical results for the unitary Fermi gas validate simulations with nodal constraints.

Accepted for publication in New Journal of Physics

References in corpus (7)

• Computational complexity and fundamental limitations to fermionic quantum Monte Carlo simulations
• Vortices and Superfluidity in a Strongly Interacting Fermi Gas
• Crossover from a molecular Bose-Einstein condensate to a degenerate Fermi gas
• Critical Temperature and Thermodynamics of Attractive Fermions at Unitarity
• Implementation of Spin Hamiltonians in Optical Lattices
• Gapless quantum spin liquid, stripe and antiferromagnetic phases in frustrated Hubbard models in two dimensions
• Quantum-number projection in the path-integral renormalization group method

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• Three fermions in a box at the unitary limit: universality in a lattice model
• Precision benchmark calculations for four particles at unitarity
• The self-energy of an impurity in an ideal Fermi gas to second order in the interaction strength
• Phaseless quantum Monte-Carlo approach to strongly correlated superconductors with stochastic Hartree-Fock-Bogoliubov wavefunctions
• An Effective Series Expansion to the Equation of State of Unitary Fermi Gases