2009/03/31 by N. T. Zinner, Klaus Mølmer, K. Mølmer +3 · 1 citation
Mathematics · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Convergence (economics) #Crossover #Diffusion Monte Carlo #Fermion #Hubbard model #Markov chain Monte Carlo #Mathematics #Mean field theory #Monte Carlo method #Monte Carlo molecular modeling #Physics #Physics of Superconductivity and Magnetism #Quantum Chromodynamics and Particle Interactions #Quantum Monte Carlo #Quantum mechanics #Renormalization group #Statistical physics #Superconductivity #Unitarity #cond-mat.quant-gas #cond-mat.supr-con #nucl-th
paper · pdf · doi:10.1103/physreva.80.013613
published as Phys. Rev. A 80, 013613 (2009) · 6 pages, 5 figures, Revtex4, final version
arxiv created 2009/07/23 · openalex publication_date 2009/07/23 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study a trapped system of fermions with a zero-range two-body interaction using the shell-model Monte Carlo method, providing ab initio results for the low particle number limit where mean-field theory is not applicable. We present results for the N-body energies as function of interaction strength, particle number, and temperature. The subtle question of renormalization in a finite model space is addressed and the convergence of our method and its applicability across the BCS-BEC crossover is discussed. Our findings indicate that very good quantitative results can be obtained on the BCS side, whereas at unitarity and in the BEC regime the convergence is less clear. Comparison to N=2 analytics at zero and finite temperature, and to other calculations in the literature for N>2 show very good agreement.