Finite-range effects in dilute Fermi gases at unitarity

Abstract

We develop a theoretical method going beyond the contact-interaction approximation frequently used in mean-field theories of many-fermion systems, based on the low-energy T-matrix of the pair potential to rigorously define the effective radius of the interaction. One of the main consequences of our approach is the possibility to investigate finite-density effects, which are outside the range of validity of approximations based on delta-like potentials. We apply our method to the calculation of density dependent properties of an ultracold gas of 6Li atoms at unitarity, whose two-body interaction potential is calculated using ab initio quantum chemistry methods. We find that density effects will be significant in ultracold gases with densities one order of magnitude higher than those attained in current experiments.

7 pages, 3 figures. v2: Corrected typos in the main text and in the references

References in corpus (13)

• Theory of ultracold Fermi gases
• Color superconductivity in dense quark matter
• Vortices and Superfluidity in a Strongly Interacting Fermi Gas
• Strongly paired fermions: Cold atoms and neutron matter
• Determination of the Superfluid Gap in Atomic Fermi Gases by Quasiparticle Spectroscopy
• Quantum Monte Carlo Simulations of the BCS-BEC Crossover at Finite Temperature
• Polarization Measurements and the Pairing Gap in the Universal Regime
• Generation and Dynamics of Quantized Vortices in a Unitary Fermi Superfluid
• Mixed-Spin Pairing Condensates in Heavy Nuclei
• Magnetic field control of elastic scattering in a cold gas of fermionic lithium atoms
• Broad versus narrow Fano-Feshbach resonances in the BCS-BEC crossover with trapped Fermi atom
• Multi-channel scattering and Feshbach resonances: Effective theory, phenomenology, and many-body effects
• Bogoliubov-de Gennes study of trapped spin-imbalanced unitary Fermi gases

Cited by in corpus (6)

• Effective-Range Dependence of Resonantly Interacting Fermions
• Collective excitations of a trapped Fermi gas at finite temperature
• Spin relaxation in ultracold spin-orbit coupled ${}^{40}$K gas
• Magnetic phases and phase diagram of spin-1 condensate with quadrupole degrees of freedom
• SU(3) symmetry in theory of a weakly interacting gas of spin-1 atoms with Bose-Einstein condensate
• Broken-axisymmetry state and magnetic state diagram of spin-1 condensate through the prism of quadrupole degrees of freedom