The Fermionic Density-functional at Feshbach Resonance
arXiv:0704.0769 · doi:10.1103/PhysRevA.75.052509
Abstract
We consider a dilute gas of neutral unpolarized fermionic atoms at zero temperature.The atoms interact via a short range (tunable) attractive interaction. We demonstrate analytically a curious property of the gas at unitarity. Namely, the correlation energy of the gas, evaluated by second order perturbation theory, has the same density dependence as the first order exchange energy, and the two almost exactly cancel each other at Feshbach resonance irrespective of the shape of the potential, provided . Here is the range of the two-body potential, and is defined through the number density . The implications of this result for universality is discussed.
Five pages, one table. accepted for publication in PRA
References in corpus (16)
- Observation of resonance condensation of fermionic atom pairs
- Vortices and Superfluidity in a Strongly Interacting Fermi Gas
- Pairing and Phase Separation in a Polarized Fermi Gas
- Observation of Bose-Einstein Condensation of Molecules
- Experimental Study of the BEC-BCS Crossover Region in Lithium 6
- Creation of ultracold molecules from a Fermi gas of atoms
- Crossover from a molecular Bose-Einstein condensate to a degenerate Fermi gas
- Superfluid Fermi Gases with Large Scattering Length
- Universal Thermodynamics of Degenerate Quantum Gases in the Unitarity Limit
- Fermi systems with long scattering lengths
- Spin 1/2 Fermions in the Unitary Regime: A Superfluid of a New Type
- Critical Temperature and Thermodynamics of Attractive Fermions at Unitarity
- Quantitative comparison between theoretical predictions and experimental results for the BCS-BEC crossover
- Density-functional theory for fermions in the unitary regime
- A local density functional for the short-range part of the electron-electron interaction
- Density functional theory for fermions close to the unitary regime