dorsal/arxiv
View SchemaUnitary Fermi Gas in a Harmonic Trap
| Authors | S. Y. Chang, G. F. Bertsch |
|---|---|
| Categories | |
| ArXiv ID | physics/0703190 |
| URL | https://arxiv.org/abs/physics/0703190 |
| DOI | 10.1103/PhysRevA.76.021603 |
| Journal | Phys.Rev.A76:021603,2007 |
Abstract
We present an {\it ab initio} calculation of small numbers of trapped, strongly interacting fermions using the Green's Function Monte Carlo method (GFMC). The ground state energy, density profile and pairing gap are calculated for particle numbers $N = 2 \sim 22$ using the parameter-free "unitary" interaction. Trial wave functions are taken of the form of correlated pairs in a harmonic oscillator basis. We find that the lowest energies are obtained with a minimum explicit pair correlation beyond that needed to exploit the degeneracy of oscillator states. We find that energies can be well fitted by the expression $a_{TF} E_{TF} + \Delta {\rm mod}(N,2)$ where $E_{TF}$ is the Thomas-Fermi energy of a noninteracting gas in the trap and $\Delta$ is a pairing gap. There is no evidence of a shell correction energy in the systematics, but the density distributions show pronounced shell effects. We find the value $\Delta= 0.7\pm 0.2\omega$ for the pairing gap. This is smaller than the value found for the uniform gas at a density corresponding to the central density of the trapped gas.
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"abstract": "We present an {\\it ab initio} calculation of small numbers of trapped,\nstrongly interacting fermions using the Green\u0027s Function Monte Carlo method\n(GFMC). The ground state energy, density profile and pairing gap are calculated\nfor particle numbers $N = 2 \\sim 22$ using the parameter-free \"unitary\"\ninteraction. Trial wave functions are taken of the form of correlated pairs in\na harmonic oscillator basis. We find that the lowest energies are obtained with\na minimum explicit pair correlation beyond that needed to exploit the\ndegeneracy of oscillator states. We find that energies can be well fitted by\nthe expression $a_{TF} E_{TF} + \\Delta {\\rm mod}(N,2)$ where $E_{TF}$ is the\nThomas-Fermi energy of a noninteracting gas in the trap and $\\Delta$ is a\npairing gap. There is no evidence of a shell correction energy in the\nsystematics, but the density distributions show pronounced shell effects. We\nfind the value $\\Delta= 0.7\\pm 0.2\\omega$ for the pairing gap. This is smaller\nthan the value found for the uniform gas at a density corresponding to the\ncentral density of the trapped gas.",
"arxiv_id": "physics/0703190",
"authors": [
"S. Y. Chang",
"G. F. Bertsch"
],
"categories": [
"physics.atom-ph"
],
"doi": "10.1103/PhysRevA.76.021603",
"journal_ref": "Phys.Rev.A76:021603,2007",
"title": "Unitary Fermi Gas in a Harmonic Trap",
"url": "https://arxiv.org/abs/physics/0703190"
},
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