2000/08/31 by Muoi N. Tran, Muoi Tran, M. V. N. Murthy +1 · 1 citation
Mathematics · Physics and Astronomy · #Canonical ensemble #Cold Atom Physics and Bose-Einstein Condensates #Excitation #Fermi Gamma-ray Space Telescope #Fermion #Grand canonical ensemble #Ground state #Harmonic #Mathematics #Microcanonical ensemble #Physics #Quantum electrodynamics #Quantum many-body systems #Quantum mechanics #Quantum, superfluid, helium dynamics #State (computer science) #Statistical physics #Statistics #Trap (plumbing) #cond-mat.stat-mech
paper · pdf · doi:10.1103/physreve.63.031105
20 pages (including 1 appendix), 3 postscript figures. An error was found in one section of the paper. The corrected version is updated on Sep/05/2000
arxiv created 2000/09/05 · openalex publication_date 2001/02/21 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We consider a small and fixed number of fermions in a trap. The ground state of the system is defined at T=0. For a given excitation energy, there are several ways of exciting the particles from this ground state. We formulate a method for calculating the number fluctuation in the ground state using microcanonical counting, and implement it for noninteracting fermions in harmonic confinement. This exact calculation for fluctuation, when compared with canonical or grand canonical ensemble averaging, gives considerably different results. This difference is expected to persist at low excitation even when the fermion number in the trap is large. For comparison, the well-known bosonic results are also given.