Ground state fluctuations in finite Fermi and Bose systems

Abstract

We consider a small and fixed number of fermions (bosons) 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 small systems of noninteracting fermions as well as bosons in harmonic confinement. This exact calculation for fluctuation, when compared with canonical ensemble averaging, gives considerably different results, specially for fermions. This difference is expected to persist at low excitation even when the fermion number in the trap is large.

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

References in corpus (4)

• Evaporative Cooling of a Two-Component Degenerate Fermi Gas
• Hydrodynamic Excitations of Trapped Fermi Gases
• The saddle-point method for condensed Bose gases
• Quantum Statistical Model of Nuclear Multifragmentation in the Canonical Ensemble Method

Cited by in corpus (9)

• Nonequilibrium Green's functions approach to strongly correlated few-electron quantum dots
• Number Fluctuation in an interacting trapped gas in one and two dimensions
• On the Microcanonical Entropy of a Black Hole
• Thermodynamics of low-dimensional trapped Fermi gases
• Exact ground state number fluctuations of trapped ideal and interacting fermions
• Condensation in ideal Fermi gases
• Number Fluctuation and the Fundamental Theorem of Arithmetic
• A finite temperature study of ideal quantum gases in the presence of one dimensional quasi-periodic potential
• Inclusive spectra and Bose-Einstein correlations in small thermal quantum systems