title: Energy fluctuations of a finite free-electron Fermi gas.
abstract: We discuss the energy distribution of free-electron Fermi-gas, a problem with a textbook solution of Gaussian energy fluctuations in the limit of a large system. We find that for a small system, characterized solely by its heat capacity C, the distribution can be solved analytically, and it is both skewed and it vanishes at low energies, exhibiting a sharp drop to zero at the energy corresponding to the filled Fermi sea. The results are relevant from the experimental point of view, since the predicted non-Gaussian effects become pronounced when C/k_{B}≲10^{3} (k_{B} is the Boltzmann constant), a regime that can be easily achieved for instance in mesoscopic metallic conductors at sub-kelvin temperatures.
authors.affiliation: Low Temperature Laboratory, Department of Applied Physics, Aalto University School of Science, P.O. Box 13500, 00076 Aalto, Finland.
authors.forename: Jukka P
authors.initials: JP
authors.lastname: Pekola
authors.affiliation: University of Helsinki, Department of Mathematics and Statistics, P.O. Box 68, FIN-00014 Helsinki, Finland.
authors.forename: Paolo
authors.initials: P
authors.lastname: Muratore-Ginanneschi
authors.affiliation: University of Helsinki, Department of Mathematics and Statistics, P.O. Box 68, FIN-00014 Helsinki, Finland.
authors.forename: Antti
authors.initials: A
authors.lastname: Kupiainen
authors.affiliation: Department of Physics, University of Oslo, PO Box 1048, Blindern, 0316 Oslo, Norway.|Ioffe Institute, 26 Politekhnicheskaya, St. Petersburg 194021, Russian Federation.
authors.forename: Yuri M
authors.initials: YM
authors.lastname: Galperin