Zero and first sound in normal fermi systems

Shohei Watabe, Aiko Osawa, Tetsuro Nikuni

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


On the basis of a moment method, general solutions of a linearized Boltzmann equation for a normal Fermi system are investigated. In particular, we study the sound velocities and damping rates as functions of the temperature and the coupling constant. In the extreme limits of collisionless and hydrodynamic regimes, eigenfrequency of sound mode obtained from the moment equations reproduces the well-known results of zero sound and first sound. In addition, the moment method can describe crossover between those extreme limits at finite temperatures. Solutions of the moment equations also involve a thermal diffusion mode. From solutions of these equations, we discuss excitation spectra corresponding to the particle-hole continuum as well as collective excitations. We also discuss a collective mode in a weak coupling case.

Original languageEnglish
Pages (from-to)773-805
Number of pages33
JournalJournal of Low Temperature Physics
Issue number5-6
Publication statusPublished - 2010 Mar
Externally publishedYes


  • First sound
  • Moment method
  • Normal Fermi gas
  • Sound propagation
  • Zero sound

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • General Materials Science
  • Condensed Matter Physics


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