Density and spin modes in imbalanced normal Fermi gases from collisionless to hydrodynamic regime

Masato Narushima, Shohei Watabe, Tetsuro Nikuni

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


We study the mass-and population-imbalance effect on density (in-phase) and spin (out-of-phase) collective modes in a two-component normal Fermi gas. By calculating the eigenmodes of the linearized Boltzmann equation as well as the density/spin dynamic structure factor, we show that mass-and population-imbalance effects offer a variety of collective mode crossover behaviors from collisionless to hydrodynamic regimes. The mass-imbalance effect shifts the crossover regime to the higher-temperature, and a significant peak of the spin dynamic structure factor emerges only in the collisionless regime. This is in contrast to the case of mass-and population-balanced normal Fermi gases, where the spin dynamic response is always absent. Although the population-imbalance effect does not shift the crossover regime, the spin dynamic structure factor survives both in the collisionless and hydrodynamic regimes.

Original languageEnglish
Article number055202
JournalJournal of Physics B: Atomic, Molecular and Optical Physics
Issue number5
Publication statusPublished - 2018 Jan 29
Externally publishedYes


  • Boltzmann equation
  • collisionless zero sound
  • density (in-phase) mode
  • hydrodynamic first sound
  • mass-and population-imbalance effect
  • spin (out-of-phase) mode
  • two-component normal Fermi gas

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics


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