Spin dynamics in spin-polarized Fermi systems

Abstract

We present a simple description of transverse dynamics of dilute Fermi systems in terms of statistical quasiparticles. We give explicit expressions for the quasiparticle interaction function and collision integral at arbitrary temperatures, and discuss the implications of this approach in classical and degenerate regions, including the quantum gases. The results provide an unexpected explanation for the zero-temperature attenuation in transverse spin dynamics and peculiar I2-terms in molecular field as imaginary (pole) and real (principal) parts of the quasiparticle interaction function.