Fluctuations are ubiquitous in physics.For a system close to a phase transition, the order parameter fluctuations are strong. In this thesis we study the pair fluctuations in liquid 3He when it is close to the superfluid phase transition. Liquid 3He is a neutral Fermi liquid, which allows zero sound to propagate at low temperatures. We focus on the zero sound properties in the presence of pair fluctuations. The existing theory is based on a heuristic collision integral. Although the zero sound attenuation generated by this collision integral is consistent with experiment, it lacks a microscopic foundation. The motivation of this work is to derive the collision integral from a more microscopic point of view. We investigate two different approaches. The first approach is based on the conventional kinetic equation, and the second one is novel but closer to the fluctuation theory for superconductors. We obtain a collision integral which is qualitatively different from the heuristic one. Furthermore, results beyond the collision integral are obtained. Our results are compared with the existing experiments, and we obtain close agreement on the attenuation.

Creator

• Lin, Wei-Ting

DOI

• https://doi.org/10.21985/n2-tnmy-ej33

Subject

• Condensed matter physics

Language

• en

Alternate Identifier

• etdadmin_upload_863491
• http://dissertations.umi.com/northwestern:15872

Keyword

• pair fluctuations
• liquid 3He
• zero sound

Date created

• 2021-01-01

Resource type

• Dissertation

Rights statement

• In Copyright