The hierarchy of excitation lifetimes in two-dimensional Fermi gases
Name
1132288490-MIT.pdf
Size
5.33 MB
Format
Adobe PDF
Checksum (MD5)
dff2adc08fcecdf723f886ae9208f678
Author(s)
Ledwith, Patrick John.
Advisor(s)
Leonid S. Levitov.
Alternative Title
Hierarchy of excitation lifetimes in 2D Fermi gases
Date Issued
2019
Publisher
Massachusetts Institute of Technology
Abstract
In this thesis we show that omentum-conserving quasiparticle collisions in two-dimensional Fermi gases give rise to a large family of exceptionally long-lived excitation modes. The lifetimes of these modes exceed by a factor (TF/T)2 >> 1 the conventional Landau Fermi-liquid lifetimes T ~ TF/T2. The long-lived modes have a distinct angular structure, taking the form of cos m6 and sin mO with odd m values for a circular Fermi surface, with relaxation rate dependence on m of the form m4 log m, valid at not-too-large m. In contrast, the even-m harmonics feature conventional lifetimes with a weak m dependence. The long-time dynamics, governed by the long-lived modes, takes the form of angular (super)diffusion over the Fermi surface. Altogether, this leads to unusual long-time memory effects, defining an intriguing transport regime that lies between the conventional ballistic and hydrodynamic regimes.
Description
Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 79-81).
Subjects
Physics.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.
Persistent DSpace Link
