The hierarchy of excitation lifetimes in two-dimensional Fermi gases
Author(s)Ledwith, Patrick John.
Hierarchy of excitation lifetimes in 2D Fermi gases
Massachusetts Institute of Technology. Department of Physics.
Leonid S. Levitov.
MetadataShow full item record
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.
Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019Cataloged from PDF version of thesis.Includes bibliographical references (pages 79-81).
DepartmentMassachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology