arXiv:cond-mat/9801015 · Physical Review Letters
Giant Mass and Anomalous Mobility of Particles in a Fermionic System
Achim Rosch, Thilo Kopp
Abstract
We calculate the mobility of a heavy particle coupled to a Fermi sea within a nonperturbative approach valid at all temperatures. The interplay of particle recoil and of strong-coupling effects, leading to the orthogonality catastrophe for an infinitely heavy particle, is carefully taken into account. We find two novel types of strong-coupling effects: a new low-energy scale ${T}^{*}$ and a giant mass renormalization in the case of either near-resonant scattering or a large transport cross section $\ensuremath{\sigma}$, respectively. The mobility is shown to obey two different power laws below and above ${T}^{*}$. For $\ensuremath{\sigma}\ensuremath{\gg}{\ensuremath{\lambda}}_{f}^{2}$, where ${\ensuremath{\lambda}}_{f}$ is the Fermi wavelength, an exponentially large effective mass suppresses the mobility.