Abstract: In most common metals, the many-body physics of their electrons can be described in terms of additive, weakly interacting excitations called quasiparticles. However, several examples of metallic states of matter related to the “high” temperature superconductors and other strongly correlated materials exist, in which strong electron-electron interactions near putative quantum critical points or phases lead to very unconventional physics that cannot be described by quasiparticles, even as the electron liquid remains compressible. Accurately taking into account the effects of such interactions has posed a decades-long challenge for the mathematical methods of quantum many-body physics, which have largely relied on the existence of weakly interacting quasiparticles. I will describe my recent work that develops a new mathematical formalism which can accurately describe the physics of these metals without quasiparticles, allowing for the controlled computation of a whole host of experimentally measurable static and dynamic quantities, despite the presence of both strong correlations and disorder. This work further leads to the realization that disorder in the experimental samples may be crucial for describing the essential physics of these strange metals. Time permitting, I will also show that the scrambling of quantum information,as measured by out-of-time-ordered correlators, in large-N models of quantum critical metals with Fermi surfaces occurs at the maximum possible rate, and explicitly demonstrate that this phenomenon is tied to the lack of well-defined quasiparticles in such systems.
Location: ATL 4402