QMC Colloquium - Matthew Foster, "Quantum interference of hydrodynamic modes"
Quantum interference of hydrodynamic modes despite Planckian dissipation in a strange metal
Marginal fermi liquid (MFL) phenomenology was invented 30 years ago to describe the "strange metal" phase of the high-Tc superconductors. A key feature was strong ("Planckian") dissipation of quasiparticles, and the concomitant prediction of linear-T resistivity. The latter is considered a key experimental hallmark of strange metallicity now observed in a wide variety of quantum materials.
We construct a consistent transport theory for a MFL, but show that the Planckian dissipation does NOT imply linear-T resistivity. In fact, transport and quasiparticle lifetimes are completely distinct, and moreover confusing them violates charge conservation. Despite this, we show that linear-T resistivity is still possible in our MFL transport theory, but arises from an unanticipated source: elastic quantum interference corrections mediated by interactions (Altshuler-Aronov corrections). The linear-T arises from a very simple and universal mechanism, which is the relaxational form of force-mediating quantum-critical boson modes. I will explain the construction of our theory and the key predictions, including competing mechanisms that can suppress or enhance superconductivity.
Our results appear to imply that a quantum many-body system without well-defined quasiparticles (due to Planckian dissipation) can still exhibit macroscopic quantum coherence in hydrodynamic collective modes.
Host: Johnpierre Paglione
Refreshments 1:30pm 1117 Toll Physics Bldg.