Speaker
Description
In this talk, I will briefly review the projects from my group’s work over the past decade or so in which the functional renormalisation group (FRG) has played a significant role. Most of these concern the theoretical description of non-Fermi-liquid metals (strongly interacting fermionic fluids without Landau quasiparticles), which often occur due to proximity to a quantum critical point. I shall present results on non-Fermi-liquids caused by proximity to a ferromagnetically ordered phase [1], proximity to a Pomeranchuk instability [2], and the presence of a gauge boson [3]. I shall also briefly present some recent results in which the numerical truncated-unity functional renormalisation group (TU-FRG) method is used to predict the phase reconstruction that occurs in the vicinity of a higher-order Van Hove point in the non-interacting band structure of the material [4].
[1] S. P. Ridgway and CAH, “Non-Fermi-Liquid Behavior and Anomalous Suppression of Landau Damping in Layered Metals Close to Ferromagnetism,” Phys. Rev. Lett. 114, 226404 (2015).
[2] M. J. Trott and CAH, “Non-Fermi-liquid fixed points and anomalous Landau damping in a quantum critical metal,” Phys. Rev. B 98, 201113(R) (2018).
[3] T. P. Sheerin and CAH, “Non-Fermi liquid induced by U(1) gauge-field interactions: A functional renormalization group analysis,” Phys. Rev. Research 7, 023216 (2025).
[4] T. P. Sheerin, M. Ramirez, CAH, and L. C. Rhodes, “Engineering correlated phases through manipulation of Van Hove singularities,” arXiv preprint 2608.07714 (2026).