Emergence of non-Landau quasiparticle at geometric quantum criticality

Metals can undergo geometric quantum phase transitions that do not involve change in symmetry or topology. Around geometric quantum critical points, there exist inflection points at which the curvature of Fermi surface vanishes, and quasiparticles exhibit an anomalous decay rate. In this paper, we study a geometric quantum phase transition that divides a globally convex Fermi surface from a Fermi surface with locally concave sections in two dimensions. It is shown that non-Landau quasiparticles with a decay rate that goes as E^α with 1<α<2 as a function of quasiparticle energy E emerge in the presence of short-range interactions.