Self-generated locality near a ferromagnetic quantum-critical point

TL;DR

This paper investigates the behavior of interacting fermions near a ferromagnetic quantum-critical point, revealing a self-generated locality that prevents quasiparticle effective mass divergence before the transition.

Contribution

It introduces the concept of self-generated locality near a ferromagnetic quantum-critical point, showing how fermionic self-energy behavior changes close to criticality.

Findings

Landau damping is a relevant perturbation near FQCP

Fermionic self-energy transitions from momentum to frequency dependence near the transition

Quasiparticle effective mass does not diverge before reaching FQCP

Abstract

We analyze the behavior of interacting fermions near a ferromagnetic Stoner instability. We show that the Landau damping of the spin susceptibility is a relevant perturbation near a ferromagnetic quantum-critical point (FQCP). We argue that, as the system approaches a FQCP, the fermionic self-energy crosses over from predominantly momentum dependent away from the transition to predominantly frequency dependent in the immediate vicinity of the transition. We argue that due to this self-generated locality, the quasiparticle effective mass does not diverge before a FQCP is reached.