Novel duality in disorder driven local quantum criticality

TL;DR

This paper uncovers a novel duality and enhanced symmetry at the quantum critical point in a disordered Kondo system, revealing a new perspective on electron fractionalization and critical impurity dynamics.

Contribution

It introduces a new duality between Kondo singlet and local moment phases and proposes an O(4) symmetry at the quantum critical point, extending beyond traditional frameworks.

Findings

Critical exponents for charge and spin susceptibilities are identical.

Identification of an O(4) symmetry at the quantum critical point.

Proposal of electron fractionalization via topological excitations.

Abstract

We find that competition between random Kondo and random magnetic correlations results in a quantum phase transition from a local Fermi liquid to a spin liquid. The local charge susceptibility turns out to have exactly the same critical exponent as the local spin susceptibility, suggesting novel duality between the Kondo singlet phase and the critical local moment state beyond the Landau-Ginzburg-Wilson symmetry breaking framework. This leads us to propose an enhanced symmetry at the local quantum critical point, described by an O(4) vector for spin and charge. The symmetry enhancement serves mechanism of electron fractionalization in critical impurity dynamics, where such fractionalized excitations are identified with topological excitations.