SO(5) critical point in a spin-flavor Kondo device -- Bosonization and refermionization solution

TL;DR

This paper provides a comprehensive bosonization and refermionization analysis of a spin-flavor Kondo system, revealing a unique non-Fermi liquid phase with SO(5) symmetry and detailed phase diagram insights.

Contribution

It offers a complete theoretical description of the exotic properties and phase diagram of the SO(5) symmetric non-Fermi liquid in a spin-flavor Kondo device using bosonization and refermionization techniques.

Findings

Identification of a unique NFL phase with an uncoupled Majorana fermion.

Explanation of T^{3/2} conductance scaling.

Demonstration of NFL stability under symmetry breaking.

Abstract

We investigate a well studied system of a quantum dot coupled to a Coulomb box and leads, realizing a spin-flavor Kondo model. It exhibits a recently discovered non-Fermi liquid (NFL) behavior with emergent SO(5) symmetry. Here, through a detailed bosonization and refermionization solution, we push forward our previous work and provide a consistent and complete description of the various exotic properties and phase diagram. A unique NFL phase emerges from the presence of an uncoupled Majorana fermion from the flavor sector, whereas FL-like susceptibilities result from the gapping out of a pair of Majroana fermions from the spin and flavor sectors. Other properties, such as a $T^{3/2}$ scaling of the conductance, stability under channel or spin symmetry breaking and a re-appearance of NFL behavior upon breaking the particle-hole symmetry, are all accounted for by a renormalization group treatment of the refermionized Majorana model.