SO(5) non-Fermi liquid in a Coulomb box device

TL;DR

This paper predicts a novel SO(5) symmetry Kondo effect in a quantum dot device, leading to a non-Fermi liquid state with unique robustness and tunability, and discusses its experimental signatures.

Contribution

It introduces an exotic SO(5) symmetry Kondo effect in a standard nanodevice, revealing a new non-Fermi liquid phase with distinctive properties.

Findings

Identifies an SO(5) non-Fermi liquid state in a Coulomb box device.

Shows robustness of the NFL state against certain symmetry breakings.

Describes continuous evolution to two-channel Kondo states via gate tuning.

Abstract

Non-Fermi liquid (NFL) physics can be realized in quantum dot devices where competing interactions frustrate the exact screening of dot spin or charge degrees of freedom. We show that a standard nanodevice architecture, involving a dot coupled to both a quantum box and metallic leads, can host an exotic SO(5) symmetry Kondo effect, with entangled dot and box charge and spin. This NFL state is surprisingly robust to breaking channel and spin symmetry, but destabilized by particle-hole asymmetry. By tuning gate voltages, the SO(5) state evolves continuously to a spin and then "flavor" two-channel Kondo state. The expected experimental conductance signatures are highlighted.