Fractional entropy of multichannel Kondo systems from conductance-charge relations

TL;DR

This paper proposes an indirect method to measure fractional entropy in multichannel charge-Kondo systems using conductance-charge relations, revealing signatures of exotic quasiparticles like Majorana and Fibonacci anyons.

Contribution

It derives new relations connecting charge occupation to conductance in multichannel Kondo systems, enabling experimental detection of fractional entropy and exotic quasiparticles.

Findings

Majorana and Fibonacci anyon quasiparticles are present in existing devices.

Characteristic entropies are measurable through conductance and charge measurements.

The analysis supports the existence of nonlocal degrees of freedom in charge-Kondo systems.

Abstract

Fractional entropy is a signature of nonlocal degrees of freedom, such as Majorana zero modes or more exotic non-Abelian anyons. Although direct experimental measurements remain challenging, Maxwell relations provide an indirect route to the entropy through charge measurements. Here we consider multichannel charge-Kondo systems, which are predicted to host exotic quasiparticles due to a frustration of Kondo screening at low temperatures. In the absence of experimental data for the charge occupation, we derive relations connecting the latter to the conductance, for which experimental results have recently been obtained. Our analysis indicates that Majorana and Fibonacci anyon quasiparticles are well-developed in existing two- and three-channel charge-Kondo devices, and that their characteristic $k_{\rm{B}}\log\sqrt{2}$ and $k_{\rm{B}}\log\frac{1+\sqrt{5}}{2}$ entropies are experimentally measurable.