Fractional transconductance via non-adiabatic topological Cooper pair pumping

TL;DR

This paper proposes a method to realize fractional quantized transconductance in Josephson junction chains, using non-adiabatic Landau-Zener transitions, enabling quantum simulation of complex many-body states.

Contribution

It introduces a theoretical scheme for achieving fractional topological transconductance in superconducting systems, extending topological phenomena beyond integer effects.

Findings

Stable fractional transconductance plateaus achieved via non-adiabatic Landau-Zener transitions.

Robustness of fractional plateaus against disorder demonstrated.

Optimal conditions for observing fractional quantization identified.

Abstract

Many robust physical phenomena in quantum physics are based on topological invariants arising due to intriguing geometrical properties of quantum states. Prime examples are the integer and fractional quantum Hall effects that demonstrate quantized Hall conductances, associated with topology both in the single particle and the strongly correlated many-body limit. Interestingly, the topology of the integer effect can be realized in superconducting multiterminal systems, but a proposal for the more complex fractional counterpart is lacking. In this work, we theoretically demonstrate how to achieve fractional quantized transconductance in an engineered chain of Josephson junctions. Crucially, similar to the stabilization of the conductance plateaus in Hall systems by disorder, we obtain stable transconductance plateaus as a result of non-adiabatic Landau-Zener transitions. We furthermore show that the fractional plateaus are robust to disorder and study the optimal operation regime to observe these effects. Our proposal paves the way for quantum simulation of exotic many-body out-of-equilibrium states in Josephson junction systems.