Quantum jumps in the non-Hermitian dynamics of a superconducting qubit

TL;DR

This paper investigates how quantum jumps influence the dynamics and decoherence of a driven non-Hermitian superconducting qubit, revealing enhanced decoherence near exceptional points and implications for quantum sensing and control.

Contribution

It introduces the study of quantum jumps in non-Hermitian superconducting qubits, highlighting their effects on decoherence and adiabatic evolution, which was not previously explored.

Findings

Decoherence rate is enhanced near the exceptional point.

Quantum jumps can cause breakdown of adiabatic evolution.

Quantum jumps play a critical role in non-Hermitian quantum systems.

Abstract

We study the dynamics of a driven non-Hermitian superconducting qubit which is perturbed by quantum jumps between energy levels, a purely quantum effect with no classical correspondence. The quantum jumps mix the qubit states leading to decoherence. We observe that this decoherence rate is enhanced near the exceptional point, owing to the cube-root topology of the non-Hermitian eigenenergies. Together with the effect of non-Hermitian gain/loss, quantum jumps can also lead to a breakdown of adiabatic evolution under the slow-driving limit. Our study shows the critical role of quantum jumps in generalizing the applications of classical non-Hermitian systems to open quantum systems for sensing and control.