Dephasing-assisted diffusive dynamics in superconducting quantum circuits

TL;DR

This paper demonstrates how controlled dephasing noise induces diffusive dynamics in superconducting qubits, revealing novel phenomena like the Mpemba effect and offering insights into dissipative quantum processes.

Contribution

It experimentally shows dephasing-assisted diffusion and the Mpemba effect in superconducting circuits, advancing understanding of open quantum system dynamics.

Findings

Dephasing noise induces diffusive behavior in qubit arrays.

Localized states relax faster under dephasing, showing Mpemba-like effects.

Controlled dissipation can be used to study open quantum systems.

Abstract

Random fluctuations caused by environmental noise can lead to decoherence in quantum systems. Exploring and controlling such dissipative processes is both fundamentally intriguing and essential for harnessing quantum systems to gain practical advantages and deeper insights. In this work, we first demonstrate the diffusive dynamics assisted by controlled dephasing noise in superconducting quantum circuits, contrasting with coherent evolution. We show that dephasing can give distinct dynamical behavior in a superconducting qubit array with quasiperiodic order. Furthermore, by preparing different excitation distributions in the qubit array, we observe that a more localized initial state relaxes to a uniformly distributed mixed state faster with dephasing noise, illustrating another counterintuitive phenomenon called Mpemba-effect-like quantum dynamics, i.e., a far-from-equilibrium state can relax toward the equilibrium faster. These results deepen our understanding of diffusive dynamics at the microscopic level, and demonstrate controlled dissipative processes as a valuable tool for investigating Markovian open quantum systems.