Noise-induced quantum synchronization and maximally entangled mixed states in superconducting circuits

TL;DR

This paper experimentally demonstrates noise-induced quantum synchronization in superconducting qubits, showing that noise can promote entanglement and synchronization, with potential implications for quantum information processing.

Contribution

It reports the first observation of noise-induced quantum synchronization in superconducting qubits and links it to the generation of maximally entangled mixed states.

Findings

End qubits become entangled with nonzero concurrence.

Synchronization persists despite frequency detuning.

Noise facilitates the creation of maximally entangled mixed states.

Abstract

Random fluctuations can lead to cooperative effects in complex systems. We here report the experimental observation of noise-induced quantum synchronization in a chain of superconducting transmon qubits with nearest-neighbor interactions. The application of Gaussian white noise to a single site leads to synchronous oscillations in the entire chain. We show that the two synchronized end qubits are entangled, with nonzero concurrence, and that they belong to a class of generalized Bell states known as maximally entangled mixed states, whose entanglement cannot be increased by any global unitary. We further demonstrate the stability against frequency detuning of both synchronization and entanglement by determining the corresponding generalized Arnold tongue diagrams. Our results highlight the constructive influence of noise in a quantum many-body system and uncover the potential role of synchronization for mixed-state quantum information science.