Observation of strong and weak thermalization in a superconducting quantum processor

TL;DR

This study experimentally investigates thermalization behaviors in a 12-qubit superconducting quantum processor, distinguishing regimes of strong and weak thermalization through local observables, entanglement measures, and dynamics.

Contribution

It demonstrates the experimental observation of both strong and weak thermalization regimes in a superconducting qubit array, advancing understanding of quantum thermalization processes.

Findings

Local observables converge to thermal expectation in strong thermalization.

Oscillations around the thermal value characterize weak thermalization.

Entanglement entropy and concurrence distinguish thermalization regimes.

Abstract

We experimentally study the ergodic dynamics of a 1D array of 12 superconducting qubits with a transverse field, and identify the regimes of strong and weak thermalization with different initial states. We observe convergence of the local observable to its thermal expectation value in the strong-thermalizaion regime. For weak thermalization, the dynamics of local observable exhibits an oscillation around the thermal value, which can only be attained by the time average. We also demonstrate that the entanglement entropy and concurrence can characterize the regimes of strong and weak thermalization. Our work provides an essential step towards a generic understanding of thermalization in quantum systems.