Many-body delocalization with a two-dimensional 70-qubit superconducting quantum simulator

TL;DR

This study uses a 70-qubit 2D superconducting quantum simulator to experimentally investigate the stability of many-body localization in higher dimensions, providing evidence for delocalization and supporting avalanche theory predictions.

Contribution

First experimental demonstration of many-body delocalization in a 2D disordered quantum system using a large-scale superconducting quantum simulator.

Findings

Decay of imbalance increases with system size from 21 to 70 qubits.

Experimental results align with avalanche theory predicting MBL instability in 2D.

Established a scalable platform for exploring high-dimensional non-equilibrium quantum phases.

Abstract

Quantum many-body systems with sufficiently strong disorder can exhibit a non-equilibrium phenomenon, known as the many-body localization (MBL), which is distinct from conventional thermalization. While the MBL regime has been extensively studied in one dimension, its existence in higher dimensions remains elusive, challenged by the avalanche instability. Here, using a 70-qubit two-dimensional (2D) superconducting quantum simulator, we experimentally explore the robustness of the MBL regime in controlled finite-size 2D systems. We observe that the decay of imbalance becomes more pronounced with increasing system sizes, scaling up from 21, 42 to 70 qubits, with a relatively large disorder strength, and for the first time, provide an evidence for the many-body delocalization in 2D disordered systems. Our experimental results are consistent with the avalanche theory that predicts the instability of MBL regime beyond one spatial dimension. This work establishes a scalable platform for probing high-dimensional non-equilibrium phases of matter and their finite-size effects using superconducting quantum circuits.