Fig. 4: Entanglement dynamics and volume-law scaling.
From: Prethermalization by random multipolar driving on a 78-qubit processor
a, Dynamics of the entanglement entropy for different subsystem configurations, involving 4 qubits in the 78-qubit system. All subsystems dynamics enter a long-lived prethermal regime, among which \({\mathcal{A}}\) exhibits pronounced oscillatory dynamics. Inset: the entanglement entropy averaged over the prethermal regime (30 ns ≤ t ≤ 100 ns, denoted between two black vertical dashed lines in a), as a function of volume V for subsystems \({\mathcal{A}}\) and \({\mathcal{B}}\). b, The volume (sV) and the area entanglement entropy (sA) per site, numerically fitted by analysing subsystems of varying volumes and areas at different times. The error bars correspond to 1 s.d. of the fitting parameter. c, Ratio sV/sA at different times, as a quantitative measure to distinguish between the area-law and the volume-law scaling. As time evolves, a clear crossover from the area-law to volume-law scaling is observed around 5–10 ns. Here we use 1-RMD protocol and T = 4 ns to perform the experiment.
