Scientists drive quantum systems by applying time-dependent external forces, such as laser or microwave pulses, oscillating electric or magnetic fields, and voltages or currents, to create new quantum phases, study non-equilibrium physics, control qubits in quantum computers, and simulate materials that don't exist naturally. In this process, they have discovered that driven quantum systems typically absorb energy and eventually heat up toward a featureless infinite-temperature state, where coherent structure is lost.
Understanding how fast this heating process occurs and whether it can be controlled has become a challenge in non-equilibrium physics. For example, high-frequency periodic driving is known to delay heating, but much less is known about heating dynamics under more general, non-periodic driving protocols.
To better understand this heating process, scientists from the Institute of Physics of the Chinese Academy of Sciences, along with their collaborators, have conducted a random multipolar driving experiment on a large, two-dimensional superconducting quantum processor, Chuang-tzu 2.0. During the experiment, they observed a long-lived prethermal regime where the system temporarily avoided full thermalization.
The study was published in Nature on January 28.
Chuang-tzu 2.0 consists of 78 qubits arranged in a 6×13 lattice with 137 tunable couplers. The system was initialized in a density-wave configuration and then driven by a sequence of randomly structured control pulses characterized by two parameters—driving order and the duration of each driving unit. By monitoring particle-number imbalance and entanglement entropy growth during time evolution, the researchers tracked how the system absorbed energy over up to 1,000 driving cycles.
They revealed that the system did not heat up immediately. Instead, it entered a prethermal plateau, during which entropy and particle imbalance remained nearly constant before rapid heating set in. The lifetime of this plateau was found to be doubly tunable and follow a clear power-law dependence on the driving frequency with the universal scaling exponent 2n + 1, linking the heating timescale directly to the structure of the random drive.
Further analysis showed that at later times, entanglement spread across the system and obeyed a strong volume-law scaling. In this regime, commonly used classical simulation methods, including tensor-network approaches, failed to reproduce the observed dynamics, highlighting the complexity of the heating process in large driven quantum systems.
This study provides a new way to study thermalization beyond periodic and quasiperiodic protocols. The observation of a tunable prethermal plateau and its scaling behavior reveals the constraints for theoretical descriptions of driven many-body systems. The emergence of volume-law entanglement at later times highlights the growing gap between experimental quantum simulators and classical numerical approaches in modeling long-time non-equilibrium dynamics.
Nature
Prethermalization by random multipolar driving on a 78-qubit processor
28-Jan-2026