Random Quantum Circuits

Quantum circuits-built from local unitary gates and local measurements-are a new playground for quantum many-body physics and a tractable setting to explore universal collective phenomena far from equilibrium. These models have shed light on longstanding questions about thermalization and chaos, and on the underlying universal dynamics of quantum information and entanglement. In addition, such models generate new sets of questions and give rise to phenomena with no traditional analog, such as dynamical phase transitions in quantum systems that are monitored by an external observer. Quantum circuit dynamics is also topical in view of experimental progress in building digital quantum simulators that allow control of precisely these ingredients. Randomness in the circuit elements allows a high level of theoretical control, with a key theme being mappings between real-time quantum dynamics and effective classical lattice models or dynamical processes. Many of the universal phenomena that can be identified in this tractable setting apply to much wider classes of more structured many-body dynamics.

Automated summary

Quantum circuits, constructed from local unitary gates and local measurements, have become a useful tool in studying universal collective phenomena in non-equilibrium conditions. These models have provided insights into long-standing questions regarding thermalization, chaos, and the dynamics of quantum information and entanglement. Additionally, they have led to the discovery of new phenomena, such as dynamical phase transitions, that do not have traditional analogues. The randomness of the circuit elements allows for increased theoretical control and the mapping of real-time quantum dynamics to classical lattice models or dynamical processes.