Quantum Cellular Automata with a Dual-Species Rydberg Processor

Advanced quantum experiments often require individual-qubit control systems, which can be difficult to implement, and even more challenging to scale as system sizes continue to grow. However, an often-overlooked alternative approach — quantum cellular automata (QCA) — could achieve many of the same results using only globally-applied unitary evolution. QCAs can be universal for quantum computation, can implement a wide range of Floquet-style quantum simulations for explorations of many-body dynamics, and can also present simple protocols for the generation of useful quantum resource states; all without any qubit addressing, besides a single initialization step.

We implement and explore multiple types of QCA on one-dimensional arrays of Rydberg-enabled rubidium and cesium atoms. Using global laser pulses, we investigate dynamics of quasiparticles under an automaton based on the discretized PXP model, and use the quasiparticle behavior to grow GHZ states from separable initial states. We further implement a second QCA protocol, showing parallel generation of Bell states, 17-atom cluster states, and graph-like states with longer-range connectivity. These results showcase that simple, scalable global control systems are still extremely relevant for modern explorations of quantum information and simulation.