Physics

Quantum dynamics

Qubit

Mathematics

Quantum phase transition

Rydberg atom

Statistical physics

Statistics

Phase transition

Quantum simulator

Ionization

Computer science

Spin (aerodynamics)

Quantum computer

Quantum mechanics

Realization (probability)

Rydberg formula

Quantum phases

Quantum

Thermodynamics

Nature

Controllable, coherent many-body systems can provide insights into the fundamental properties of quantum matter, enable the realization of new quantum phases and could ultimately lead to computational systems that outperform existing computers based on classical approaches. Here we demonstrate a method for creating controlled many-body quantum matter that combines deterministically prepared, reconfigurable arrays of individually trapped cold atoms with strong, coherent interactions enabled by excitation to Rydberg states. We realize a programmable Ising-type quantum spin model with tunable interactions and system sizes of up to 51 qubits. Within this model, we observe phase transitions into spatially ordered states that break various discrete symmetries, verify the high-fidelity preparation of these states and investigate the dynamics across the phase transition in large arrays of atoms. In particular, we observe robust many-body dynamics corresponding to persistent oscillations of the order after a rapid quantum quench that results from a sudden transition across the phase boundary. Our method provides a way of exploring many-body phenomena on a programmable quantum simulator and could enable realizations of new quantum algorithms. Programmable quantum simulations of many-body systems are demonstrated using a reconfigurable array of 51 individually trapped cold atoms with strong, coherent interactions controlled via excitation to Rydberg states. Richard Feynman proposed the quantum computer in 1982 as a technique for simulating states of matter and the various complex interactions that occur within these systems. In the past few years, quantum simulators have become a reality, with several different qubit approaches. For example, small numbers of individually controlled qubits have already been used to simulate molecules and quantum magnets. However, it has remained a challenge to perform tasks that are beyond the capabilities of classical computers. In this issue, two papers demonstrate quantum simulators with an unprecedentedly high number of controlled qubits. Mikhail Lukin and colleagues used 51 cold Rydberg atoms and Christopher Monroe and colleagues used 53 trapped ions to study phase transitions in Ising-type quantum magnets. Both groups observed novel many-body interactions that are computationally intractable with classical computers.

Probing many-body dynamics on a 51-atom quantum simulator