Asymmetric Blockade and Multiqubit Gates via Dipole-Dipole Interactions

Because of their strong and tunable interactions, Rydberg atoms can be used to realize fast two-qubit entangling gates. We propose a generalization of a generic two-qubit Rydberg-blockade gate to multiqubit Rydberg-blockade gates that involve both many control qubits and many target qubits simultaneously. This is achieved by using strong microwave fields to dress nearby Rydberg states, leading to asymmetric blockade in which control-target interactions are much stronger than control-control and target-target interactions. The implementation of these multiqubit gates can drastically simplify both quantum algorithms and state preparation. To illustrate this, we show that a 25-atom Greenberger-Horne-Zeilinger state can be created using only three gates with an error of 5.8%.

Automated summary

Rydberg atoms with strong and tunable interactions can be utilized to realize fast two-qubit entangling gates. A generalization of these gates to multiqubit Rydberg-blockade gates involving many control and target qubits simultaneously is proposed, achieved by using strong microwave fields to dress nearby Rydberg states. The implementation of these multiqubit gates has the potential to simplify quantum algorithms and state preparation, as demonstrated by the creation of a 25-atom Greenberger-Horne-Zeilinger state using only three gates with a 5.8% error rate.