Quantum Approximate Optimization

Abstract

In a general aspect, a computing system is configured to execute a quantum approximate optimization algorithm. In some aspects, a control system identifies a pair of qubit devices in a quantum processor. The quantum processor includes a connection that provides coupling between the pair of qubit devices. ZZ coupling between the pair of qubit devices is activated to execute a cost function defined in the quantum approximate optimization algorithm. The cost function is associated with a maximum cut problem, and the ZZ coupling is activated by allowing the pair of qubits to evolve under a natural Hamiltonian for a time period τ. One or more of the pair of qubit devices is measured to obtain an output from an execution of the quantum approximate optimization algorithm.

1 . A quantum computing method comprising:
 by operation of a control system in a quantum computing system, identifying a pair of qubit devices in a quantum processor, wherein the quantum processor comprises a connection that provides coupling between the pair of qubit devices;   activating a coupling between the pair of qubit devices to execute a cost function defined in a quantum approximate optimization algorithm, the cost function being associated with a maximum cut problem, wherein the coupling is activated by allowing the pair of qubits to evolve under a natural Hamiltonian for a time period τ; and   measuring one or more of the pair of qubit devices to obtain an output from an execution of the quantum approximate optimization algorithm.   
     
     
         2 - 24 . (canceled)