Abstract: A hybrid quantum system performs high-fidelity quantum state transduction between a superconducting (SC) microwave qubit and the ground state spin system of a solid-state artificial atom. This transduction is mediated via an acoustic bus connected by piezoelectric transducers to the SC microwave qubit. For SC circuit qubits and diamond silicon vacancy centers in an optimized phononic cavity, the system can achieve quantum state transduction with fidelity exceeding 99% at a MHz-scale bandwidth. By combining the complementary strengths of SC circuit quantum computing and artificial atoms, the hybrid quantum system provides high-fidelity qubit gates with long-lived quantum memory, high-fidelity measurement, large qubit number, reconfigurable qubit connectivity, and high-fidelity state and gate teleportation through optical quantum networks.

Abstract: Qubit allocation for noisy intermediate-scale quantum computers is provided. A quantum circuit comprises a plurality of logical qubits. A hardware specification comprising a connectivity graph of a plurality of physical qubits. A directed acyclic allocation graph is determined based on the plurality of logical qubits and the connectivity graph. The allocation graph comprises a node for each possible allocation of the plurality of logical qubits to the plurality of physical qubits, each allocation having a fidelity, and a plurality of directed edges, each edge connecting to its corresponding first node from its corresponding second node, the first node corresponding to a first allocation, the second node corresponding to a sub-allocation of the first allocation. The allocation graph is searched for a weighted shortest path from a root node of the allocation graph to a leaf node of the allocation graph. The allocation corresponding to the weighted shortest path is outputted.

Abstract: Devices comprising dipole-coupled defects for use as entangled photon pair sources are provided.

Abstract: Devices comprising dipole-coupled defects for use as entangled photon pair sources are provided.

Abstract: A hybrid quantum system performs high-fidelity quantum state transduction between a superconducting (SC) microwave qubit and the ground state spin system of a solid-state artificial atom. This transduction is mediated via an acoustic bus connected by piezoelectric transducers to the SC microwave qubit. For SC circuit qubits and diamond silicon vacancy centers in an optimized phononic cavity, the system can achieve quantum state transduction with fidelity exceeding 99% at a MHz-scale bandwidth. By combining the complementary strengths of SC circuit quantum computing and artificial atoms, the hybrid quantum system provides high-fidelity qubit gates with long-lived quantum memory, high-fidelity measurement, large qubit number, reconfigurable qubit connectivity, and high-fidelity state and gate teleportation through optical quantum networks.

Abstract: Qubit allocation for noisy intermediate-scale quantum computers is provided. In various embodiments, a description of a quantum circuit is received. The quantum circuit comprises a plurality of logical qubits. A hardware specification is received. The hardware specification comprises a connectivity graph of a plurality of physical qubits. A directed acyclic allocation graph is determined based on the plurality of logical qubits and the connectivity graph. The allocation graph comprises a node for each possible allocation of the plurality of logical qubits to the plurality of physical qubits, each allocation having a fidelity, and a plurality of directed edges, each edge connecting to its corresponding first node from its corresponding second node, the first node corresponding to a first allocation, the second node corresponding to a sub-allocation of the first allocation.