Abstract: A quantum computing system, method and computer readable storage medium involve tuning a whispering-gallery mode optical resonator to support a resonance frequency associated with a transition frequency of an atom. Operation of a laser is controlled to cause the atom to be trapped adjacent the optical resonator and within the evanescent field portion. Based on an atom presence signal from an optical atom presence detector, an indication is provided that the atom is trapped adjacent the optical resonator. A frequency of a cooling laser is controlled to cool the atom, and the optical resonator is configured to define a closed loop-like mode including an evanescent field portion. The trapping laser is configured to cause the atom to be trapped adjacent the whispering-gallery mode resonator, and the cooling laser is configured to manipulate a state of the atom to thereby cool the atom.

Abstract: A quantum computing system comprises a plurality of photonic cavities, a plurality of coupling locations for quantum emitter positioning, a photon generator configured to supply photons to the plurality of photonic cavities, and a plurality of photon output channels downstream of the plurality of cavities to output a graph state. Each coupling location is associated with a differing one of the plurality of photonic cavities. Quantum emitters associated with each coupling location are configured to mediate interactions between consecutive incoming photonic qubits to generate the graph state, and the photonic cavities are configured to couple photonic qubits to the quantum emitters.

Abstract: Generating photonic graph states includes positioning a plurality of quantum emitters at a plurality of coupling sites associated with a plurality of cavities and initializing a state of a quantum emitter qubit associated with each of the plurality of quantum emitters. Photonic qubits are transmitted toward the plurality of the quantum emitters a first instance transmission for generating an entangling gate between the photonic qubits and the quantum emitter qubit in order to entangle the quantum emitter qubit and the photonic qubits. Following the first instance transmission, photonic qubits are transmitted toward the plurality of quantum emitters in a one second instance transmission for generating a SWAP gate between the photonic qubits and the quantum emitter qubits to map the quantum emitter qubits to photonic qubits.

Abstract: A quantum computing system includes a first resonator couplable to a first alkali atom, a second resonator couplable to a second alkali atom, and lasers for trapping, cooling, and manipulating the first alkali atom and the second alkali atom. Detectors detect a presence of the trapped first alkali atom and the trapped second alkali atom, and a processor is configured to receive at least one input signal from at least one of the detectors, the input signal indicating a presence of the trapped first alkali atom and the trapped second alkali atom, and, based on the received input, control at least some of the lasers to manipulate at least one of the trapped first alkali atom and the trapped second alkali atom to thereby generate photonic qubits using the trapped first alkali atom or generate entanglement between photonic qubits transmitted to the trapped second alkali atom.

Abstract: A quantum computing system, method and computer readable storage medium involve tuning a whispering-gallery mode optical resonator to support a resonance frequency associated with a transition frequency of an atom. Operation of a laser is controlled to cause the atom to be trapped adjacent the optical resonator and within the evanescent field portion. Based on an atom presence signal from an optical atom presence detector, an indication is provided that the atom is trapped adjacent the optical resonator. A frequency of a cooling laser is controlled to cool the atom, and the optical resonator is configured to define a closed loop-like mode including an evanescent field portion. The trapping laser is configured to cause the atom to be trapped adjacent the whispering-gallery mode resonator, and the cooling laser is configured to manipulate a state of the atom to thereby cool the atom.

Abstract: A quantum computing system comprises a plurality of photonic cavities, a plurality of coupling locations for quantum emitter positioning, a photon generator configured to supply photons to the plurality of photonic cavities, and a plurality of photon output channels downstream of the plurality of cavities to output a graph state. Each coupling location is associated with a differing one of the plurality of photonic cavities. Quantum emitters associated with each coupling location are configured to mediate interactions between consecutive incoming photonic qubits to generate the graph state, and the photonic cavities are configured to couple photonic qubits to the quantum emitters.

Abstract: A quantum computing system includes a first silicon nitride resonator couplable to a first alkali atom, a second silicon resonator couplable to a second alkali atom, and a plurality of lasers for trapping, cooling, and manipulating the first alkali atom and the second alkali atom. Detectors detect a presence of the trapped first alkali atom and the trapped second alkali atom, and a processor is configured to receive at least one input signal from at least one of the detectors, the input signal indicating a presence of the trapped first alkali atom and the trapped second alkali atom, and, based on the received input, control at least some of the plurality of lasers to manipulate at least one of the trapped first alkali atom and the trapped second alkali atom to thereby generate photonic qubits using the trapped first alkali atom or generate entanglement between photonic qubits transmitted to the trapped second alkali atom.

Abstract: A quantum computing system includes a first silicon nitride resonator couplable to a first alkali atom, a second silicon resonator couplable to a second alkali atom, and a plurality of lasers for trapping, cooling, and manipulating the first alkali atom and the second alkali atom. Detectors detect a presence of the trapped first alkali atom and the trapped second alkali atom, and a processor is configured to receive at least one input signal from at least one of the detectors, the input signal indicating a presence of the trapped first alkali atom and the trapped second alkali atom, and, based on the received input, control at least some of the plurality of lasers to manipulate at least one of the trapped first alkali atom and the trapped second alkali atom to thereby generate photonic qubits using the trapped first alkali atom or generate entanglement between photonic qubits transmitted to the trapped second alkali atom.

Abstract: Generating photonic graph states includes positioning a plurality of quantum emitters at a plurality of coupling sites associated with a plurality of cavities and initializing a state of a quantum emitter qubit associated with each of the plurality of quantum emitters. Photonic qubits are transmitted toward the plurality of the quantum emitters a first instance transmission for generating an entangling gate between the photonic qubits and the quantum emitter qubit in order to entangle the quantum emitter qubit and the photonic qubits. Following the first instance transmission, photonic qubits are transmitted toward the plurality of quantum emitters in a one second instance transmission for generating a SWAP gate between the photonic qubits and the quantum emitter qubits to map the quantum emitter qubits to photonic qubits.

Abstract: Techniques for providing hardware-efficient fault-tolerant quantum operations are provided. In some aspects a cavity and an ancilla transmon are used to implement a quantum operation by encoding a logical qubit using more than two energy levels of the cavity, encoding information using more than two energy levels of the ancilla transmon, and creating an interaction between the cavity and the ancilla transmon that decouples at least one error type in the ancilla transmon from the cavity.

Abstract: Techniques for providing hardware-efficient fault-tolerant quantum operations are provided. In some aspects a cavity and an ancilla transmon are used to implement a quantum operation by encoding a logical qubit using more than two energy levels of the cavity, encoding information using more than two energy levels of the ancilla transmon, and creating an interaction between the cavity and the ancilla transmon that decouples at least one error type in the ancilla transmon from the cavity.

Abstract: A switch activated by a single control photon for routing a single target photon from either of two switch inputs to either of two switch outputs. The device is based on a single quantum emitter, such as an atom, coupled to a fiber-coupled, chip-based optical micro-resonator. A single reflected control photon toggles the switch from high reflection to high transmission mode, with no additional control fields required. The control and target photons are both in-fiber and practically identical, for compatibility with scalable architectures for quantum information processing.

Abstract: A switch activated by a single control photon for routing a single target photon from either of two switch inputs to either of two switch outputs. The device is based on a single quantum emitter, such as an atom, coupled to a fiber-coupled, chip-based optical micro-resonator. A single reflected control photon toggles the switch from high reflection to high transmission mode, with no additional control fields required. The control and target photons are both in-fiber and practically identical, for compatibility with scalable architectures for quantum information processing.