Abstract: In a general aspect, a microwave quantum circuit includes an on-chip impedance matching circuit. In some cases, a microwave quantum circuit includes a dielectric substrate, a quantum circuit device on the substrate, and an impedance matching circuit device on the substrate. The quantum circuit device includes a Josephson junction, and the impedance matching circuit device is coupled to the quantum circuit device on the substrate.

Abstract: A quantum error-correction technique includes applying a first set of two-qubit gates to qubits in a lattice cell, and applying a second, different set of two-qubit gates to the qubits in the lattice cell. The qubits in the lattice cell include data qubits and ancilla qubits, and the ancilla qubits reside between respective nearest-neighbor pairs of the data qubits. After the first and second sets of two-qubit gates have been applied, measurement outcomes of the ancilla qubits are obtained, and the parity of the measurement outcomes is determined.

Abstract: In a general aspect, a quantum information processing circuit is analyzed. In some implementations, a linear response function of a quantum information processing circuit is generated. A linear circuit model is generated based on the linear response function. A composite circuit model is generated by combining the linear circuit model and a nonlinear circuit model. An operating parameter of the quantum information processing circuit is computed by solving the composite circuit model. In some implementations, an electromagnetic structure solver determines the linear response function based on a circuit specification, a quantum circuit analysis tool calculates the operating parameters, and the circuit specification is modified based on the operating parameters.

Abstract: A quantum computing system that includes a quantum circuit device having at least one operating frequency; a first substrate having a first surface on which the quantum circuit device is disposed; a second substrate having a first surface that defines a recess of the second substrate, the first and second substrates being arranged such that the recess of the second substrate forms an enclosure that houses the quantum circuit device; and an electrically conducting layer that covers at least a portion of the recess of the second substrate.

Abstract: In a general aspect, a microwave quantum circuit includes an on-chip impedance matching circuit. In some cases, a microwave quantum circuit includes a dielectric substrate, a quantum circuit device on the substrate, and an impedance matching circuit device on the substrate. The quantum circuit device includes a Josephson junction, and the impedance matching circuit device is coupled to the quantum circuit device on the substrate.

Abstract: In a general aspect, a qubit device includes two circuit loops. In some aspects, a first circuit loop includes a first Josephson junction, a second circuit loop includes a second Josephson junction, and the first and second loops are configured to receive a magnetic flux that defines a transition frequency of a qubit device. In some aspects, a quantum integrated circuit includes an inductor connected between a first circuit node and a second circuit node; the first Josephson junction connected in parallel with the inductor between the first circuit node and the second circuit node; and the second Josephson junction connected in parallel with the inductor between the first circuit node and the second circuit node.

Abstract: A qubit system includes a substrate layer, a qubit circuit suspended above the substrate layer and fine structure disposed between the qubit circuit and the substrate layer.

Abstract: A quantum computing system includes a quantum circuit device, a substrate having a first surface on which the quantum processing device is disposed, and one or more vias each extending through the substrate. The vias include a material that is a superconducting material during operation of the quantum computing system.

Abstract: In a general aspect, a qubit device includes two circuit loops. In some aspects, a first circuit loop includes a first Josephson junction, a second circuit loop includes a second Josephson junction, and the first and second loops are configured to receive a magnetic flux that defines a transition frequency of a qubit device. In some aspects, a quantum integrated circuit includes an inductor connected between a first circuit node and a second circuit node; the first Josephson junction connected in parallel with the inductor between the first circuit node and the second circuit node; and the second Josephson junction connected in parallel with the inductor between the first circuit node and the second circuit node.

Abstract: In a general aspect, a quantum information processing circuit is analyzed. In some implementations, a linear response function of a quantum information processing circuit is generated. A linear circuit model is generated based on the linear response function. A composite circuit model is generated by combining the linear circuit model and a nonlinear circuit model. An operating parameter of the quantum information processing circuit is computed by solving the composite circuit model. In some implementations, an electromagnetic structure solver determines the linear response function based on a circuit specification, a quantum circuit analysis tool calculates the operating parameters, and the circuit specification is modified based on the operating parameters.

Abstract: A qubit system includes a substrate layer, a qubit circuit suspended above the substrate layer and fine structure disposed between the qubit circuit and the substrate layer.

Abstract: A device includes a housing, at least two qubits disposed in the housing and a resonator disposed in the housing and coupled to the at least two qubits, wherein the at least two qubits are maintained at a fixed frequency and are statically coupled to one another via the resonator, wherein energy levels |03> and |12> are closely aligned, wherein a tuned microwave signal applied to the qubit activates a two-qubit phase interaction.

Abstract: A mechanism relates to a superconducting quantum system. A diamond substrate layer is included. A superconducting quantum device is disposed on the diamond substrate layer. The superconducting quantum device includes a superconducting quantum circuit formed on top a surface of the diamond substrate layer.

Abstract: A quantum information processing system includes a first composite quantum system, a second composite quantum system, a plurality of electromagnetic field sources coupled to the system and an adjustable electromagnetic coupling between the first composite quantum system and the second composite quantum system.

Abstract: A mechanism relates to a superconducting quantum system. A diamond substrate layer is included. A superconducting quantum device is disposed on the diamond substrate layer. The superconducting quantum device includes a superconducting quantum circuit formed on top a surface of the diamond substrate layer.

Abstract: A qubit system includes a substrate layer, a qubit circuit suspended above the substrate layer and fine structure disposed between the qubit circuit and the substrate layer.

Abstract: A qubit system includes a substrate layer, a qubit circuit suspended above the substrate layer and fine structure disposed between the qubit circuit and the substrate layer.

Abstract: A qubit system includes a substrate layer, a qubit circuit suspended above the substrate layer and fine structure disposed between the qubit circuit and the substrate layer.

Abstract: A quantum information processing system includes a waveguide having an aperture, a non-linear quantum circuit disposed in the waveguide and an electromagnetic control signal source coupled to the aperture.

Abstract: A quantum information processing system includes a waveguide having an aperture, a non-linear quantum circuit disposed in the waveguide and an electromagnetic control signal source coupled to the aperture.