Abstract: A method for measuring the quantum state of a resonator includes, exciting an input port of a circuit with signal, measuring a phase shift of the signal at an output port of the circuit, wherein the resonator is coupled to the input and the output ports, and calculating a quantum state of the resonator as a function of the measured phase shift of the signal.

Abstract: A method for determining whether a quantum system comprising a superconducting qubit is occupying a first basis state or a second basis state once a measurement is performed is provided. The method, comprising: applying a signal having a frequency through a transmission line coupled to the superconducting qubit characterized by two distinct, separate, and stable states of differing resonance frequencies each corresponding to the occupation of the first or second basis state prior to measurement; and measuring at least one of an output power or phase at an output port of the transmission line, wherein the measured output power or phase is indicative of whether the superconducting qubit is occupying the first basis state or the second basis state.

Abstract: An apparatus and method for manufacturing a superconducting low-pass filter for quantum computing devices. The apparatus includes a plurality of containers and input and output ports connected to opposite ends of the apparatus. A plurality of coils of superconducting wire are wound using a mandrel. An adhesive is applied to the coils for maintaining a wound state. Each of the coils are positioned in each of the containers and electrically connected to each other with at least one coil being connected to the input port and at least one coil being connected to the output port. The coils are released or expanded from their wound state using an adhesive solvent. The containers are then filled with a conductive polymer and the containers are closed with one or more covers.

Abstract: A method for determining whether a quantum system comprising a superconducting qubit is occupying a first basis state or a second basis state once a measurement is performed is provided. The method, comprising: applying a signal having a frequency through a transmission line coupled to the superconducting qubit characterized by two distinct, separate, and stable states of differing resonance frequencies each corresponding to the occupation of the first or second basis state prior to measurement; and measuring at least one of an output power or phase at an output port of the transmission line, wherein the measured output power or phase is indicative of whether the superconducting qubit is occupying the first basis state or the second basis state.

Abstract: A method (and structure) of coupling a qubit includes locating the qubit near a transmission line approximately at a location corresponding to a node at a predetermined frequency.

Abstract: A method for measuring the quantum state of a resonator includes, exciting an input port of a circuit with signal, measuring a phase shift of the signal at an output port of the circuit, wherein the resonator is coupled to the input and the output ports, and calculating a quantum state of the resonator as a function of the measured phase shift of the signal.

Abstract: An improved persistent current switch design and method of operation are disclosed. By way of example, a persistent current switch circuit comprises a heating element and a switch element located proximate to the heating element, the switch element being substantially formed from a material (by way of example only, titanium) which exhibits a superconducting temperature value below a superconducting temperature value exhibited by a material (by way of example only, aluminum) used to provide a connection to the switch element. The switch element is responsive to the heating element such that the heating element is used to control whether or not the switch element is in a superconducting state. The switch element may also have a folded geometry. Such persistent current switches exhibit low power and low inductance.

Abstract: A method for determining whether a quantum system comprising a superconducting qubit is occupying a first basis state or a second basis state once a measurement is performed is provided. The method, comprising: applying a signal having a frequency through a transmission line coupled to the superconducting qubit characterized by two distinct, separate, and stable states of differing resonance frequencies each corresponding to the occupation of the first or second basis state prior to measurement; and measuring at least one of an output power or phase at an output port of the transmission line, wherein the measured output power or phase is indicative of whether the superconducting qubit is occupying the first basis state or the second basis state.

Abstract: A method (and structure) of coupling a qubit includes locating the qubit near a transmission line approximately at a location corresponding to a node at a predetermined frequency.

Abstract: A method (and structure) of coupling a qubit includes locating the qubit near a transmission line approximately at a location corresponding to a node at a predetermined frequency.

Abstract: A method (and structure) of coupling a qubit includes locating the qubit near a transmission line approximately at a location corresponding to a node at a predetermined frequency.