Abstract: A device comprises a superconducting square pulse waveform generator which comprises a self-oscillating circuit that is configured to generate a continuous sequence of square current pulses in response to a single flux quantum (SFQ) pulse applied to an input port of the superconducting square pulse waveform generator. The self-oscillating circuit is responsive to a first direct current (DC) control signal to tune a pulse period of the continuous sequence of square current pulses, and responsive to a second DC control signal to tune a pulse width of the square current pulses.

Abstract: A device comprises a superconducting switch which comprises an impedance tunable element coupled to and between a transmission line and ground. The transmission line couples a first port and a second port having matched impedances. The impedance tunable element comprises a superconducting loop comprising at least one Josephson junction, and is configured to be flux tuned into a first or second impedance state. In the first impedance state, the impedance tunable element shunts the transmission line to ground with an impedance that disrupts the impedance match between the first and second ports to suppress signal transmission between the first and second ports over the transmission line. In the second impedance state, the impedance tunable element shunts the transmission line to ground with an impedance that maintains the impedance match between the first and second ports to allow signal transmission between the first and second ports over the transmission line.

Abstract: A device comprises a superconducting radio frequency (RF) signal generator which comprises a plurality of channels. Each channel is configured to generate a corresponding RF signal with a frequency that is controlled by a corresponding direct current (DC) control signal applied to the channel.

Abstract: A method is provided for fabricating a multilevel wiring structure. A first metallization layer comprising a superconducting metal is formed in a surface of a first substrate. A second substrate is bonded to the first substrate. The second substrate comprises a monocrystalline dielectric material. The second substrate is thinned to form an interlayer dielectric layer which comprises the monocrystalline dielectric material. A second metallization layer comprising a superconducting metal is formed in a surface of the interlayer dielectric layer. The second metallization layer is connected to the first metallization layer by at least one interlayer via in the interlayer dielectric layer.

Abstract: A device comprises a superconducting radio frequency (RF) signal generator which comprises a plurality of channels. Each channel is configured to generate a corresponding RF signal with a frequency that is controlled by a corresponding direct current (DC) control signal applied to the channel.

Abstract: A device comprises a superconducting quantum bit, and a tunable readout resonator coupled to the superconducting quantum bit. The tunable readout resonator comprises a fixed resonator and a tunable element which is coupled to the fixed resonator and which is configured for flux-tuning the tunable readout resonator into at least one of a first state and a second state. The tunable element comprises a superconducting loop which comprises at least two asymmetric Josephson junctions. In the first state, the tunable readout resonator comprises a first resonant frequency that differs from a transition frequency of the superconducting quantum bit by a first detuning value. In the second state, the tunable readout resonator comprises a second resonant frequency that differs from the transition frequency of the superconducting quantum bit by a second detuning value, which is less than the first detuning value.

Abstract: A Traveling Wave Parametric Amplifier (TWPA) transmission line with improved bandwidth includes one or more unit cell. Each unit cell includes a capacitor to a ground and a Josephson junction in series configured to provide inductance and non-linearity. One or more dispersion resonator is coupled to the transmission line. The dispersion resonator is configured to (i) use a first harmonic mode of the resonator for resonant phase matching in the transmission line and (ii) prevent a second mode of the resonator from interacting with an intermodulation product of the transmission line.

Abstract: Devices, systems and/or methods facilitating two qubit readouts are provided. In an embodiment, a system can comprise a data qubit; a coupler coupling the data qubit to a measurement qubit; and a measurement resonator coupled to the measurement qubit, wherein the measurement resonator is capable of transmitting a tone through the resonator to the measurement qubit.

Abstract: A device comprises a Josephson junction traveling-wave parametric circuit. The Josephson junction traveling-wave parametric circuit comprises unit cells which are coupled in series to form a transmission line between an input port and an output port. Each unit cell comprises a series Josephson junction, and a capacitor shunted to ground. An impedance of the unit cells is varied along the transmission line to match an input impedance at the input port to an output impedance at the output port, wherein the input impedance and the output impedance are dissimilar.

Abstract: A Traveling Wave Parametric Amplifier (TWPA) transmission line with improved bandwidth includes one or more unit cell. Each unit cell includes a capacitor to a ground and a Josephson junction in series configured to provide inductance and non-linearity. One or more dispersion resonator is coupled to the transmission line. The dispersion resonator is configured to (i) use a first harmonic mode of the resonator for resonant phase matching in the transmission line and (ii) prevent a second mode of the resonator from interacting with an intermodulation product of the transmission line.

Abstract: A system resets leakage states of a superconducting qubit to a qubit subspace by using a dedicated electrical circuit on a timescale faster than a natural decay process. One system comprises a qubit including a qubit transition frequency and multiple qubit leakage transition frequencies; and a filter circuit coupled to the qubit for leakage mitigation based on the qubit frequency and the multiple qubit leakage transition frequencies, wherein the filter circuit causes dissipation at the leakage transition frequencies while isolating the qubit transition frequency. Another system comprises a qubit including a qubit transition frequency and multiple qubit leakage transition frequencies; and a tunable dissipative cavity circuit coupled to the qubit for leakage mitigation based on the qubit frequency and the multiple qubit leakage transition frequencies, wherein the tunable dissipative cavity circuit causes the leakage transition frequencies to dissipate while isolating the qubit transition frequency.