A parametric traveling wave amplifier (200) is disclosed in which the amplifiers include: a co-planar waveguide, in which the co-planar waveguide includes at least one Josephson junction (210) interrupting a center trace (204) of the co-planar waveguide; and at least one shunt capacitor coupled to the co-planar waveguide, in which each shunt capacitor of the at least one shunt capacitor includes a corresponding superconductor trace (214) extending over an upper surface of the center trace of the co-planar waveguide, and in which a gap separates the superconductor trace from the upper surface of the center trace, and in which the co-planar waveguide including the at least one Josephson junction and the shunt capacitor establish a predefined overall impedance for the traveling wave parametric amplifier.

A parametric traveling wave amplifier (200) is disclosed in which the amplifiers include: a co-planar waveguide, in which the co-planar waveguide includes at least one Josephson junction (210) interrupting a center trace (204) of the co-planar waveguide; and at least one shunt capacitor coupled to the co-planar waveguide, in which each shunt capacitor of the at least one shunt capacitor includes a corresponding superconductor trace (214) extending over an upper surface of the center trace of the co-planar waveguide, and in which a gap separates the superconductor trace from the upper surface of the center trace, and in which the co-planar waveguide including the at least one Josephson junction and the shunt capacitor establish a predefined overall impedance for the traveling wave parametric amplifier.

Superconducting output amplifiers with interstage filters and related methods are described. An example superconducting output amplifier includes a first superconducting output amplifier stage and a second superconducting output amplifier stage. The superconducting output amplifier may further include a first terminal for receiving a first single flux quantum (SFQ) pulse train and coupling the SFQ pulse train to each of the first superconducting output amplifier stage and the second superconducting output amplifier stage. The superconducting output amplifier may further include an interstage filter comprising a damped Josephson junction (JJ) coupled between the first superconducting output amplifier stage and the second superconducting output amplifier stage, where the interstage filter is arranged to reduce distortion in an output voltage waveform generated by the superconducting output amplifier in response to at least the first SFQ pulse train.

Superconducting output amplifiers with interstage filters and related methods are described. An example superconducting output amplifier includes a first superconducting output amplifier stage and a second superconducting output amplifier stage. The superconducting output amplifier may further include a first terminal for receiving a first single flux quantum (SFQ) pulse train and coupling the SFQ pulse train to each of the first superconducting output amplifier stage and the second superconducting output amplifier stage. The superconducting output amplifier may further include an interstage filter comprising a damped Josephson junction (JJ) coupled between the first superconducting output amplifier stage and the second superconducting output amplifier stage, where the interstage filter is arranged to reduce distortion in an output voltage waveform generated by the superconducting output amplifier in response to at least the first SFQ pulse train.

A technique relates to qubit drive and readout. A first lossless microwave switch is connected to a quantum system. A second lossless microwave switch is connectable to the first lossless microwave switch. A quantum-limited amplifier is connectable to the second lossless microwave switch.

A system includes a plurality of superconducting wires connected in parallel with one another. The plurality of superconducting wires includes a first superconducting wire and a second superconducting wire. The plurality of superconducting wires are configured to, while receiving a bias current provided to the parallel combination of the plurality of superconducting wires, operate in a superconducting state in the absence of a trigger current. The first superconducting wire is configured to, while receiving the bias current, transition to a non-superconducting state in response to receiving the trigger current. The second superconducting wire is configured to, while receiving the bias current, transition to a non-superconducting state in response to the first superconducting wire transitioning to the non-superconducting state.

A system includes a plurality of superconducting wires connected in parallel with one another. The plurality of superconducting wires includes a first superconducting wire and a second superconducting wire. The plurality of superconducting wires are configured to, while receiving a bias current provided to the parallel combination of the plurality of superconducting wires, operate in a superconducting state in the absence of a trigger current. The first superconducting wire is configured to, while receiving the bias current, transition to a non-superconducting state in response to receiving the trigger current. The second superconducting wire is configured to, while receiving the bias current, transition to a non-superconducting state in response to the first superconducting wire transitioning to the non-superconducting state.

Devices and/or computer-implemented methods to facilitate a Josephson traveling wave parametric amplifier (JTWPA) device with sideband suppression are provided. According to an embodiment, a device can comprise a plurality of unit cells including at least one Josephson junction and a shunt capacitor. The device can further comprise a plurality of first dispersion resonators coupled to the plurality of unit cells at a first interval. The plurality of first dispersion resonators suppress generation of at least one of a third order harmonic of a pump tone applied to the device, a third order intermodulation product, or a fifth order intermodulation product.

Devices and/or computer-implemented methods to facilitate a Josephson traveling wave parametric amplifier (JTWPA) device with sideband suppression are provided. According to an embodiment, a device can comprise a plurality of unit cells including at least one Josephson junction and a shunt capacitor. The device can further comprise a plurality of first dispersion resonators coupled to the plurality of unit cells at a first interval. The plurality of first dispersion resonators suppress generation of at least one of a third order harmonic of a pump tone applied to the device, a third order intermodulation product, or a fifth order intermodulation product.

Technology is disclosed herein that the enhances the measurability and scalability of qubits in a quantum computing environment. In an implementation, a superconducting amplifier device comprises a parametric amplifier and a tunable coupling between the parametric amplifier and a readout cavity external to the superconducting amplifier device. The tunable coupling allows an entangled signal, associated with a qubit in the readout cavity, to transfer from the readout cavity to the parametric amplifier. The parametric amplifier amplifies the entangled signal to produce an amplified signal as output to a measurement sub-system.