Abstract: A superconductor system is provided that includes a superconductor device comprising a plurality of superconductor layers and dielectric layers interleaved with the plurality of superconductor layers, wherein at least one superconductor layer is a ground plane. The superconductor device further includes superconductor circuitry that resides within one or more of the plurality of superconductor layers, and one or more active moats extending through the plurality of superconductor layers and the dielectric layers, wherein at least one flux vortex caused by cryogenic cooling can be removed from at least one of the plurality of superconductor layers into the one or more active moats by the activating and deactivating of the one or more active moats.

Abstract: One example includes a superconducting circuit system. The system includes at least one bias input configured to provide a bias current to a superconducting device via at least one superconducting device bias line coupled to the superconducting device during operation of the superconducting device. The system further includes a thermal transition filter system interconnecting the superconducting device bias line and the bias input. The thermal transition filter system provides a current path to divert noise current provided from the bias input away from the superconducting device during a temperature transition from a first temperature to a second temperature. The first temperature is greater than a highest superconducting critical temperature associated with the superconducting circuit system and the second temperature is less than a lowest superconducting critical temperature for the superconducting circuit system.

Abstract: A flux-pump digital-to-analog converter (DAC) includes a ring of Josephson transmission line (JTL) stages. The ring includes multiple injector Josephson junctions (JJs). Each of the multiple injector JJs can be individually activated to inject magnetic flux into the ring in a given AC clock cycle, or controllably deactivated so as not to inject flux during the given AC clock cycle. The flux-pump DAC further includes a load inductor coupled to ring JJs of the ring. The load inductor is configured to store the magnetic flux injected into the ring. Because the flux-pump DAC includes multiple injector JJs arranged around the JTL ring, it can ramp up current loaded into the load inductor faster than a single-injector flux-pump DAC, and with precise, variable controllability of ramp speed so as to provide enhanced adiabaticity.

Abstract: One example includes a superconducting circuit system. The system includes at least one bias input configured to provide a bias current to a superconducting device via at least one superconducting device bias line coupled to the superconducting device during operation of the superconducting device. The system further includes a thermal transition filter system interconnecting the superconducting device bias line and the bias input. The thermal transition filter system provides a current path to divert noise current provided from the bias input away from the superconducting device during a temperature transition from a first temperature to a second temperature. The first temperature is greater than a highest superconducting critical temperature associated with the superconducting circuit system and the second temperature is less than a lowest superconducting critical temperature for the superconducting circuit system.

Abstract: A flux-pump digital-to-analog converter (DAC) includes a ring of Josephson transmission line (JTL) stages. The ring includes multiple injector Josephson junctions (JJs). Each of the multiple injector JJs can be individually activated to inject magnetic flux into the ring in a given AC clock cycle, or controllably deactivated so as not to inject flux during the given AC clock cycle. The flux-pump DAC further includes a load inductor coupled to ring JJs of the ring. The load inductor is configured to store the magnetic flux injected into the ring. Because the flux-pump DAC includes multiple injector JJs arranged around the JTL ring, it can ramp up current loaded into the load inductor faster than a single-injector flux-pump DAC, and with precise, variable controllability of ramp speed so as to provide enhanced adiabaticity.

Abstract: A superconductor system is provided that includes a superconductor device comprising a plurality of superconductor layers and dielectric layers interleaved with the plurality of superconductor layers, wherein at least one superconductor layer is a ground plane. The superconductor device further includes superconductor circuitry that resides within one or more of the plurality of superconductor layers, and one or more active moats extending through the plurality of superconductor layers and the dielectric layers, wherein at least one flux vortex caused by cryogenic cooling can be removed from at least one of the plurality of superconductor layers into the one or more active moats by the activating and deactivating of the one or more active moats.