Abstract: One aspect of the present invention includes a reciprocal quantum logic (RQL) readout system. The system includes an input stage on which a read pulse is provided and an output stage configured to propagate an output pulse. The system also includes an RQL comparator comprising a first Josephson junction and a second Josephson junction that are coupled to a qubit. A bias current switches between a first Josephson junction in a first quantum state of the qubit and a second Josephson junction in a second quantum state of the qubit. The first Josephson junction triggers to provide the output pulse on the output stage in the first quantum state in response to the read pulse and the second Josephson junction triggers to provide no output pulse on the output stage in the second quantum state in response to the read pulse.

Abstract: A superconducting switch system is provided that includes a filter network having an input portion and an output portion, and a variable inductance coupling element that couples the input portion to the output portion. The variable inductance coupling element has a first inductance that allows a desired portion of an input signal to pass from the input portion to the output portion as an output signal, and a second inductance state that suppresses the input signal from passing from the input portion to the output portion. The superconducting switch system further comprises a switch controller configured to control the switching of the variable inductance coupling element between the first inductance state and the second inductance state.

Abstract: One example includes a superconducting phase-shift system. The system includes an all-pass filter comprising at least one variable inductance element. The all-pass filter can be configured to receive an input signal and to provide the input signal as an output signal that is phase-shifted relative to the input signal based on a variable inductance provided by each of the at least one variable inductance element. The system can further include a phase controller configured to provide a phase-control current to control the variable inductance of the at least one variable inductance element based on a characteristic of the phase-control current.

Abstract: Systems and methods are provided for quantum error correction. A quantum system includes an array of qubits configured to store an item of quantum information. The array of qubits includes a plurality of data qubits and a plurality of measurement qubits configured to extract a syndrome representing agreement among the plurality of data qubits. The quantum system further includes an integrated circuit comprising validation logic configured to determine if the syndrome is valid, decoding logic configured to determine evaluate the syndrome to determine location of errors within the plurality of data qubits, and an error register configured to store locations of the determined errors.

Abstract: Quantum systems are provided, including a qubit and a transmission line resonator having an associated resonant wavelength. A coupling capacitor is configured to capacitively couple the qubit to the transmission line resonator. A transformer is configured to inductively couple the qubit to the transmission line resonator. A selected one of an associated capacitance of the coupling capacitor and an associated mutual inductance of the transformer is a function of a location of the qubit along the transmission line resonator.

Abstract: One embodiment describes a Josephson current source system. The system includes a flux-shuttle loop comprising a plurality of stages arranged in a series loop. Each of the plurality of stages includes at least one Josephson junction. The flux-shuttle loop can be configured, when activated, to sequentially trigger the at least one Josephson junction in each of the plurality of stages about the flux-shuttle loop in response to an inductively-coupled AC clock signal to generate a DC output current provided through an output inductor. The system also includes a flux injector system that is configured to activate the flux-shuttle loop. The flux injector system is further configured to automatically deactivate the flux-shuttle loop in response to an amplitude of the DC output current increasing to a predetermined deactivation threshold.

Abstract: Embodiments are directed to doubly balanced superconducting mixers and to methods for modulating a radio frequency signal using multiple tunable inductive elements in a doubly balanced superconducting mixer. In one scenario, a doubly balanced superconducting mixer is provided which includes an input port that receives an signal. The doubly balanced superconducting mixer further includes an IF control signal, a DC control signal and a filter that includes a first inner filter stage and a second inner filter stage. The first and second inner stages are coupled via a ring of tunable inductive elements, and are further inductively coupled to outer filter stages. The doubly balanced superconducting mixer further includes a controller that modulates the RF signal using the IF control signal and the DC control signal to tune the ring of tunable inductive elements to control transmission of the RF signal through the first and second inner filter stages.

Abstract: A system is provided for multiplexed readout of qubits. The system comprises a plurality of bandpass (BP) filter resonant sections that are each coupled to a different respective point on a read line, wherein each BP filter resonant section is coupleable to a respective qubit through a respective qubit readout resonator. The system further comprises a plurality of tunable couplers, wherein each tunable coupler is coupled between a respective BP filter resonant section and a qubit readout resonator, and a coupling controller that controls the coupling strength of each qubit to the read line by controlling the impedance of each tunable coupler of the plurality of tunable couplers.

Abstract: A superconducting switch system is provided that includes a filter network having a first SQUID coupled to a second SQUID via a common node, an input port coupled to the common node, a first output port coupled to the first SQUID, and a second output port coupled to the second SQUID. The superconducting switch system also includes a switch controller configured to control an amount of induced current through the first SQUID and the second SQUID to alternately switch the first and second SQUIDS between first inductance states in which a desired bandwidth portion of a signal provided at the input terminal passes to the first output terminal and is blocked from passing to the second output terminal, and second inductance states in which the desired bandwidth portion of the input signal passes to the second output terminal and is blocked from passing to the first output terminal.

Abstract: Systems and methods are provided for a hybrid qubit circuit assembly is provided. A first plural set of Josephson junctions is arranged in series on a first path between two nodes of a circuit. A second plural set of Josephson junctions is arranged in parallel with one another to form a direct current superconducting quantum interference device (DC SQUID). The DC SQUID is in parallel with the first plural set of Josephson junctions. A capacitor is in parallel with each of the first plural set of Josephson junctions and the DC SQUID.

Abstract: One embodiment describes a Josephson current source system. The system includes a flux-shuttle loop that is inductively coupled with an AC input signal. The flux-shuttle loop includes a plurality of Josephson junctions spaced about the flux-shuttle loop and being configured, when activated, to sequentially trigger the plurality of Josephson junctions about the flux-shuttle loop in response to the AC input signal to generate a DC output current provided through an output inductor. The system also includes a flux injector that is configured to selectively activate and deactivate the flux-shuttle loop in response to an input signal to control an amplitude of the DC output current.

Abstract: One aspect of the present invention includes a reciprocal quantum logic (RQL) readout system. The system includes an input stage on which a read pulse is provided and an output stage configured to propagate an output pulse. The system also includes an RQL comparator comprising a first Josephson junction and a second Josephson junction that are coupled to a qubit. A bias current switches between a first Josephson junction in a first quantum state of the qubit and a second Josephson junction in a second quantum state of the qubit. The first Josephson junction triggers to provide the output pulse on the output stage in the first quantum state in response to the read pulse and the second Josephson junction triggers to provide no output pulse on the output stage in the second quantum state in response to the read pulse.

Abstract: One aspect of the present invention includes a reciprocal quantum logic (RQL) readout system. The system includes an input stage on which a read pulse is provided and an output stage configured to propagate an output pulse. The system also includes an RQL comparator comprising a first Josephson junction and a second Josephson junction that are coupled to a qubit. A bias current switches between a first Josephson junction in a first quantum state of the qubit and a second Josephson junction in a second quantum state of the qubit. The first Josephson junction triggers to provide the output pulse on the output stage in the first quantum state in response to the read pulse and the second Josephson junction triggers to provide no output pulse on the output stage in the second quantum state in response to the read pulse.

Abstract: Quantum systems are provided, including a qubit and a transmission line resonator having an associated resonant wavelength. A coupling capacitor is configured to capacitively couple the qubit to the transmission line resonator. A transformer is configured to inductively couple the qubit to the transmission line resonator. A selected one of an associated capacitance of the coupling capacitor and an associated mutual inductance of the transformer is a function of a location of the qubit along the transmission line resonator.

Abstract: One example includes a superconducting phase-shift system. The system includes an all-pass filter comprising at least one variable inductance element. The all-pass filter can be configured to receive an input signal and to provide the input signal as an output signal that is phase-shifted relative to the input signal based on a variable inductance provided by each of the at least one variable inductance element. The system can further include a phase controller configured to provide a phase-control current to control the variable inductance of the at least one variable inductance element based on a characteristic of the phase-control current.

Abstract: One embodiment describes a memory cell. The memory cell includes a phase hysteretic magnetic Josephson junction (PHMJJ) that is configured to store one of a first binary logic state corresponding to a binary logic-1 state and a second binary logic state corresponding to a binary logic-0 state in response to a write current and to generate a superconducting phase based on the stored digital state. The memory cell also includes at least one Josephson junction having a critical current that is based on the superconducting phase of the PHMJJ and being configured to provide an output corresponding to the stored digital state in response to a read current.

Abstract: Systems and methods are provided for a hybrid qubit circuit assembly is provided. A first plural set of Josephson junctions is arranged in series on a first path between two nodes of a circuit. A second plural set of Josephson junctions is arranged in parallel with one another to form a direct current superconducting quantum interference device (DC SQUID). The DC SQUID is in parallel with the first plural set of Josephson junctions. A capacitor is in parallel with each of the first plural set of Josephson junctions and the DC SQUID.

Abstract: Systems and methods are provided for applying flux to a quantum-coherent superconducting circuit. In one example, a system includes a long-Josephson junction (LJJ), an inductive loop coupled to the LJJ and inductively coupled to the quantum-coherent superconducting circuit, and a single flux quantum (SFQ) controller configured to apply a SFQ pulse to a first end of the LJJ that propagates the SFQ pulse to a second end of the LJJ, while also applying a flux quantum to the inductive loop resulting in a first value of control flux being applied to the quantum-coherent superconducting circuit.

Abstract: One aspect of the present invention includes a reciprocal quantum logic (RQL) readout system. The system includes an input stage on which a read pulse is provided and an output stage configured to propagate an output pulse. The system also includes an RQL comparator comprising a first Josephson junction and a second Josephson junction that are coupled to a qubit. A bias current switches between a first Josephson junction in a first quantum state of the qubit and a second Josephson junction in a second quantum state of the qubit. The first Josephson junction triggers to provide the output pulse on the output stage in the first quantum state in response to the read pulse and the second Josephson junction triggers to provide no output pulse on the output stage in the second quantum state in response to the read pulse.

Abstract: A system, comprising: a configurable parser that comprises one or more configurable parsing engines, wherein the configurable parser is arranged to receive a packet and to extract from the packet headers associated with a set of protocols that comprises at least one protocol; a packet type detection unit that is arranged to determine a type of the packet in response to the set of protocols; and a configurable data integrity unit that comprises a configuration unit and at least one configurable data integrity engine; wherein the configuration unit is arranged to configure the at least one configurable data integrity engine according to the set of protocols; and wherein the at least one configurable data integrity engine is arranged to perform data integrity processing of the packet to provide at least one data integrity result