Northrop Grumman Systems Corporation

James Redding Medford

Anthony Joseph Przybysz

John Xavier Przybysz

Zachary Keane

Alexander Marakov

Aaron Christopher Lee

Jeffrey D Botimer

Andrew Paul Lisiewski

Justin Tyler Mroczkowski

A radio frequency (RF) transmission line system for a multi-thermal environment and method for fabricating the same are provided. In one example, an RF transmission line system a transmission line conductor configured to cooperate to propagate an RF signal from a first thermal environment to a second thermal environment. The first thermal environment has a first temperature and the second thermal environment has a second temperature less than the first temperature. The RF transmission line system also includes a ground plane and a dielectric material that is coupled between the transmission line conductor and the ground plane. The RF transmission line system further includes a galvanic connected resonant structure that electrically couples the transmission line conductor to the ground plane.

Radio frequency transmission line system for a multi-thermal environment

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.

Thermal transition filter for a superconducting circuit system

Systems and methods are provided for resetting a qubit comprising a superconducting loop and a compound Josephson junction. A first bias flux is provided to the superconducting loop. A second bias flux is provided to the compound Josephson junction. Each of the first bias flux and the second bias flux are provided such that a given excited state of the qubit is near a top of a potential barrier associated with a potential of the qubit. A continuous microwave signal is generated having a frequency equal to a transition frequency between an other excited state of the qubit and the given excited state.

Microwave-based reset of persistent current qubits

Systems and methods are provided for flux control of a qubit. A quantum system includes a microwave transmitter configured to provide a continuous microwave tone, and a qubit configured such that transition energy of the qubit between a ground state of the qubit and a first excited state of the qubit is tunable via an applied flux. The qubit also has an inductive element responsive to the continuous microwave tone to produce a Rabi oscillation within the qubit. A flux source is configured to apply a flux to the qubit to selectively tune the transition energy of the qubit, such that the transition energy of the qubit can be tuned to a frequency of the Rabi oscillation or detuned from the Rabi oscillation.

Flux control of qubit under resonant excitation

Systems and methods are provided for flux control of a qubit. A quantum system includes a microwave transmitter configured to provide a continuous microwave tone, and a qubit configured such that a portion of an energy spectrum of the qubit is responsive to an applied flux. The qubit also has an inductive element responsive to the continuous microwave tone to produce a Rabi oscillation within the qubit. A flux source is configured to apply a flux to the qubit.

A push-pull tunable coupler includes a push transformer, a pull transformer and two compound Josephson junctions arranged in upper and lower branches. Absent biasing, the balanced push and pull of current between the branches causes current from a first object to circulate within a loop and not to be coupled to a second object. Biasing of at least one of the compound Josephson junctions unbalances the push and pull of current in the branches to couple the first and second objects. The coupler has reduced sensitivity to differential-mode noise around the off state, is completely insensitive to common-mode noise, and is capable of inverting the coupled signal with appropriate relative biasing of the compound Josephson junctions.

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Baltimore, MD, United States of America

James Redding Medford