Abstract: A method, system, and arrangement for resetting qubits are disclosed. An example system includes one or more quantum circuit refrigerators for resetting qubits. Each of the quantum circuit refrigerators includes a tunneling junction and a control input for receiving a control signal. Photon-assisted single-electron tunneling takes place across the respective tunneling junction in response to a control signal. Capacitive or inductive coupling elements between the qubits and the quantum circuit refrigerators couple each qubit to the quantum circuit refrigerator(s). The qubits, quantum circuit refrigerators, and coupling elements are located in a cryogenically cooled environment. A common control signal line to the control inputs crosses into the cryogenically cooled environment from a room temperature environment.

Abstract: A vector signal generator is capable of operating on microwave frequencies. It comprises a microwave resonator, an output for coupling microwave photons out of said microwave resonator, and a Josephson junction or junction array coupled to the microwave resonator for emitting microwave signals into the microwave resonator. A biasing circuit is provided for applying a bias to the Josephson junction or junction array. A tunable attenuator is coupled to said microwave resonator.

Abstract: A three-dimensional superconducting qubit and a method for manufacturing the same are disclosed. In an example, a three-dimensional superconducting qubit comprises a structural base comprising one or more insulating materials, and superconductive patterns on surfaces of the structural base. The superconductive patterns form at least a capacitive part and an inductive part of the three-dimensional superconducting qubit. A first surface of the surfaces of the structural base defines a first plane and a second surface of the surfaces of the structural base defines a second plane, the second plane being oriented differently than the first plane. At least one superconductive pattern of the superconductive patterns extends from the first surface to the second surface.

Abstract: For reading out a state of a qubit, a readout input waveform is injected into a system that comprises an information storage element for storing the state of the qubit and a readout resonator that is electromagnetically coupled to said information storage element. A readout output waveform is extracted from said system and detected. The injection of the readout input waveform takes place through an excitation port that is also used to inject excitation waveforms to the information storage element for affecting the state of the qubit. A phase of the readout input waveform is controllably shifted in the course of injecting it into the system.

Abstract: A vector signal generator is capable of operating on microwave frequencies. It comprises a microwave resonator, an output for coupling microwave photons out of said microwave resonator, and a Josephson junction or junction array coupled to the microwave resonator for emitting microwave signals into the microwave resonator. A biasing circuit is provided for applying a bias to the Josephson junction or junction array. A tunable attenuator is coupled to said microwave resonator.

Abstract: A three-dimensional superconducting qubit and a method for manufacturing the same are disclosed. In an example, a three-dimensional superconducting qubit comprises a structural base comprising one or more insulating materials, and superconductive patterns on surfaces of the structural base. The superconductive patterns form at least a capacitive part and an inductive part of the three-dimensional superconducting qubit. A first surface of the surfaces of the structural base defines a first plane and a second surface of the surfaces of the structural base defines a second plane, the second plane being oriented differently than the first plane. At least one superconductive pattern of the superconductive patterns extends from the first surface to the second surface.

Abstract: A method, system, and arrangement for resetting qubits are disclosed. An example system includes one or more quantum circuit refrigerators for resetting qubits. Each of the quantum circuit refrigerators includes a tunneling junction and a control input for receiving a control signal. Photon-assisted single-electron tunneling takes place across the respective tunneling junction in response to a control signal. Capacitive or inductive coupling elements between the qubits and the quantum circuit refrigerators couple each qubit to the quantum circuit refrigerator(s). The qubits, quantum circuit refrigerators, and coupling elements are located in a cryogenically cooled environment. A common control signal line to the control inputs crosses into the cryogenically cooled environment from a room temperature environment.

Abstract: For reading out a state of a qubit, a readout input waveform is injected into a system that comprises an information storage element for storing the state of the qubit and a readout resonator that is electromagnetically coupled to said information storage element. A readout output waveform is extracted from said system and detected. The injection of the readout input waveform takes place through an excitation port that is also used to inject excitation waveforms to the information storage element for affecting the state of the qubit. A phase of the readout input waveform is controllably shifted in the course of injecting it into the system.