Chiral Magnetic Josephson Junction as a Base for Low-Noise Superconducting Qubits

Low temperature decoherence and relaxation in charge Josephson junction qubits

Vibrating superconducting island in a Josephson junction.

We consider a combined nanomechanical-supercondcuting device that allows the Cooper pair tunneling to interfere with the mechanical motion of the middle superconducting island. Coupling of mechanical oscillations of a superconducting island between two superconducting leads to the electronic tunneling generates a supercurrent that is modulated by the oscillatory motion of the island. This coupl...

Spectroscopy of capacitively coupled Josephson-junction qubits

We show that two capacitively coupled Josephson junctions, in the quantum limit, form a simple coupled qubit system with effective coupling controlled by the junction bias currents. We compute numerically the energy levels and wave functions for the system, and show how these may be tuned to make optimal qubits. The dependence of the energy levels on the parameters can be measured spectroscopic...

Josephson-Junction Qubits: Entanglement and Coherence

Since our previous article, " Quantum Computing with rf SQUIDs " , which appeared about four years ago in The Photon, we have made changes in our primary approach to the use of superconducting elements as qubits. Now we are focusing on single Josephson junctions as qubits, an idea that was suggested by members of our research group. 1 The qubit (quantum bit) of a quantum computer differs from t...

Josephson Junction Materials Research Using Phase Qubits

At present, the performance of superconducting qubits is limited by decoherence. Strong decoherence of phase qubits is associated with spurious microwave resonators residing within the Josephson junction tunnel barrier [1]. In this work, we investigate three different fabrication techniques for producing tunnel junctions that vary the properties of the superconductor-insulator interface. Throug...