Superconducting pi qubit with a ferromagnetic Josephson junction.

Josephson Current in a Ferromagnetic Semiconductor/Semiconductor/Ferromagnetic Semiconductor Junction with Superconducting Contacts

Theoretical proposal for superconducting spin qubits

We propose and theoretically investigate superconducting spin qubits. Superconducting spin qubit consists of a single spin confined in a Josephson junction. We show that owing to spin-orbit interaction, superconducting phase difference across the junction can polarize this spin. We demonstrate that this enables single-qubit operations and more complicated quantum gates, where spins of different...

Coupling of two superconductors through a ferromagnet: evidence for a pi junction.

We report measurements of the temperature dependence of the critical current, I(c), in Josephson junctions consisting of conventional superconducting banks of Nb and a weakly ferromagnetic interlayer of a CuxNi1-x alloy, with x around 0.5. With decreasing temperature I(c) generally increases, but for specific thicknesses of the ferromagnetic interlayer, a maximum is found followed by a strong d...

Fabrication and measurement of a niobium persistent current qubit

Recent successes with superconducting Josephson junction qubits make them prime candidates for the implementation of quantum computing. This doctoral thesis details the study of a niobium Josephson junction circuit for quantum computing applications. The thesis covers two main areas: 1) the fabrication of sub-micron niobium Josephson junction devices using a Nb/Al/AlO./Nb trilayer process and 2...

Resonant readout of a superconducting persistent current qubit

Superconducting Josephson junction devices rank among the best candidates for realizing a quantum computer. While the coherent control of quantum dynamics has been demonstrated in these solid-state, macroscopic quantum systems, a major challenge has been to increase the coherence times for these qubits. With an objective to reduce the level of readout-induced decoherence, this thesis work focus...