We study a new type of Josephson device, the so-called “optical Josephson junction” as proposed in Phys. Rev. Lett. 95, 170402 (2005). Two condensates are optically coupled through a waveguide by a pair of Bragg beams. This optical Josephson junction is analogous to the usual Josephson junction of two condensates weakly coupled via tunneling. We discuss the use of this optical Josephson junctio...

A systematic theoretical-approach has been made to estimate various parameters, characteristics and their optimization methods for a Josephson junction to be useful as a high-speed switching element in Josephson digital logic electronics. The dynamic response of Josephson junction has been obtained using computer simulation. Our concept of turn-on deay of Josephson junction is applied in order ...

The current-phase (I-φ) relation of a double-barrier Josephson junction with a two-gap superconductor as intermediate electrode is derived by means of a simplified version of Ohta’s model. As in conventional double-barrier Josephson junctions, a marked skewness in the I-φ curves is present. Moreover, as in heterotic Josephson devices, a reduction of the maximum Josephson current is predicted. A...

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...

The Josephson tunnel junction is the basic element of a superconducting quantum interference device (SQUID). Amongst other parameters, the junction capacitance determines the characteristics of a (digital) SQUID. In a conventional dc SQUID, reducing the junction capacitance decreases the flux noise of the sensor, whereas in digital SQUIDs, the operating frequency can be increased when reducing ...

The Josephson current of spin-entangled electrons through the two branches of a SQUID-like structure with two quantum dots exhibits a magnetic-flux response different from the conventional Josephson current. Because of their interference, the period of maximum Josephson current changes from h/2e to h/e, which can be used for detecting the Cooper-pair splitting efficiency. The nonlocal spin enta...

We show that the quantum properties of some Josephson SQUID devices are described by a boundary sine Gordon model. Our approach naturally describes multi-junction SQUID devices and, when applied to a single junction SQUID (the rf-SQUID), it reproduces the known results of Glazman and Hekking. We provide a detailed analysis of the regimes accessible to an rf-SQUID and to a two-Josephson junction...

A new analysis of heavy-ion collision experiments uncovers evidence that two colliding nuclei behave like a Josephson junction—a device in which Cooper pairs tunnel through barrier between superfluids.