We discuss an experiment in which two magnetic insulators that both show a field-induced magnetic ordering transition are weakly coupled to one another and are placed into an external magnetic field. If the respective magnetic states can be interpreted as phase-coherent Bose–Einstein condensates of magnetic bosonic quasiparticles, one expects the occurrence of Josephson effects. For two identic...

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 interplay between superconductivity and Coulomb interactions has been studied for more than 20 years now1–13. In low-dimensional systems, superconductivity degrades in the presence of Coulomb repulsion: interactions tend to suppress fluctuations of charge, thereby increasing fluctuations of phase. This can lead to the occurrence of a superconducting– insulator transition, as has been observ...

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...

We study a phase dynamics induced by a spin dynamics in a ferromagnetic Josephson junction, in which two superconductors (SC’s) are separated by a ferromagnetic layer. A new phenomenological model for the phase variable is proposed by including the spin dynamics excited by the ferromagnetic resonance (FMR) in the gauge invariant phase of s-wave SC’s. We found that the current-voltage characteri...

We discuss and review the basic physics that leads to superfluidity/superconductivity in certain quantum Hall states, in particular the so-called double-layered (mmm) state. In the K-matrix description of the quantum correlation in quantum Hall states, those states with det(K) = 0 contain a special correlation that leads to superfluidity/superconductivity. We propose a four-terminal measurement...

The dc Josephson effect refers to the dissipationless electrical current – the supercurrent – that can be sustained across a weak link connecting two bulk superconductors.1 This effect is a probe of the fundamental nature of the superconducting state, which depends crucially on the spatial dimensionality of the superconducting electrodes. For bulk (i.e. threedimensional) superconductors, the su...