Theoretical basis of SQUID-based artificial neurons

The physical basis of an artificial neuron is studied using a model that is based on the stochastic transition between two states in a double well potential. It is shown that the stochastic transition model generates an energy-defined sigmoid function acting as an activation (or transfer) function in neurons. The model is also applied to circuit neurons using superconducting quantum interference devices in artificial neural networks.PACS numbers: 87.19.ll, 85.25.Dq, 07.05.Mh.This work is supported in part by MEXT (17K05579)

The effect of dissipation on quantum transmission resonance

Quantum transmissions of a free particle passing through a rectangular potential barrier with dissipation are studied using a path decomposition technique. Dissipative processes strongly suppress the transmission probability at resonance just above the barrier resulting in an unexpected reduction of the mean traversal time through the potential barrier.Comment: 8 pages, 5 figures, Accepted for publication in Physics Letters

Topologically Linked Crystals

We discovered a new class of topological crystals, namely linked rings of crystals. Two rings of tantalum triselenide (TaSe3) single crystals were linked to each other while crystal growing. The topology of the crystal form is called a "Hopf link", which is the simplest link involving just two component unknots linked together exactly once. The feature of the crystals is not covered by the conventional crystallography.Comment: 6 pages, 3 figures, to appear in J. Crystal Growt

Josephson Effect between Condensates with Different Internal Structures

A general formula for Josephson current in a wide class of hybrid junctions between different internal structures is derived on the basis of the Andreev picture. The formula extends existing formulae and also enables us to analyze novel B-phase/A-phase/B-phase (BAB) junctions in superfluid helium three systems, which are accessible to experiments. It is predicted that BAB junctions will exhibit two types of current-phase relations associated with different internal symmetries. A ``pseudo-magnetic interface effect'' inherent in the system is also revealed.Comment: 4 pages, 2 figure