The Ising spin model in multiple helices with hierarchically organized interactions is investigated using Monte Carlo simulations. The numerical result of specific heat shows that the Curie temperature of the ferromagnetic transition is strongly dependent on to what extent the basal helix is...

The nature of correlated electrons confined in two dimensions is analyzed using the spectral statistics of three electrons confined in a square-well quantum dot. When in a small quantum dot, the spectral statistics of electrons are similar to those of Poisson distribution. As the quantum dot...

The travelling salesman problem, in which the best route between cities to be visited is chosen from a large number of possible routes, is reconsidered using the time reversal of physical dynamics, e.g. an inverse of the diffusion process. Information mediators assigned to every city diffuse as...

A material-designing principle in which a hierarchical structure is achieved by a series of steps of folding a low-order structure into a high-order structure is introduced in comparison with periodic arrays of unit cells. Multiply looped rings are a typical example, in which a ring consists of...

Electronic structures in a hierarchical helix with inter-round couplings, i.e., a multiply twisted helix, are investigated using the spectral statistics of a quantum particle. The hierarchical structure is constructed using a procedure in which a helical chain of components is twisted, producing...