Many photonic crystal (PhC) devices are non-periodic structures due to the introduced defects in an otherwise perfectly periodic PhC, and they are often connected by PhC waveguides that serve as input and output ports. Numerical simulation of a PhC device requires boundary conditions to terminate PhC waveguides that extend to infinity. The rigorous boundary condition for terminating a PhC waveg...

The 80 years since Zachariasen’s famous paper, 20 years before Stephen Elliott was born, on the random network theory of glass structure have seen remarkable progress in our understanding of the structure of glassy materials through the construction of models and comparison with experiment. In the early days, models were hand-built with plastic units and had free boundary conditions. Today, ver...

We calculate radiative corrections to the Casimir effect for the massive complex scalar field with the λφ4 self-interaction in d + 1 dimensions. We consider the field submitted to four types of boundary conditions on two parallel planes, namely: (i) quasi-periodic boundary conditions, which interpolates continuously periodic and anti-periodic ones, (ii) Dirichlet conditions on both planes, (iii...

The classical problem of heat conduction in one dimension on a composite ring is examined. The problem is formulated using the heat equation with periodic boundary conditions. We provide an explicit solution of this problem using the Method of Fokas. The location of the interfaces is known, but neither temperature nor heat flux are prescribed there. Instead, the physical assumption of continuit...

It is proved that the scattering amplitude known at a fixed frequency, a fixed direction of the incident plane wave and all directions of the scattered wave in a solid angle, however small, determine uniquely the shape of a strictly convex obstacle with a smooth but not analytic boundary on which the Dirichlet boundary condition is assumed.

Numerical minimization of the euclidean action of the two-dimensional abelian Higgs model is used to construct periodic instantons, the euclidean field configurations with two turning points describing transitions between the vicinities of topologically distinct vacua. Periodic instantons are found at any energy (up to the sphaleron energy Esp h ) and for a wide range of parameters of the theor...

This paper considers numerical methods for stability analyses of periodic solutions of ordinary differential equations. Stability of a periodic solution can be determined by the corresponding monodromy matrix and its eigenvalues. Some commonly used numerical methods can produce inaccurate results of them in some cases, for example, near bifurcation points or when one of the eigenvalues is very ...

The famous question called the ergodic hypothesis suggested that for a typical Hamiltonian on a typical energy surface all, but a set of zero measure of initial conditions, have trajectories covering densely this energy surface itself. However, KAM theory showed that for nearly integrable systems there is a set of initial conditions of positive measure of quasi periodic trajectories. This dispr...