We present different techniques to numerically solve the equations of motion for the widely studied Discrete Nonlinear Schrödinger equation (DNLS). Being a Hamiltonian system, the DNLS requires symplectic routines for an efficient numerical treatment. Here, we introduce different such schemes in detail and compare their performance and accuracy by extensive numerical simulations.

Many inverse problems for differential equations can be formulated as optimal control problems. It is well known that inverse problems often need to be regularized to obtain good approximations. This work presents a systematic method to regularize and to establish error estimates for approximations to some control problems in high dimension, based on symplectic approximation of the Hamiltonian ...

In this article we consider the problem of finding Hamiltonian cycles on a tetrahedral mesh. A Hamiltonian cycle is a closed loop through a tetrahedral mesh that visits each tetrahedron exactly once. Using techniques of a novel discrete differential geometry of n-simplices, we could immediately obtain Hamiltonian cycles on a rhombic dodecahedronshaped tetrahedral mesh consisting of 24 tetrahedr...

The Hamiltonian system related to discrete-time cheap linear quadratic Riccati (LQR) problems is analyzed in a purely geometric context, with the twofold purpose of getting a useful insight into its structural features and deriving a numerically implementable solution for the infinite-horizon case by only using the standard geometric approach routines available.

We have studied the discrete nonlinear Schrödinger equation (DNLSE) with on-site defects and periodic boundary conditions. When the array dynamics becomes chaotic, the otherwise quasiperiodic amplitude correlations between the oscillators are destroyed via a symmetry breaking instability. However, we show that synchronization of symbolic information of suitable amplitude signals is possible in ...

Revivals of the coherent states of a deformed, adiabatically and cyclically varying oscillator Hamiltonian are examined. The revival time distribution is exactly that of Poincaré recurrences for a rotation map: only three distinct revival times can occur, with specified weights. A link is thus established between quantum revivals and recurrences in a coarse-grained discrete-time dynamical system.

Using two methods we show that a quantized discrete breather in a 1D lattice is stable. One method uses path integrals and compares correlations for a (linear) local mode with those of the quantum breather. The other takes a local mode as the zeroth order system relative to which numerical, cutoff-insensitive diagonalization of the Hamiltonian is performed.

We study discrete surface breathers in two-dimensional lattices of inductively coupled split-ring resonators with capacitive nonlinearity. We consider both conservative (Hamiltonian) and analyze the properties of the modes localized in space and periodic in time (discrete breathers) located in the corners and on the edges of the lattice. We find that surface breathers in the Hamiltonian systems...

Fractional Fourier Transform, which is a generalization of the classical Fourier Transform, is a powerful tool for the analysis of transient signals. The discrete Fractional Fourier Transform Hamiltonians have been proposed in the past with varying degrees of correlation between their eigenvectors and Hermite Gaussian functions. In this paper, we propose a new Hamiltonian for the discrete Fract...

This paper aims to develop a linearly implicit structure-preserving numerical scheme for the space fractional sine-Gordon equation, which is based on newly developed invariant energy quadratization method. First, we reformulate equation as canonical Hamiltonian system by virtue of variational derivative functional with Laplacian. Then, utilize centered difference formula discrete equivalent der...