It is expected that the state of an atom or molecule, initially put into an excited state with an energy below the ionization threshold, relaxes to a groundstate by spontaneous emission of photons which propagate to spatial infinity. In this paper, this picture is established for a large class of models of non-relativistic atoms and molecules coupled to the quantized radiation field, but with t...

We prove the existence of time-periodic and spatially localized oscillations (discrete breathers) in a class of planar Euclidean-invariant Hamiltonian systems consisting of a finite number of interacting particles. This result is obtained in an “anticontinuous” limit, where atomic masses split into two groups that have different orders of magnitude (the mass ratio tending to infinity) and sever...

We propose relativistic second quantization of matrix model of D particles in a general framework of nonlocal field theory based on Snyder-Yang’s quantized space-time. Second-quantized nonlocal field is in general noncommutative with quantized space-time, but conjectured to become commutative with light cone time X+. This conjecture enables us to find second-quantized Hamiltonian of D particle ...

Motivated by recent experimental works, we investigate a system of vortex dynamics in an atomic Bose-Einstein condensate (BEC), consisting of three vortices, two of which have the same charge. These vortices are modeled as a system of point particles which possesses a Hamiltonian structure. This tripole system constitutes a prototypical model of vortices in BECs exhibiting chaos. By using the a...

A multiscale approach was adopted for the calculation of confined states in self-assembled semiconductor quantum dots (QDs). While results close to experimental data have been obtained with a combination of atomistic strain and tight-binding (TB) electronic structure description for the confined quantum states in the QD, the TB calculation requires substantial computational resources. To allevi...

Effective nuclear charges of the main group elements from the second up to the fifth row have been developed for the one-electron part of the spin-orbit (SO) coupling Hamiltonian. These parameters, suitable to be used for SO calculations of large molecular systems, provide a useful and remarkably good approximation to the full SO Hamiltonian. We have derived atomic effective nuclear charges by ...

Starting from a general Hamiltonian of pair-coupled anharmonic (quartic) oscillators, together with the concept of local normal coordinates, a unified model description of both order-disorder and displacive types of SPT-systems is proposed. Within the framework of the standard variational procedure, a hybridized pseudospin-phonon Hamiltonian is formulated by introducing variables corresponding ...

We examine the role of electronic relaxation in the description of K-K charge transfer for ion-atom collisions with bare or one-electron projectiles in the intermediate velocity region. Total and differential K-K transfer cross sections for the system F9+ +Si are calculated within the coupled-state impact parameter method, starting from a relaxed molecular Hamiltonian and from a frozen two-cent...

Interaction of a two-level atom with a single mode of electromagnetic field including Kerr nonlinearity for the field and intensity-dependent atom-field coupling is discussed. The Hamiltonian for the atom-field system is written in terms of the elements of a closed algebra, which has SU(1,1) and Heisenberg-Weyl algebras as limiting cases. Eigenstates and eigenvalues of the Hamiltonian are const...