Search results for "classical"

Effects of the Surface and Finite Temperature on the Electronic Structure of Metal Clusters

1996

The most fascinating feature of simple metal clusters is the existence of the electronic shell structure. This was observed first in alkali[1] and noble metals[2] and later also in some other nontransition metals[3,4,5]. The shell structure is a consequence of nearly free valence electrons confined to a finite volume. A spherical potential will always lead to a shell structure, the origin of which is the orbital angular momentum l and the large degeneracy (2l+1) associated with it. However, this primitive shell structure is strengthened by ’accidental’ degeneracies between states having different principal quantum numbers. Thus the shell structure of a hydrogen atom is different from that o…

Anharmonic elasticity theory for sound attenuation in disordered solids with fluctuating elastic constants

2010

Configuration Expansion by Means of Pseudonatural Orbitals

1977

The configuration interaction (CI) method as a general approach to solving the many-electron Schrodinger equation to—in principle—any desired accuracy, has been described in this volume by Shavitt. We refer to that chapter for all basic concepts of the CI method and an outline of its merits and its computational problems.

Organization of Quantum Bifurcations: Crossover of Rovibrational Bands in Spherical Top Molecules

1989

Qualitative changes in the rotational structure of a finite particle quantum system are studied. The crossover phenomenon is explained from the point of view of consecutive quantum bifurcations. The generic organization of bifurcations is related to the stratification of the space of dynamical variables imposed by the invariance group of the Hamiltonian.

Quantum Einstein Gravity: Towards an Asymptotically Safe Field Theory of Gravity

2007

VORTEX LAYERS IN THE SMALL VISCOSITY LIMIT

2006

In this paper we suppose that the initial datum for the 2D Navier–Stokes equations are of the vortex layer type, in the sense that there is a rapid variation in the tangential component across a curve. The variation occurs through a distance which is of the same order of the square root of the viscosity. Assuming the initial as well the matching (with the outer flow) data analytic, we show that our model equations are well posed. Another necessary assumption is that the radius of curvature of the curve is much larger than the thickness of the layer.

Theory and modeling of polarization switching in ferroelectrics

2005

Abstract Kinetics of polarization response in ferroelectrics is reproduced within Langevin, Fokker–Planck and imaginary time Schrodinger equation techniques for energy functionals of growing complexity modeling an assembly of coarse grained particles with attractive first neighbor interaction. Symplectic integration based numerical approach captures dynamic hysteresis, polarization switching, and spatially extended stationary polarization. Solution of relevant nonstationary problem is adapted to large scale parallel computing.

A new approach to interacting fields

1974

A model for a description of interaction, which involves particle creation, can be given as follows: (1) A smooth finite-dimensional manifoldM constitutes the configuration space of some interacting system. (2) The concept of an interacting field is formulated in terms of two-component objects which consist of a physical and a topological field component which are ‘derived’ fromM. (3) Interaction is described in terms of the topological linking number of the topological field components and in terms of the intrinsic field equations.

Heat transfer in conducting and radiating bodies

1997

Abstract We introduce briefly some nonlocal models for heat transfer in conducting and radiating media. The goal is to give an idea of the general mathematical structure and related existence results for such models.

Maxwell Theory as a Classical FieldTheory

2012

Hamilton’s variational principle and the Lagrangian mechanics that rests on it are exceedingly successful in their application to mechanical systems with a finite number of degrees of freedom. Hamilton’s principle characterizes the physically realizable orbits, among the set of all possible orbits, as being the critical elements of the action integral. The Lagrangian function, although not an observable on its own, is not only useful in deriving the equations of motion but is also an important tool for identifying symmetries of the theory and constructing the corresponding conserved quantities, via Noether’s theorem.