121217873
On the calculation of the interquark potential generated by a string with massive ends
The variational equations, defining the stationary point of the effective action of the Nambu-Goto string with massive ends, are solved numerically by making use of an iterative procedure. The obtained solution enables one to evaluate the string functional integral. Proceeding from this, the interquark potential generated by a string with massive ends is derived. Calculations show that the higher iterative corrections turn out to be small, and the zero approximation fairly well reproduces the interquark potential generated by the Nambu-Goto string with massive ends. {copyright} {ital 1997} {ital The American Physical Society}
118320834
Surface modes and photonic modes in Casimir calculations for a compact cylinder
A rigorous formulation of the problem of calculating the electromagnetic vacuum energy of an infinite dielectric cylinder is discussed. It is shown that the physically relevant spectrum of electromagnetic excitations includes the surface modes and photonic modes. The mathematical procedure of summing over this spectrum is proposed, and the transition to imaginary frequencies is accomplished. As a result, the imaginary-frequency representation for the vacuum energy is justified which has been used in previous Casimir studies for this configuration.
29489956
Direct mode summation for the Casimir energy of a solid ball
The Casimir energy of a solid ball placed in an infinite medium is calculated by a direct frequency summation using the contour integration. It is assumed that the permittivity and permeability of the ball and medium satisfy the condition . After deriving the general expression for the Casimir energy, a compact ball is considered when . Calculations are carried out which are of the first order in and take account of the fifth-order terms in the uniform asymptotic expansion of the Bessel functions involved. The implication of the results to attempt to explain sonoluminescence via the Casimir effect is briefly discussed.
126085042
ON THE INTERPRETATION OF THE NOETHER IDENTITIES
121905919
Eikonal approximation for high-energy inclusive processes
15884859
Casimir energy of a nonuniform string
The Casimir energy of a non-uniform string built up from two pieces with different speed of sound is calculated. A standard procedure of subtracting the energy of an infinite uniform string is applied, the subtraction being interpreted as the renormalization of the string tension. It is shown that in the case of a homogeneous string this method is completely equivalent to the zeta renormalization.
118213659
Pion form factor in a scalar model
SummaryUsing as an example the simple scalar modelρ(6)3; we describe our method of analysing the bound-state form factors based on the systematic use of the alpha-representation for Feynman diagrams. The nature of «nonrenormalization group» logarithms specific for the form-factor-type problems is investigated. The summation of ladder contributions is performed in the leading-logarithm approximation.RiassuntoUsando come esempio il semplice modello scalareρ(6)3 si descrive il metodo di analizzare i fattori di forma dello stato legato basati sull’uso sistematico della rappresentazione alfa per i diagrammi di Feyman. Si studia la natura dei logaritmi del gruppo di non rinormalizzazione specifico di problemi di tipo fattore di forma. Si esegue la somma dei contributi di a gradini nell’approssimazione del logaritmo principale.РезюмеНа примере простой скалярной моделиρ(6)3 излагается метод анализа формфакторов составных систем, основанный на систематическом использовании альфа-представления фейнмановских диаграмм. Исследуется природа «неренормгрупповых» логарифмов, специфичных для задач формфакторного типа. Проведено суммирование лестничных вкладов в главном лограрифмическом приближении.
125654630
Pion Form-factor and {QCD} Sum Rules
118802177
Vibrating potential model for giant resonances in deformed metal clusters and atomic nuclei
The vibrating potential model is extended to provide a description of giant resonances in metal clusters and atomic nuclei with any kind of deformation.
121516467
CollectiveEλ excitations of surface character in spherical and deformed sodium clusters: vibrating potential model
The self-consistent vibrating potential model (VPM) is extended for the description ofEλ surface collective excitations in alkali metal clusters with practically any kind of static deformation. The case of spherical clusters is also covered. Any single-particle potentials and valence electron densities for which the coefficients of the multipole expansion are known can be used within the model. The strength function method incorporated into the model allows one to avoid solving the equations for every state and, as a result, simplifies the calculations drastically. The model is of a quite general character and can also be used for description of giant resonances in atomic nuclei if the Coulomb terms are neglected. The VPM is applied to calculate theE1,E2 andE3 excitations in spherical (Na8, Na20 and Na40) and deformed (Na10, Na18 and Na26) clusters.
123206973
The interior of the charge transition density and the structure of low-lying states in deformed nuclei
The RPA calculations of charge transition densities (CTD) rho lambda mu nu (r) for the E2 transitions from the ground state to the low-lying Ipi Knu =2+2nu and 2+0nu states in 164Dy predict rather strong peaks of single-particle nature in the interior of the CTD. A simple explanation of the results is given. The reliability of the results obtained, their possible application to the study of the structure of low-lying states and some predictions for nuclei of the rare-earth region are discussed.