Casimir interaction of finite-width strings

Within the trln-formalism we investigate the vacuum interaction of cosmic strings and the influence of strings width on this effect. For the massless real scalar field we compute the Casimir contribution into the total vacuum energy. The dimensional-regularization technique is used. It is shown that the regularized Casimir term contains neither the UV-divergences, nor the divergences related with the non-integrability of the renormalized vacuum mean of the energy-momentum tensor.Comment: 3 figure

Chiral String in a Curved Space: Gravitational Self-Action

We analyze the effective action describing the linearised gravitational self-action for a classical superconducting string in a curved spacetime. It is shown that the divergent part of the effective action is equal to zero for the both Nambu-Goto and chiral superconducting string.Comment: 5 pages, LaTe

Vacuum polarization near cosmic string in RS2 brane world

Gravitational field of cosmic strings in theories with extra spatial dimensions must differ significantly from that in the Einstein's theory. This means that all gravity induced properties of cosmic strings need to be revised too. Here we consider the effect of vacuum polarization outside a straight infinitely thin cosmic string embedded in a RS2 brane world. Perturbation technique combined with the method of dimensional regularization is used to calculate ${}_{vac}^{ren}$ for a massless scalar field.Comment: 8 pages, RevTeX

Self-forces in the Spacetime of Multiple Cosmic Strings

We calculate the electromagnetic self-force on a stationary linear distribution of four-current in the spacetime of multiple cosmic strings. It is shown that if the current is infinitely thin and stretched along a line which is parallel to the strings the problem admits an explicit solution.Comment: This paper has been produced in Latex format and has 18 page

Self-Interactions in the Spacetime of a Scalar-Tensor Cosmic String

We study the effect of the geometry and topology of a scalar-tensor cosmic string space-time on the electric and magnetic fields of line sources. It is shown that the dilatonic coupling of the gravity induces effects along the string comparable to a current flow allowing for forbidden regions near the string.Comment: 7 pages, 2 figures. Revised version to appear in the Phys. Lett.

On the quantum dynamics of a point particle in conical space

A quantum neutral particle, constrained to move on a conical surface, is used as a toy model to explore bound states due to both a inverse squared distance potential and a $\delta$-function potential, which appear naturally in the model. These pathological potentials are treated with the self-adjoint extension method which yields the correct boundary condition (not necessarily a null wavefunction) at the origin. We show that the usual boundary condition requiring that the wavefunction vanishes at the origin is arbitrary and drastically reduces the number of bound states if used. The situation studied here is closely related to the problem of a dipole moving in conical space.Comment: To appear in Annals of Physic

NON-LOCAL EFFECTS IN THEORY OF GRAVITATIONAL INTERACTION

There the topological effects which originate in interaction between the classic and quantized fields and particles and the gravitational field are studied. The study method of interaction of gravitational waves with the statistic systems has been offered. The effect of combination attenuation of gravitational wave has been detected. The non-local radiation effects in the system of cosmic strings have been considered for the first time. The effect of conical Cherenkov's radiation has been detected. The method which allowed to describe the classic and quantized topological effects by the multiconical spaces has been offered. The effect of Kazimirov's interaction of two point gravitating particles in 2+1 theory of graviation has been detectedAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Vacuum polarization and classical self-action near higher-dimensional defects

We analyze the gravity-induced effects associated with a massless scalar field in a higher-dimensional spacetime being the tensor product of $$(d-n)$$-dimensional Minkowski space and n-dimensional spherically/cylindrically symmetric space with a solid/planar angle deficit. These spacetimes are considered as simple models for a multidimensional global monopole (if $$n\geqslant 3$$) or cosmic string (if $$n=2$$) with $$(d-n-1)$$ flat extra dimensions. Thus, we refer to them as conical backgrounds. In terms of the angular-deficit value, we derive the perturbative expression for the scalar Green function, valid for any $$d\geqslant 3$$ and $$2\leqslant n\leqslant d-1$$, and compute it to the leading order. With the use of this Green function we compute the renormalized vacuum expectation value of the field square $${\langle \phi ^{{}2}(x)\rangle }_{\mathrm{ren}}$$ and the renormalized vacuum averaged of the scalar-field energy-momentum tensor $${\langle T_{M N}(x)\rangle }_{\mathrm{ren}}$$ for arbitrary d and n from the interval mentioned above and arbitrary coupling constant to the curvature $$\xi$$. In particular, we revisit the computation of the vacuum polarization effects for a non-minimally coupled massless scalar field in the spacetime of a straight cosmic string. The same Green function enables to consider the old purely classical problem of the gravity-induced self-action of a classical point-like scalar or electric charge, placed at rest at some fixed point of the space under consideration. To deal with divergences, which appear in consideration of the two problems, we apply the dimensional-regularization technique, widely used in quantum field theory. The explicit dependence of the results upon the dimensionalities of both the bulk and conical submanifold is discussed