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P. Forgács

Publications and source records attributed to P. Forgács.

8 recordsLinked to original sources

Comment on "Finite Size Corrections to the Radiation Reaction Force in Classical Electrodynamics" [arXiv:1005.2617]

In [1, arXiv:1005.2617] effective field theory methods have been employed to compute the equations of motion of a spherically symmetric charged shell of radius R, taking into account the radiation reaction force exerted by the shell's own electromagnetic field up to O(R^2). The authors of Ref. [1] have stated that the known result for the self force of the shell as can be found from Eq. (16.28) of the textbook of Jackson [2] (see also Chap. 4 in the review of Pearle [3]) is incorrect, in that the term linear in R should be absent. We claim that this conclusion of Ref. [1] is incorrect, and that the textbook result, Eq. (1) does hold.

gr-qc

Numerical and asymptotic analysis of the 't Hooft-Polyakov magnetic monopole

A high precision numerical analysis of the static, spherically symmetric SU(2) magnetic monopole equations is carried out. Using multi-shooting and multi-domain spectral methods, the mass of the monopole is obtained rather precisely as a function of $β=M_H/M_W$ for a large $β$-interval ($M_H$ and $M_W$ denote the mass of the Higgs and gauge field respectively). The numerical results necessitated the reexamination and subsequent correction of a previous asymptotic analysis of the monopole mass in the literature for $β\ll1$.

hep-th

Static Cosmological Solutions of the Einstein-Yang-Mills-Higgs Equations

Numerical evidence is presented for the existence of a new family of static, globally regular `cosmological' solutions of the spherically symmetric Einstein-Yang-Mills-Higgs equations. These solutions are characterized by two natural numbers ($m\geq 1$, $n\geq 0$), the number of nodes of the Yang-Mills and Higgs field respectively. The corresponding spacetimes are static with spatially compact sections with 3-sphere topology.

gr-qc

Quantum equivalence of sigma models related by non Abelian Duality Transformations

Coupling constant renormalization is investigated in 2 dimensional sigma models related by non Abelian duality transformations. In this respect it is shown that in the one loop order of perturbation theory the duals of a one parameter family of models, interpolating between the SU(2) principal model and the O(3) sigma model, exhibit the same behaviour as the original models. For the O(3) model also the two loop equivalence is investigated, and is found to be broken just like in the already known example of the principal model.

hep-th

Quantum corrections of Abelian Duality Transformations

A modification of the Abelian Duality transformations is proposed guaranteeing that a (not necessarily conformally invariant) $σ$-model be quantum equivalent (at least up to two loops in perturbation theory) to its dual. This requires a somewhat non standard perturbative treatment of the {\sl dual} $σ$-model. Explicit formulae of the modified duality transformation are presented for a special class of block diagonal purely metric $σ$-models.

hep-th

Perturbative Quantum (In)equivalence of Dual $σ$ Models in $2$ dimensions

Various examples of target space duality transformations are investigated up to two loop order in perturbation theory. Our results show that when using the tree level (`naive') transformation rules the dual theories are in general {\it inequivalent} at two loops to the original ones, (both for the Abelian and the non Abelian duality).

hep-th