Related papers: Effective String Theory of Dual Superconductivity
A fundamental task for the heterotic superstring theory is the determination of the effective action describing the physics of massless string excitations at low energies. This is necessary for the phenomenological applications of string…
In this paper, which is a revised version of the author's PhD thesis, we analyze two different applications of string theory. In the first part, we focus on four dimensional compactifications of Type II string theories preserving N=1…
We consider a conformal system of a string and a particle defined in D=10+2 space-time dimensions. The extra time-like dimension is a gauge artifact and can be eliminated by choosing a gauge in which the SO(10,1) Lorentz symmetry is…
We present superconducting vortex solutions in the two-Higgs doublet model which has a gauged $U(1)$ Higgs-family symmetry. We write down an ansatz for the solution and study its basic properties, for the case of both global and gauged…
We study the interaction of several types of static straight cosmic strings, including local strings, global strings, and bosonic superconducting strings with and without magnetic currents. First, we evaluate the interaction energy of two…
In this paper we investigate the possibility whether, in the extreme limit of high energies and large transverse distances, reggeon field theory might serve as an effective theory of high energy scattering for strong interactions. We…
Stable ring solutions supported by the angular momentum caused by superconducting charge and current have been suggested to exist in the gauged $U(1)\times U(1)$ field theory. We construct potentially cosmologically relevant solutions using…
We study the high-energy limit of $2 \to 2$ one-loop string amplitudes at fixed momentum transfer. For the closed string, the high-energy behaviour of the amplitudes can be determined from Regge theory just like in field theory, as was…
We derive an optical theorem for perturbative CFTs which computes the double discontinuity of conformal correlators from the single discontinuities of lower order correlators, in analogy with the optical theorem for flat space scattering…
Strong - weak coupling duality in string theory allows us to compute physical quantities both at the weak coupling end and at the strong coupling end. Furthermore perturbative string theory can be used to compute corrections to the leading…
Semiclassical spinning string states in AdS_5 are, in general, characterised by the three SO(2,4) conserved charges: the energy E and the two spins S_1 and S_2. We discuss several examples of explicit classical solutions for rigid closed…
A quantum perfect lattice action in four dimensions can be derived analytically as a renormalized trajectory when we perform a block spin transformation of monopole currents in a simple but non-trivial case of quadratic monopole…
Ideas presented in two earlier papers are applied to string theory. It had been found that a deterministic cellular automaton in one space- and one time dimension can be mapped onto a bosonic quantum field theory on a 1+1 dimensional…
An example of a consistent theory with massive higher spin fields is constructed in flat space-time of dimension three. The action is written in the light-cone gauge. The theory has certain stringy features, e.g. its spectrum is unbounded…
We study the decay of high spin mesons using the gauge/string theory correspondence. The rate of the process is calculated by studying the splitting of a macroscopic string intersecting a D-brane. The result is applied to the decay of…
We study the low-energy dynamics of semi-classical vortex strings living above Argyres-Douglas superconformal field theories. The worldsheet theory of the string is shown to be a deformation of the CP^N model which flows in the infra-red to…
We discuss AdS/CFT duality in the sector of ``semiclassical'' string states with large quantum numbers. We review the coherent-state effective action approach, in which similar 2d sigma model actions appear from the AdS_5 x S^5 string…
We probe the effective worldvolume theory of a set of coinciding D-branes by switching on constant electro-magnetic fields on them. The comparison of the mass spectrum predicted by string theory with the mass spectrum obtained from the…
We review two-dimensional QCD. The report contains: 1. Introduction. 2. QCD$_2$ as a field theory 2.1 The 1/N expansion and spectrum, 2.2 Ambiguity in the self-energy of the quark, 2.3 Polyakov--Wiegmann formula and gauge interactions, 2.4…
A world-sheet sigma model approach is applied to string theories dual to four-dimensional gauge theories, and semi-classical soliton solutions representing highly excited string states are identified which correspond to gauge theory…