相关论文: Minimal strings and Semiclassical Expansion

Any candidate theory of quantum gravity must address the breakdown of the classical smooth manifold picture of space-time at distances comparable to the Planck length. String theory, in contrast, is formulated on conventional space-time.…

The near horizon geometry of a fundamental string wrapped around an S1 reduced to four dimensions is expected to be AdS2 x S2. A probe string analysis suggests a no-force condition indicating supersymmetry, which coincides with the…

The Cremmer-Scherk mechanism is generalised in a non-Abelian context. In the presence of the Higgs scalars of the standard model it is argued that fields arising from the low energy effective string action may contribute to the mass…

Positive frequency Wightman function, vacuum expectation values of the field square and the energy-momentum tensor induced by a Z_{2}-symmetric brane with finite thickness located on (D+1)- dimensional AdS background are evaluated for a…

Branes are ubiquitous elements of any low-energy limit of string theory. We point out that negative tension branes violate all the standard energy conditions of the higher-dimensional spacetime they are embedded in; this opens the door to…

A simple real-space model for the free-electron wavefunction with spin is proposed, based on coherent vortices on the scale of h/mc, rotating at mc^2/h. This reproduces the proper values for electron spin and magnetic moment. Transformation…

A new approach to composite superconformal strings is considered . This composite string model has two scales: first one (~1 Gev) is for edging surfaces and second one (Planck scale) is for ridge surfaces . Nonlinear realization of…

The single harmonic oscillator and double-well potentials are important systems in quantum mechanics. The single harmonic oscillator is {\it the} paradigm in physics, and is taught in nearly all beginner undergraduate classes, while the…

Four-dimensional strings with the standard model gauge group $SU(3)\times SU(2)\times U(1)$ give model-dependent predictions for the tree level weak mixing-angle. In the presence of an extra pseudo-anomalous gauged- ${U(1)}_X$, the value of…

We describe a mean field technique for quantum string (or dimer) models. Unlike traditional mean field approaches, the method is general enough to include string condensed phases in addition to the usual symmetry breaking phases. Thus, it…

We describe the minimal configurations of the compact D=11 Supermembrane and D-branes when the spatial part of the world-volume is a K\"ahler manifold. The minima of the corresponding hamiltonians arise at immersions into the target space…

String theory is the leading contemporary framework to explore the synthesis of quantum mechanics with gravity. String phenomenology aims to study string theory while maintaining contact with observational data. The fermionic $Z_2\times…

Misner space, also known as the Lorentzian orbifold $R^{1,1}/boost$, is the simplest tree-level solution of string theory with a cosmological singularity. We compute tree-level scattering amplitudes involving twisted states, using operator…

In string theory, an important challenge is to show if the singularity of black holes can be smoothed out by the complete $\alpha^{\prime}$ corrections. The simplest case is to consider a 2D string black hole or 3D black string. This…

The (q_1,q_2) SL(2,Z) string bound states of type IIB superstring theory admit two inequivalent (T-dual) representations in eleven dimensions in terms of a fundamental 2-brane. In both cases, the spectrum of membrane oscillations can be…

We investigate the inclusion of 10-dimensional string loop corrections to the entropy function of two-charge extremal small black holes of the heterotic string theory compactified on S^1 x T^5 and show that the entropy is given by…

BRST quantization is carried out for a model of p-branes with second class constraints. After extension of the phase space the constraint algebra coincides with the one of null string when p=1. It is shown that in this case one can or can…

We show how the Szekeres form of the line element is naturally adapted to study Penrose limits in classical string backgrounds. Relating the "old" colliding wave problem to the Penrose limiting procedure as employed in string theory we…

We investigate quantum corrections to the classical four-dimensional low-energy effective action of type II string theory compactified on SU(3) structure geometries. Various methods previously developed for Calabi-Yau compactifications are…

We investigate the low energy physics implications of a prototype quasi-realistic superstring model with an anomalous U(1). First, we present the techniques utilized to compute the mass spectrum and superpotential couplings at the string…