The effects of spacetime quantization on black hole and big bang/big crunch singularities can be studied using new tools from (2+1)dimensional quantum gravity. I investigate effects of spacetime quantization on singularities of the (2+1)-dimensional BTZ black hole and the (2+1)-dimensional torus universe. Hosoya has considered the BTZ black hole, and using a “quantum generalized affine paramete...

We construct an effective action for gravity in which all homogeneous solutions are nonsingular1). In particular, there is neither a big bang nor a big crunch. The action is a higher derivative modification of Einstein’s theory constructed in analogy to how the action for point particle motion of particles in special relativity is obtained from Newtonian mechanics. ⋆ Invited talk at Internation...

We compute correlation functions of closed strings in Misner space, a big crunch big bang universe. We develop a general method for correlators with twist fields, which are relevant for the investigation on the condensation of winding tachyon. We propose to compute the correlation functions by performing an analytic continuation of the results in C/ZN Euclidean orbifold. In particular, we obtai...

The supersymmetric (AdS3×S)/ZN orbifold constructed by the authors in hep-th/0106171 is shown to describe AdS fragmentation, where fivebranes are emerging from the F1-NS5 background. The twisted sector moduli of the orbifold are the collective coordinates of groups of n5/N fivebranes. We discuss the relation between the descriptions of this background as a perturbative string orbifold and as a ...

We consider string theory in a time dependent orbifold with a null singularity. The singularity separates a contracting universe from an expanding universe, thus constituting a big crunch followed by a big bang. We quantize the theory both in light-cone gauge and covariantly. We also compute some tree and one loop amplitudes which exhibit interesting behavior near the singularity. Our results a...

In this paper, two universal reinforcement learning methods are considered to solve the problem of maximum power point tracking for photovoltaics. Both exhibit fast achievement MPP under varying environmental conditions and applicable in different PV systems. The only required knowledge system open-circuit voltage, short-circuit current power, all STC, which always provided by manufacturer. com...

The generalized Szekeres family of solution for quasi-spherical space-time of higher dimensions are obtained in the scalar tensor theory of gravitation. Brans-Dicke field equations expressed in Dicke’s revised units are exhaustively solved for all the subfamilies of the said family. A particular group of solutions may also be interpreted as due to the presence of the so-called C-field of Hoyle ...