arXiv subjects

Kamal Lochan Panigrahi

Publications and source records attributed to Kamal Lochan Panigrahi.

4 recordsLinked to original sources

arXiv2004

D-Branes and Noncommutative String Theory

In this thesis we discuss some nonperturbative and noncommutative aspects of string theory. We present low-energy background field solutions corresponding to various D-branes (and their bound states) and intersecting branes in flat and pp-wave spacetime. A class of D-brane bound states are constructed from charged macroscopic strings and they are shown to satisfy the mass-charge relationship of 1/2 BPS bound states. Another class of D-branes and intersecting branes are constructed, by solving the type II field equations explicitly, in pp-wave background with constant and non-constant flux. The worldsheet construction of these D-branes and their spacetime supersymmetry properties have also been analyzed in some detail. Further, we study an example of open strings ending on D-branes with mixed boundary condition. In this context, we analyze various open and mixed sector tree-level amplitudes of N=2 strings in the presence of constant NS-NS antisymmetric tensor (B) field.

hep-th↗

arXiv2002

Intersecting Membranes from Charged Macroscopic Strings

We present a class of orthogonal membrane configurations which preserve 1/4 of the full type IIA supersymmetry. These membrane configurations carry additional F-string charges. We further analyze the D1-D3 configuration after applying T- duality along the world volume directions of the above orthogonal membranes.

hep-th↗

arXiv2002

Bound States of String Networks and D-branes

We show the existence of non-threshold bound states of (p, q) string networks and D3-branes, preserving 1/4 of the full type IIB supersymmetry, interpreted as string networks dissolved in D3-branes. We also write down the expression for the mass density of the system and discuss the extension of the construction to other Dp-branes. Differences in our construction of string networks with the ones interpreted as dyons in N=4 gauge theories are also pointed out.

hep-th↗

arXiv2001

Noncommutative N=2 Strings

We analyze open and mixed sector tree-level amplitudes of N=2 strings in a space-time with (2,2) signature, in the presence of constant B field. The expected topological nature of string amplitudes in the open sector is shown to impose nontrivial constraints on the corresponding noncommutative field theory. In the mixed sector, we first compute a 3-point function and show that the corresponding field theory is written in terms of a generalized *-product. We also analyze a 4-point function (A_{oooc}) of the mixed sector in Theta ---> infinity limit.

hep-th↗