The D-instanton and other supersymmetric D-branes in IIB plane-wave string theory

TL;DR

This paper explores a class of supersymmetric D-branes in type IIB plane-wave string theory, analyzing their construction, supersymmetry properties, and equivalence of open and closed string descriptions, including a classical view of the D-instanton.

Contribution

It introduces new supersymmetric D-branes with massless world-volume fermions and demonstrates their construction via boundary states and open string quantization, establishing their properties and dual descriptions.

Findings

Constructed various supersymmetric D-branes preserving half the dynamical supersymmetries.

Evaluated cylinder diagrams and demonstrated equivalence of open and closed string descriptions.

Provided a classical analysis of the D-instanton in light-cone gauge.

Abstract

A class of D-branes for the type IIB plane-wave background is considered that preserve half the dynamical supersymmetries of the light-cone gauge. The D-branes of this type are the euclidean (or instantonic) (0,0), (0,4) and (4,0) branes (where (r,s) denotes a brane oriented with r axes in the first four directions transverse to the +,- light-cone and s axes in the second four directions). Corresponding lorentzian D-branes are (+,-;0,0), (+,-;0,4) and (+,-;4,0). These are constructed in two ways. The first uses a boundary state formalism which implements appropriate fermionic gluing conditions and the second is based on a direct quantisation of the open strings ending on the branes. In distinction to the D-branes considered earlier these have massless world-volume fermions but do not possess kinematical supersymmetries. Cylinder diagrams describing the overlap between a pair of boundary states displaced by some distance are evaluated. The open-string description of this system involves mode frequencies that are, in general, given by irrational solutions to transcendental equations. The closed-string and open-string descriptions are shown to be equivalent by a nontrivial implementation of the S modular transformation. A classical description of the D-instanton (the (0,0) case) in light-cone gauge is also given.