Related papers: Closed string field theory without the level-match…

We offer some thoughts regarding the space of string fields. We suggest that this space should be identified as the odd component of a star-algebra and focus among other issues on the role of the mid-point. We argue that theories with…

This is an introduction to two-dimensional conformal field theory and its applications in string theory. Modern concepts of conformal field theory are explained, and it is outlined how they are used in recent studies of D-branes in the…

In our continued efforts of matching full string computations with the corresponding effective field theory computations, we evaluate string theory correlators in closed forms. In particular, we consider a correlator between three SYM…

We revisit the non-linear sigma model approach to string theory with the closed superstring field theory. We construct the string field theory around the non-linear sigma model background with the patch-by-patch description. We show that…

We study covariant open bosonic string field theory in lightcone gauge. When lightcone gauge is well-defined, we find two results. First, the vertices of the gauge-fixed action consist of Mandelstam diagrams with stubs covering specific…

We prove local background independence of the complete quantum closed string field theory using the recursion relations for string vertices and the existence of connections in CFT theory space. Indeed, with this data we construct an…

We construct a class of quadratic gauge invariant actions for extended string fields defined on the tensor product of open superstring state space for multiple open string Neveu-Schwarz (NS) sectors with or without one Ramond (R) sector.…

We study the level-expansion structure of the NS string field theory actions, mainly focusing on the modified (i.e. 0-picture in the NS sector) cubic superstring field theory. This theory has a non-trivial structure already at the quadratic…

Couplings between a closed string RR field and open strings are calculated in a system of coincident branes and antibranes of type II theory. The result can be written cleanly using the curvature of the superconnection.

We use the level truncation scheme to obtain accurate descriptions of open bosonic string field configurations corresponding to large marginal deformations such as background Wilson lines. To do so, we solve for all fields as functions of…

We study noncommutativity in open strings using the covariant phase space formalism. For tensile open strings in a constant Kalb-Ramond background, we show that the (pre)-symplectic current splits into a bulk kinetic term plus an exact…

Motivated by noncommutative Chern-Simons theory, we construct an infinite class of field theories that satisfy the axioms of Witten's string field theory. These constructions have no propagating open string degrees of freedom. We…

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…

We prove that the finite gauge transformation of the Ramond sector of the modified cubic superstring field theory is ill-defined due to collisions of picture changing operators. Despite this problem we study to what extent could a bijective…

We examine the symmetries of the action suppelemented by the constraint in the WZW-type open superstring field theory. It is found that this pseudo-action has additional symmetries provided we impose the constraint after the transformation.…

We construct the symplectic form on the covariant phase space of the open string field theory on a ZZ-brane in c=1 string theory, and determine the energy of the rolling tachyon solution, confirming Sen's earlier proposal based on boundary…

We study open and closed string interactions in the Type IIB plane wave background using open+closed string field theory. We reproduce all string amplitudes from the dual N=2 Sp(N) gauge theory by computing matrix elements of the dilatation…

We revisit the existence, background independence and uniqueness of closed, open and open-closed bosonic- and topological string field theory, using the machinery of homotopy algebra. In a theory of classical open- and closed strings, the…

The boundary conditions of the bosonic string theory in non-zero $B$-field background are equivalent to the second class constraints of a discretized version of the theory. By projecting the original canonical coordinates onto the…

We revisit the construction of the tensionless limit of closed bosonic string theory in the covariant formulation in the light of Galilean conformal symmetry that rises as the residual gauge symmetry on the tensionless worldsheet. We relate…