Ghost D-branes Research Articles

Classical Solution for Ghost D-Branes in String Field Theory

Ghost D-branes have been proposed as objects that cancel the effects of D-branes. We construct a classical solution which represents an arbitrary number of D-branes and ghost D-branes in the context of open string field theory. Cancellation of BRST cohomology between D-branes and ghost D-branes is shown.

Constraints on a class of classical solutions in open string field theory

We calculate boundary states for general string fields in the KBc subalgebra under some regularity conditions based on the construction by Kiermaier, Okawa, and Zwiebach. The resulting boundary states are always proportional to that for the perturbative vacuum |B>. In this framework, the equation of motion implies that boundary states are independent of the auxiliary parameter s associated with the length of the boundary. By requiring the s-independence, we show that the boundary states for classical solutions in our class are restricted to \pm|B> and 0. In particular, there exist no string fields which reproduce boundary states for multiple D-brane backgrounds. While we know that the boundary states |B> and 0 are reproduced by solutions for the perturbative vacuum and the tachyon vacuum, respectively, no solutions reproducing -|B> have been constructed. In this paper we also propose a candidate for such a solution, which may describe the ghost D-brane.

Quintessence and phantom dark energy from ghostD-branes

We present a novel dark-energy candidate, based upon the existence and dynamics of ghost D-branes in a warped compactification of type IIB string theory. Gp-branes cancel the combined BPS sectors of the Dp-branes, while they preserve the same supersymmetries. We show that this scenario can naturally lead to either quintessence or phantomlike behaviors, depending on the form of the involved potentials and brane tension. As a specific example we investigate the static, dark-energy dominated solution subclass.

D-BRANES AND CLOSED STRING FIELD THEORY

We construct solitonic states in the OSp invariant string field theory, which are BRST invariant in the leading order of regularization parameter. One can show that these solitonic states describe D-branes and ghost D-branes, by calculating the scattering amplitudes.

D-brane states and disk amplitudes inOSpinvariant closed string field theory

We construct solitonic states in the OSp invariant string field theory, which are BRST invariant in the leading order of regularization parameter $\epsilon$. We calculate the disk amplitudes using these solitonic states and show that they describe D-branes and ghost D-branes.

Ghost D-brane, supersymmetry and matrix model

In this note we study the world volume theory of pairs of D-brane and ghost D-brane, which is shown to have 16 linear supersymmetries and 16 nonlinear supersymmetries. In particular we study a matrix model based on the pairs of D(-1)-brane and ghost D(-1)-brane. Since such pairs are supposed to be equivalent to the closed string vacuum, we expect all 32 supersymmetries should be unbroken. We show that the world volume theory of the pairs of D-brane and ghost D-brane has unbroken 32 supersymmetries even though a half of them are nonlinearly realized.

D-branes and closed string field theory

We construct BRST invariant solitonic states in the OSp invariant string field theory for closed bosonic strings. Our construction is a generalization of the one given in the noncritical case. These states are made by using the boundary states for D-branes, and can be regarded as states in which D-branes or ghost D-branes are excited. We calculate the vacuum amplitude in the presence of solitons perturbatively and show that the cylinder amplitude for the D-brane is reproduced. The results imply that these are states with even number of D-branes or ghost D-branes.

Ghost D-branes

We define a ghost D-brane in superstring theories as an object that cancels the effects of an ordinary D-brane. The supergroups U(N|M) and OSp(N|M) arise as gauge symmetries in the supersymmetric world-volume theory of D-branes and ghost D-branes. A system with a pair of D-brane and ghost D-brane located at the same location is physically equivalent to the closed string vacuum. When they are separated, the system becomes a new brane configuration. We generalize the type I/heterotic duality by including n ghost D9-branes on the type I side and by considering the heterotic string whose gauge group is OSp(32+2n|2n). Motivated by the type IIB S-duality applied to D9- and ghost D9-branes, we also find type II-like closed superstrings with U(n|n) gauge symmetry.

Gauge invariant regularization in the AdS/CFT correspondence and ghost D-branes

A field theoretic understanding of how the radial direction in the AdS/CFT correspondence plays the role of a gauge invariant measure of energy scale has long been missing. In SU(N) Yang–Mills, a realization of a gauge invariant cutoff has been achieved by embedding the theory in spontaneously broken SU(N|N) gauge theory. With the recent discovery of ghost D-branes an AdS/CFT correspondence version of this scheme is now possible. We show that a very simple construction precisely ties the two pictures together providing a concrete understanding of the radial RG flow on the field theory side.