Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · hep-th/0408073

A Geometric Interpretation of the Open String Tachyon

D. Kutasov
View original source ↗Read source document ↗Export metadata ↓

Abstract

Unstable, non-BPS D-branes in weakly coupled ten dimensional string theory have many mysterious properties. Among other things, it is not clear what sets their tension, what is their relation to the better understood BPS D-branes, and why the open string tachyon on them is described by an effective Lagrangian which suggests that the tachyon corresponds to an extra spatial dimension transverse to the branes. We point out that the dynamics of D-branes in the presence of Neveu-Schwarz fivebranes on a transverse R^3 times S^1 provides a useful toy model for studying these issues. From the point of view of a 5+1 dimensional observer living on the fivebranes, BPS D-branes in ten dimensions give rise to two kinds of D-branes, which are BPS or non-BPS depending on whether they do or do not wrap the S^1. Their tensions are related, since from a higher dimensional perspective, they are the same objects. D-branes localized on the S^1 have a tachyon corresponding to their position on the circle. This field is described by the same Lagrangian as that of a tachyon on a non-BPS D-brane in ten dimensions. Its geometrical interpretation is useful for clarifying the properties of non-BPS branes in six dimensions. If the lessons from the six dimensional system can be applied in ten dimensions, the existence of non-BPS D-branes seems to suggest the presence of at least one extra dimension in critical type II string theory.

Explore related subjects

hep-th

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

D. Kutasov. 2004-08-10. A Geometric Interpretation of the Open String Tachyon. https://arxiv.org/abs/hep-th/0408073

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Six Easy Pieces: interplays among dualities in 4d, 3d and 2d

In this paper we consider 4d $\mathcal{N}=1$ $\mathrm{SU}(N)$ gauge theories with $N+1$ fundamentals, five antifundamentals and a conjugate two index antisymmetric tensor. The model has been shown to be in a mixed phase in the IR, splitting in an interacting non-Abelian Coulomb phase and a free magnetic phase. Through tensor deconfinement, we show that baryonic deformations lead to a non-Abelian free magnetic phase. Along the analysis we obtain a duality with symplectic SQCD that can be further reduced to 3d and 2d. In the 3d case the analysis of the three sphere partition function allows one to obtain dualities between $\mathrm{SU}(N)$ with a two index symmetric tensor and $\mathrm{SO}(N)$ theories. On the other hand, in 2d we recover dualities already known in the literature and propose new ones between special unitary and symplectic gauge theories.

hep-th↗
arXiv2026

Flat holography for spinor fields

We extend the hyperbolic Milne-slicing construction of flat holography in four-dimensional Minkowski spacetime from scalar fields to massless spin-$\frac{1}{2}$ fields. We solve the massive mode equation and restrict the boundary source-response analysis to the massless sector. Decomposition into harmonics on three-dimensional hyperbolic space, labeled by a continuous principal-series parameter, yields a separated-point nonlocal kernel up to the action normalization and local contact terms. The kernel has the universal form required by two-dimensional conformal covariance for spin-$\frac{1}{2}$ principal-series primaries. Then we construct regular source-normalized conformal-primary wavefunctions in planar and global coordinates on the celestial sphere $S^2$. We show that the planar source-response kernel is naturally identified with the spin-$\frac{1}{2}$ shadow transform, while inverse shadowing recovers the angular delta-function structure of the unshadowed basis. We also analyze radial renormalization by analytic continuation from the principal-series problem to a real-mass AdS$_3$ problem.

hep-th↗
arXiv2026

Off-shell recursion for all-loop planar integrands in Yang-Mills theory

In this paper, we develop in detail the off-shell recursion for planar loop integrands in Yang-Mills theory. Starting from the classical equations of motion solved with the perturbiner method, we derive an exact transfer-matrix representation of the pure-gluon sector. We then include the ghost contributions to the loop kernels based on \cite{Tao:2025fch}. Finally, as an example, we work out the two-loop recursion in detail and conclude a general recursion strategy for two-loop planar integrands whose external legs are gluons.

hep-th↗