On the D(–1)/D7-brane systems (original) (raw)

The field theory of non-supersymmetric brane configurations

Nuclear Physics B, 1998

We identify the 4D field theories living on the world volume of D4 branes in nonsupersymmetric type IIA string theory constructions. They are softly broken N=2 SQCD with the breakings introduced through vevs of the auxilliary fields in the spurion coupling field. Exact solutions of these theories for perturbing soft breakings exist in the literature. We calculate the ratios of string tensions in softly broken N=2 SU(N) gauge theory testing the recently proposed M-theory prediction. The semi-classical result of M-theory is renormalized in the non-supersymmetric models.

Branes and six-dimensional supersymmetric theories

We consider configurations of six-branes, five-branes and eight-branes in various superstring backgrounds. These configurations give rise to (0, 1) supersymmetric theories in six dimensions. The condition for RR charge conservation of a brane configuration translates to the condition that the corresponding field theory is anomaly-free. Sets of infinitely many models with non-trivial RG fixed points at strong coupling are demonstrated. Some of them reproduce and generalise the world-volume theories of SO(32) and E 8 × E 8 small instantons. All the models are shown to be connected by smooth transitions. In particular, the small instanton transition for which a tensor multiplet is traded for 29 hypermultiplets is explicitly demonstrated. The particular limit in which these theories can be considered as six-dimensional string theories without gravity are discussed. New fixed points (string theories) associated with E n global symmetries are discovered by taking the strong string coupling limit.

D-branes in non-critical superstrings and duality in Script N = 1 gauge theories with flavor

Journal of High Energy Physics, 2006

We study D-branes in the superstring background IR 3,1 × SL(2, IR) k=1 /U (1) which are extended in the cigar direction. Some of these branes are new. The branes realize flavor in the four dimensional N = 1 gauge theories on the D-branes localized at the tip of the cigar. We study the analytic properties of the boundary conformal field theories on these branes with respect to their defining parameter and find non-trivial monodromies in this parameter. Through this approach, we gain a better understanding of the brane set-ups in ten dimensions involving wrapped NS5-branes. As one application, using the boundary conformal field theory description of the electric and magnetic D-branes, we can understand electric-magnetic (Seiberg) duality in N = 1 SQCD microscopically in a string theoretic context. P 2 , and vanishes at P 2 = 0. For other values of (J, M ), the corresponding boundary states set down in were studied in detail in . One aspect which was not very clear about these branes was whether they have a well-defined unitary self-overlap. 3 . We find here that one can indeed understand these branes systematically following the ideas of and there do exist branes with a unitary spectrum for values of J in the range 0 ≤ J ≤ 1 2 . These branes have a semiclassical interpretation of turning on a worldvolume two form flux in the region near the tip of the cigar. At J = 0, this value of the flux reaches a critical value and localizes at the tip, corresponding to forming a localized brane. In the quantum theory, this is seen in a relation between the boundary states which expresses the localized identity boundary state as a difference between the J = M = 0 and the 1 The branes which are Dirichlet in some of the flat directions are also interesting, they give rise to non-perturbative effects like domain walls and instantons [8] in the gauge theories. 2 These are similar to the ZZ [14] and FZZT [15,16] branes in Liouville theory; in fact the relation between them is more than an analogy [17]. 3 It was noticed [18] that for real values of J ∈ ( 1 4 , 1 2 ], the self-overlaps are well-defined.

Euclidean D-branes and higher-dimensional gauge theory

Nuclear Physics B, 1998

We consider euclidean D-branes wrapping around manifolds of exceptional holonomy in dimensions seven and eight. The resulting theory on the D-brane-that is, the dimensional reduction of 10-dimensional supersymmetric Yang-Mills theoryis a cohomological field theory which describes the topology of the moduli space of instantons. The 7-dimensional theory is an N T =2 (or balanced) cohomological theory given by an action potential of Chern-Simons type. As a by-product of this method, we construct a related cohomological field theory which describes the monopole moduli space on a 7-manifold of G 2 holonomy.

Gauge Theories from D Branes

Frontiers in Number Theory, Physics, and Geometry II

In these lectures we start with a pedagogical introduction of the properties of open and closed superstrings and then, using the open/closed string duality, we construct the boundary state that provides the description of the maximally supersymmetric Dp branes in terms of the perturbative string formalism. We then use it for deriving the corresponding supergravity solution and the Born-Infeld action and for studying the properties of the maximally supersymmetric gauge theories living on their worldvolume. In the last section of these lectures we extend these results to less supersymmetric and non-conformal gauge theories by considering fractional branes of orbifolds and wrapped branes. Lectures given at the School "Frontiers in Number Theory, Physics and Geometry", Les Houches, March 2003.

N =1/2 gauge theory and its instanton moduli space from open strings in R-R background

Journal of High Energy Physics, 2004

We derive the four dimensional N = 1/2 super Yang-Mills theory from tree-level computations in RNS open string theory with insertions of closed string Ramond-Ramond vertices. We also study instanton configurations in this gauge theory and their ADHM moduli space, using systems of D3 and D(-1) branes in a R-R background.

Flux interactions on D-branes and instantons

Journal of High Energy Physics, 2008

We provide a direct world-sheet derivation of the couplings of NS-NS and R-R fluxes to various types of D-branes (including instantonic ones) by evaluating disk amplitudes among two open string vertex operators at a generic brane intersection and one closed string vertex representing the background fluxes. This world-sheet approach is in full agreement with the derivation of the flux couplings in the brane effective actions based on supergravity methods, but it is applicable also to more general brane configurations involving fields with twisted boundary conditions. As an application, we consider an orbifold compactification of Type IIB string theory with fractional D-branes preserving N = 1 supersymmetry and study the flux-induced fermionic mass terms both on space-filling branes and on instantonic ones. Our results show the existence of a relation between the soft supersymmetry breaking and the lifting of some instanton fermionic zero-modes, which may lead to new types of non-perturbative couplings in brane-world models.

Brane Profiles of Non-Supersymmetric Strings

JHEP 09 (2024) 019, 2024

We connect the indications of 2D CFT for branes in non-supersymmetric strings to actual spacetime profiles, taking the bulk tadpole potentials into account. We find exact solutions for the uncharged branes that spread in the internal intervals of Dudas-Mourad vacua for non-tachyonic orientifolds and heterotic strings. These solutions involve suitable dressings of the uncharged branes of the nine-dimensional tadpole-free theory. Similar exact results for uncharged branes that are transverse to the internal space, or for charged branes, appear more challenging. Nevertheless, we identify their large-distance behavior, which is determined by linearized equations, and show that it is compatible with the CFT analysis in all expected cases. We also provide some hints on the leading back-reaction of the form-fields.

Universality in all-order α' corrections to BPS/non-BPS brane world volume theories

2012

Knowledge of all-α' higher derivative corrections to leading order BPS and non-BPS brane actions would serve in future endeavor of determining the complete form of the non-abelian BPS and tachyonic effective actions. In this paper, we note that there is a universality in the all-α' order corrections to BPS and non-BPS branes. We compute amplitudes between one Ramond-Ramond C-field vertex operator and several SYM gauge/scalar vertex operators. Specifically, we evaluate in closed form string correlators of two-point amplitudes A^Cϕ, A^CA, a three-point amplitude A^Cϕϕ and a four-point amplitude A^Cϕϕϕ. We carry out pole and contact term analysis. In particular we reproduce some of the contact terms and the infinite massless poles of A^Cϕϕϕ by SYM vertices obtained through the universality.

D-branes in little string theory

Nuclear Physics B, 2005

We analyze in detail the D-branes in the near-horizon limit of NS5-branes on a circle, the holographic dual of little string theory in a double scaling limit. We emphasize their geometry in the background of the NS5-branes and show the relation with D-branes in coset models. The exact one-point functions giving the coupling of the closed string states with the D-branes and the spectrum of open strings are computed.