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36
Dbranes, tachyons, and string field theory
, 2003
"... In these notes we provide a pedagogical introduction to the subject of tachyon condensation in Witten’s cubic bosonic open string field theory. We use both the lowenergy YangMills description and the language of string field theory to explain the problem of tachyon condensation on unstable Dbra ..."
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Cited by 76 (4 self)
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In these notes we provide a pedagogical introduction to the subject of tachyon condensation in Witten’s cubic bosonic open string field theory. We use both the lowenergy YangMills description and the language of string field theory to explain the problem of tachyon condensation on unstable Dbranes. We give a selfcontained introduction to open string field theory using both conformal field theory and overlap integrals. Our main subjects are the Sen conjectures on tachyon condensation in open string field theory and the evidence that supports these conjectures. We conclude with a discussion of vacuum string field theory and projectors of the staralgebra of open string fields. We comment on the possible role of string field theory in the construction of a nonperturbative formulation of string theory that captures all possible string backgrounds.
A worldvolume perspective on the recombination of intersecting branes
 JHEP
"... Abstract: We study brane recombination for supersymmetric configurations of intersecting branes in terms of the worldvolume field theory. This field theory contains an impurity, corresponding to the degrees of freedom localized at the intersection. The Higgs branch, on which the impurity fields con ..."
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Cited by 15 (0 self)
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Abstract: We study brane recombination for supersymmetric configurations of intersecting branes in terms of the worldvolume field theory. This field theory contains an impurity, corresponding to the degrees of freedom localized at the intersection. The Higgs branch, on which the impurity fields condense, consists of vacua for which the intersection is deformed into a smooth calibrated manifold. We show this explicitly using a superspace formalism for which the calibration equations arise naturally from F and Dflatness. Keywords: Dbranes, Supersymmetric effective theories, brane dynamics in gauge theories, tachyon condensation. – 1 – Contents
Adding a brane to the brane antibrane action
 in BSFT,” JHEP 0310, 002
, 2003
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Spectral flow and boundary string field theory for angled dbranes
 JHEP
"... Abstract: Dbranes intersecting at an arbitrary fixed angle generically constitute a configuration unstable towards recombination. The reconnection of the branes nucleates at the intersection point and involves a generalization of the process of brane decay of interest to nonperturbative string dyn ..."
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Cited by 10 (1 self)
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Abstract: Dbranes intersecting at an arbitrary fixed angle generically constitute a configuration unstable towards recombination. The reconnection of the branes nucleates at the intersection point and involves a generalization of the process of brane decay of interest to nonperturbative string dynamics as well as cosmology. After reviewing the string spectrum of systems of angled branes, we show that worldsheet twist superfields may be used in the context of Boundary Superstring Field Theory to describe the dynamics. Changing the angle between the branes is seen from the worldsheet as spectral flow with boundary insertions flowing from bosonic to fermionic operators. We calculate the complete tachyon potential and the low energy effective action as a function of angle and find an expression that interpolates between the braneantibrane and the DiracBornInfeld actions. The potential captures the mechanism of Dbrane recombination and provides for interesting new
Slowly varying tachyon and tachyon potential
 JHEP 0305 (2003) 058 [arXiv:hepth/0304145
"... We show that the scattering amplitude of four open string scalars or tachyons on the worldvolume of a Dpbrane in the bosonic string theory can be written in a universal form. The difference between this amplitude and the corresponding amplitude in the superstring theory is in an extra tachyonic po ..."
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Cited by 9 (0 self)
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We show that the scattering amplitude of four open string scalars or tachyons on the worldvolume of a Dpbrane in the bosonic string theory can be written in a universal form. The difference between this amplitude and the corresponding amplitude in the superstring theory is in an extra tachyonic pole. We show that in an α ′ expansion and for slowly varying fields, the amplitude is consistent with the tachyonic DBI action in which the tachyon potential is V (T) = e−(√πT/α) 2 with α = 1 for bosonic theory and α = √ 2 for Decay of unstable branes is an interesting process which might shed some new light in understanding properties of string theory in timedependent backgrounds [1][15]. In particular, it was pointed out by Sen that an effective action of the BornInfeld type proposed in [16, 17, 18] can capture many properties of these decaying processes [3]. This action for
N=1 Locally Supersymmetric Standard Models from Intersecting Branes”, hepth/0309070, Revised version
"... We construct four dimensional intersecting D6brane models that have locally the spectrum of the N=1 Supersymmetric Standard Model. All open visible string sectors share the same N=1 supersymmetry. As expected in these supersymmetric classes of models, where the D6branes wrap a toroidal orientifold ..."
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Cited by 8 (5 self)
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We construct four dimensional intersecting D6brane models that have locally the spectrum of the N=1 Supersymmetric Standard Model. All open visible string sectors share the same N=1 supersymmetry. As expected in these supersymmetric classes of models, where the D6branes wrap a toroidal orientifold of type IIA, the hierarchy may be stabilized if the string scale is low, e.g. below 30 TeV. We analyze the breaking of supersymmetry in the vicinity of the supersymmetric point by turning on complex structure deformations as FayetIliopoulos terms. Positive masses for all squarks and sleptons, to avoid charge/colour breaking minima, may be reached when also two loop contributions may be included. In the ultimate version of the present models N=1 supersymmetry may be broken by gauge mediation. The constructions with four, five and six stacks of D6branes at Ms are build directly. Next by the use of brane recombination we are able to show that there is a continuous, RR homology flow, between six, five and four stack models. Moreover, we examine the gauge coupling constants of the
A Quantum Analysis on Recombination Process and Dynamics of Dpbranes at one angle”, [arXiv:hepth/0304237
"... A quantummechanical technique is used within the framework of U(2) superYangMills theory to describe recombination processes of two Dpbranes at one angle; how tachyons condense starting from certain initial conditions, and how (curved) shapes of the recombined branes develop. Two types of initi ..."
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A quantummechanical technique is used within the framework of U(2) superYangMills theory to describe recombination processes of two Dpbranes at one angle; how tachyons condense starting from certain initial conditions, and how (curved) shapes of the recombined branes develop. Two types of initial conditions are considered: branes at one angle made put from parallel ones at the initial moment, and the ones approaching each other slowly, which is important as a candidate of inflation mechanism. An interesting behavior of the branes ’ shapes is shown to appear, each of which comes to have multiple (three) extremes due to localization of tachyon condensation but not the effect of compact spaces. Blowingup behavior of paircreations of stings connecting the recombined branes are also observed. The above two behaviors means that the branes in the process have a relatively stronger tendency than naively expected, to dissipate their energy into radiations of gravitational and (RR and NSNS) gauge fields. This implies that the tachyonic preheating era might be rather short if this setup is applied to the braneworld scenarios.
Higher dimensional recombination of intersecting Dbranes
 JHEP
, 2004
"... We study recombination of Dbranes system intersecting at more than one angle using super YangMills theory. We find the condensation of an offdiagonal tachyon mode relates to the recombination, as was clarified in branes at one angle in hepth/0303204. In branes at two angles, after the tachyon mo ..."
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We study recombination of Dbranes system intersecting at more than one angle using super YangMills theory. We find the condensation of an offdiagonal tachyon mode relates to the recombination, as was clarified in branes at one angle in hepth/0303204. In branes at two angles, after the tachyon mode between two D2branes condensed, D2brane charge distributes in the bulk near an intersection point. We also find that when two intersection angles are equal, the offdiagonal lowest mode becomes massless, and a new stable nonabelian configuration, which is supersymmetric up to a quadratic order in the fluctuation, is found by the deformation by this mode.
Condensation of Tubular D2branes in Magnetic Field Background
, 2004
"... It is known that in the Minkowski vacuum a bunch of IIA superstrings with D0branes can be blownup to a supersymmetric tubular D2brane, which is supported against collapse by the angular momentum generated by crossed electric and magnetic BornInfeld (BI) fields. In this paper we show how the mult ..."
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Cited by 3 (1 self)
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It is known that in the Minkowski vacuum a bunch of IIA superstrings with D0branes can be blownup to a supersymmetric tubular D2brane, which is supported against collapse by the angular momentum generated by crossed electric and magnetic BornInfeld (BI) fields. In this paper we show how the multiple, smaller tubes with relative angular momentum could condense to a single, larger tube to stabilize the system. Such a phenomena could also be shown in the systems under the Melvin magnetic tube or uniform magnetic field background. However, depending on the magnitude of field strength, a tube in the uniform magnetic field background may split into multiple, smaller tubes with relative angular momentum to stabilize the system.