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176
Closed String Tachyon Condensation: An Overview
, 2005
"... These notes are an expanded version of a review lecture on closed string tachyon condensation at the RTN workshop in Copenhagen in September 2003. We begin with a lightning review of open string tachyon condensation, and then proceed to review recent results on localized closed string tachyon conden ..."
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Cited by 59 (6 self)
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These notes are an expanded version of a review lecture on closed string tachyon condensation at the RTN workshop in Copenhagen in September 2003. We begin with a lightning review of open string tachyon condensation, and then proceed to review recent results on localized closed string tachyon condensation, focusing on two simple systems, C/Zn orbifolds and twisted circle compactifications.
Tduality and actions for nonBPS Dbranes
 JHEP 0005
"... We employ Tduality to restrict the tachyon dependence of effective actions for nonBPS Dbranes. For the BornInfeld part the criteria of Tduality and supersymmetry Dpbranes [1] have played a crucial rule in the understanding of the relations between different string theories. They are stable ext ..."
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Cited by 53 (0 self)
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We employ Tduality to restrict the tachyon dependence of effective actions for nonBPS Dbranes. For the BornInfeld part the criteria of Tduality and supersymmetry Dpbranes [1] have played a crucial rule in the understanding of the relations between different string theories. They are stable extended objects, which preserve half of the maximal supersymmetry. They are known in terms of explicit solutions to lowenergy supergravity equations, and their effective actions and its symmetries are by now well
On the validity of the solution of string field theory
 JHEP 0605
"... Abstract: We analyze the realm of validity of the recently found tachyon solution of cubic string field theory. We find that the equation of motion holds in a non trivial way when this solution is contracted with itself. This calculation is needed to conclude the proof of Sen’s first conjecture. We ..."
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Cited by 53 (14 self)
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Abstract: We analyze the realm of validity of the recently found tachyon solution of cubic string field theory. We find that the equation of motion holds in a non trivial way when this solution is contracted with itself. This calculation is needed to conclude the proof of Sen’s first conjecture. We also find that the equation of motion holds when the tachyon or
1+1 dimensional NCOS and its U(N) gauge theory dual,” Int
 J. Mod. Phys. A
"... We study some aspects of open string theories on Dbranes with critical electric fields. We show that the massless open string modes that move in the direction of the electric field decouple. In the 1+1 dimensional case the dual theory is U(N) SYM with electric flux, and the decoupling of massless o ..."
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Cited by 49 (2 self)
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We study some aspects of open string theories on Dbranes with critical electric fields. We show that the massless open string modes that move in the direction of the electric field decouple. In the 1+1 dimensional case the dual theory is U(N) SYM with electric flux, and the decoupling of massless open strings is dual to the decoupling of the U(1) degrees of freedom. We also show that, if the direction along the electric field is compact, then there are finite energy winding closed string modes. They are dual to Higgs branch excitations of the SYM theory, and their energetics works accordingly. These properties provide new nontrivial evidence for the duality. We study some aspects of noncommutative open string theories. These are open string theories on branes in the presence of a critical electric field. More precisely, they are defined through a scaling limit where the electric field is taken to its critical value [1, 2] (for earlier work, see [3], and for other recent work [4, 5, 6, 7, 8]). The resulting open string theory is the
Observables as twist anomaly in vacuum string field theory
 JHEP
, 2002
"... We reveal a novel mathematical structure in physical observables, the mass of tachyon fluctuation mode and the energy density, associated with a classical solution of vacuum string field theory constructed previously [hepth/0108150]. We find that they are expressed in terms of quantities which appa ..."
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Cited by 44 (8 self)
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We reveal a novel mathematical structure in physical observables, the mass of tachyon fluctuation mode and the energy density, associated with a classical solution of vacuum string field theory constructed previously [hepth/0108150]. We find that they are expressed in terms of quantities which apparently vanish identically due to twist evenodd degeneracy of eigenvalues of a Neumann coefficient matrix defining the threestring interactions. However, they can give nonvanishing values because of the breakdown of the degeneracy at the edge of the eigenvalue distribution. We also present a general prescription of correctly simplifying the expressions of these observables. Numerical calculation of the energy density following our prescription indicates that the present classical solution represents the configuration of two D25branes.
A Solvable Toy Model for Tachyon Condensation in String Field Theory
, 2010
"... The lump solution of φ³ field theory provides a toy model for unstable Dbranes of bosonic string theory. The field theory living on this lump is itself a cubic field theory involving a tachyon, two additional scalar fields, and a scalar field continuum. Its action can be written explicitly because ..."
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Cited by 44 (6 self)
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The lump solution of φ³ field theory provides a toy model for unstable Dbranes of bosonic string theory. The field theory living on this lump is itself a cubic field theory involving a tachyon, two additional scalar fields, and a scalar field continuum. Its action can be written explicitly because the fluctuation spectrum of the lump turns out to be governed by a solvable Schroedinger equation; the ℓ = 3 case of a series of reflectionless potentials. We study the multiscalar tachyon potential both exactly and in the level expansion, obtaining insight into issues of convergence, branches of the solution space, and the mechanism for removal of states after condensation. In particular we find an interpretation for the puzzling finite domain of definition of string field marginal parameters.
New solution of the open bosonic string field theory,” arXiv:hepth/0205294
"... Preprint typeset in JHEP style. HYPER VERSION ..."
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Oscillator Representation of the BCFT Construction of Dbranes in Vacuum String Field Theory
"... Starting from the boundary CFT definition for the Dbranes in vacuum string field theory (VSFT) given in hepth/0105168, we derive the oscillator expression for the D24brane solution in the VSFT on D25brane. We show that the state takes the form of a squeezed state, similar to the one found directl ..."
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Cited by 37 (0 self)
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Starting from the boundary CFT definition for the Dbranes in vacuum string field theory (VSFT) given in hepth/0105168, we derive the oscillator expression for the D24brane solution in the VSFT on D25brane. We show that the state takes the form of a squeezed state, similar to the one found directly in terms of the oscillators and reported in hepth/0102112. Both the solutions are actually one parameter families of solutions. We also find numerical evidence that at least for moderately large values of the parameter (b) in the oscillator construction the two families of solutions are same under a suitable redefinition of the parameter. Finally we generalize the method to computing the oscillator expression for a Dbrane solution with constant gauge field strength turned on along the world volume. 1
Analytical Solutions of Open String Field Theory
, 2008
"... In this work we review Schnabl’s construction of the tachyon vacuum solution to bosonic covariant open string field theory and the results that followed. We survey the state of the art of string field theory research preceding this construction focusing on Sen’s conjectures and the results obtained ..."
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Cited by 36 (8 self)
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In this work we review Schnabl’s construction of the tachyon vacuum solution to bosonic covariant open string field theory and the results that followed. We survey the state of the art of string field theory research preceding this construction focusing on Sen’s conjectures and the results obtained using level truncation methods. The tachyon vacuum solution is described in various ways, in particular we describe its geometric representation using wedge states and its formal algebraic representation as a gauge solution. We also derive the form of the solution’s building blocks in the oscillator representation. We show that some of Sen’s conjectures can be proven analytically using this solution. The tools used in the context of the vacuum solution can be adapted to the construction of other solutions, namely various marginal deformations. We present some of the approaches used in the construction of these solutions. The generalization to open superstring field theory is derived in details. We start from the exposition of the problems one faces in the construction of superstring field
Marginal deformations in string field theory
 JHEP 09 (2007) 101, [arXiv:0704.2222 [hepth]]. (Cited on
"... Abstract: We describe a method for obtaining analytic solutions corresponding to exact marginal deformations in open bosonic string field theory. For the photon marginal deformation we have an explicit analytic solution to all orders. Our construction is based on a pure gauge solution where the gau ..."
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Abstract: We describe a method for obtaining analytic solutions corresponding to exact marginal deformations in open bosonic string field theory. For the photon marginal deformation we have an explicit analytic solution to all orders. Our construction is based on a pure gauge solution where the gauge field is not in the Hilbert space. We show that the solution itself is nevertheless perfectly regular. We study its gauge transformations and calculate some coefficients explicitly. Finally, we discuss how our method can be implemented for other marginal deformations.