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140
Open string states around a classical solution in vacuum string field theory
, 2001
"... We construct a classical solution of vacuum string field theory (VSFT) and study whether it represents the perturbative open string vacuum. Our solution is given as a squeezed state in the Siegel gauge, and it fixes the arbitrary coefficients in the BRST operator in VSFT. We identify the tachyon and ..."
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Cited by 85 (9 self)
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We construct a classical solution of vacuum string field theory (VSFT) and study whether it represents the perturbative open string vacuum. Our solution is given as a squeezed state in the Siegel gauge, and it fixes the arbitrary coefficients in the BRST operator in VSFT. We identify the tachyon and massless vector states as fluctuation modes around the classical solution. The tachyon mass squared α ′ m 2 t is given in a closed form using the Neumann coefficients defining the threestring vertex, and it reproduces numerically the expected value of −1 to high precision. The ratio of the potential height of the solution to the D25brane tension is also given in terms of the Neumann coefficients. However, the behavior of the potential height in level truncation does not match our expectation, though there are subtle points in the analysis.
Boundary CFT Construction of Dbranes in Vacuum String Field Theory
, 2001
"... In previous papers we built (multiple) Dbranes in flat spacetime as classical solutions of the string field theory based on the tachyon vacuum. In this paper we construct classical solutions describing all Dbranes in any fixed spacetime background defined by a two dimensional CFT of central char ..."
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Cited by 80 (6 self)
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In previous papers we built (multiple) Dbranes in flat spacetime as classical solutions of the string field theory based on the tachyon vacuum. In this paper we construct classical solutions describing all Dbranes in any fixed spacetime background defined by a two dimensional CFT of central charge 26. A key role is played by the geometrical definition of the sliver state in general boundary CFT’s. The correct values for ratios of Dbrane tensions arise because the norm of the sliver solution is naturally related to the disk partition function of the appropriate boundary CFT. We also explore the possibility of reproducing the known spectrum of physical states on a Dbrane as deformations of the sliver.
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.
Time evolution in superstring field theory on nonBPS brane. I: Rolling tachyon and energymomentum conservation,” JHEP 09
, 2003
"... We derive equations of motion for the tachyon field living on an unstable nonBPS Dbrane in the level truncated open cubic superstring field theory in the first nontrivial approximation. We construct a special time dependent solution to this equation which describes the rolling tachyon. It starts ..."
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Cited by 63 (10 self)
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We derive equations of motion for the tachyon field living on an unstable nonBPS Dbrane in the level truncated open cubic superstring field theory in the first nontrivial approximation. We construct a special time dependent solution to this equation which describes the rolling tachyon. It starts from the perturbative vacuum and approaches one of stable vacua in infinite time. We investigate conserved energy functional and show that its different parts dominate in different stages of the evolution. We show that the pressure for this solution has its minimum at zero time and maximum at infinite time. Contents 1
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.
Wedge states in string field theory
 JHEP
, 2003
"... The wedge states form an important subalgebra in the string field theory. We review and further investigate their various properties. We find in particular a novel expression for the wedge states, which allows to understand their star products purely algebraically. The method allows also for treatin ..."
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Cited by 50 (2 self)
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The wedge states form an important subalgebra in the string field theory. We review and further investigate their various properties. We find in particular a novel expression for the wedge states, which allows to understand their star products purely algebraically. The method allows also for treating the matter and ghost sectors separately. It turns out, that wedge states with different matter and ghost parts violate the associativity of the algebra. We introduce and study also wedge states with insertions of local operators and show how they are useful for obtaining exact results about convergence of level truncation calculations. These results help to clarify the issue of anomalies related to the identity and some exterior derivations in the string field algebra. 1
New solution of the open bosonic string field theory,” arXiv:hepth/0205294
"... Preprint typeset in JHEP style. HYPER VERSION ..."
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Marginal Solutions for the Superstring
 J. High Energy Phys
"... We construct a class of analytic solutions of WZWtype open superstring field theory describing marginal deformations of a reference Dbrane background. The deformations we consider are generated by onshell vertex operators with vanishing operator products. The superstring solution exhibits an intr ..."
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Cited by 40 (6 self)
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We construct a class of analytic solutions of WZWtype open superstring field theory describing marginal deformations of a reference Dbrane background. The deformations we consider are generated by onshell vertex operators with vanishing operator products. The superstring solution exhibits an intriguing duality with the corresponding marginal solution of the bosonic string. In particular, the superstring problem is “dual ” to the problem of reexpressing the bosonic marginal solution in pure gauge form. This represents the first nonsingular analytic
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 35 (9 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