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84
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.
Solving open string field theory with special projectors,” hepth/0606131
"... Schnabl recently found an analytic expression for the string field tachyon condensate using a gauge condition adapted to the conformal frame of the sliver projector. We propose that this construction is more general. The sliver is an example of a special projector, a projector such that the Virasoro ..."
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Cited by 57 (5 self)
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Schnabl recently found an analytic expression for the string field tachyon condensate using a gauge condition adapted to the conformal frame of the sliver projector. We propose that this construction is more general. The sliver is an example of a special projector, a projector such that the Virasoro operator L0 and its BPZ adjoint L ⋆ 0 obey the algebra [L0, L ⋆ 0] = s(L0 + L ⋆ 0), with s a positive real constant. All special projectors provide abelian subalgebras of string fields, closed under both the ∗product and the action of L0. This structure guarantees exact solvability of a ghost number zero string field equation. We recast this infinite recursive set of equations as an ordinary differential equation that is easily solved. The classification of special projectors is reduced to a version of the RiemannHilbert problem, with piecewise constant data on the boundary of a disk.
Ratio of Tensions from Vacuum String Field Theory,” arXiv:hepth/0201136
"... We show analytically that the ratio of the norm of sliver states agrees with the ratio of Dbrane tensions. We find that the correct ratio appears as a twist anomaly. Vacuum String Field Theory (VSFT) is proposed [1] as a bosonic open string field theory around the closed string vacuum. (See [2–23] ..."
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Cited by 47 (0 self)
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We show analytically that the ratio of the norm of sliver states agrees with the ratio of Dbrane tensions. We find that the correct ratio appears as a twist anomaly. Vacuum String Field Theory (VSFT) is proposed [1] as a bosonic open string field theory around the closed string vacuum. (See [2–23] for related papers.) One of the interesting problems in VSFT is to reconstruct the unstable vacua describing Dbranes as classical solutions of VSFT and extract the physical quantities such as the ratio of tensions
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.
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
Open string states and Dbrane tension from vacuum string field theory
 JHEP
, 2002
"... We propose a description of open string fields on a D25brane in vacuum string field theory. We show that the tachyon mass is correctly reproduced from our proposal and further argue that the mass spectrum of all other open string states is correctly obtained as well. We identify the string coupling ..."
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Cited by 35 (5 self)
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We propose a description of open string fields on a D25brane in vacuum string field theory. We show that the tachyon mass is correctly reproduced from our proposal and further argue that the mass spectrum of all other open string states is correctly obtained as well. We identify the string coupling constant from the threetachyon coupling and show that the tension of a D25brane is correctly expressed in terms of the coupling constant, which resolves the controversy in the literature. We also discuss a reformulation of our description which is rather similar to boundary string One of the most crucial open problems regarding vacuum string field theory (VSFT) [1] is that while ratios of tensions of various Dbranes can be reproduced [2], the tension of a single D25brane has not yet been obtained correctly. Another important problem is that we do not completely understand how to describe open string states around
CFT description of identity string field: Toward derivation of the VSFT action
 JHEP 0205
, 2002
"... We concretely define the identity string field as a surface state and deal with it consistently in terms of conformal field theory language, never using its formal properties nor oscillator representation of it. The generalized gluing and resmoothing theorem provides us with a powerful computational ..."
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Cited by 34 (3 self)
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We concretely define the identity string field as a surface state and deal with it consistently in terms of conformal field theory language, never using its formal properties nor oscillator representation of it. The generalized gluing and resmoothing theorem provides us with a powerful computational tool which fits into our framework. Among others, we can prove that in some situations the identity state defined this way actually behaves itself like an identity element under the ∗product. We use these CFT techniques to give an explicit expression of the classical solution in the ordinary cubic string field theory having the property that the conjectured vacuum string field theory action arises when the cubic action is expanded around it. 1
The spectrum of Neumann Matrix with Zero Modes
"... Preprint typeset in JHEP style. HYPER VERSION ..."
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