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179
String Field Theory Around the Tachyon Vacuum
, 2000
"... Assuming that around the tachyon vacuum the kinetic term of cubic open string field theory is made purely of ghost operators we are led to gauge invariant actions which manifestly implement the absence of open string dynamics around this vacuum. We test this proposal by showing the existence of lump ..."
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Cited by 151 (6 self)
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Assuming that around the tachyon vacuum the kinetic term of cubic open string field theory is made purely of ghost operators we are led to gauge invariant actions which manifestly implement the absence of open string dynamics around this vacuum. We test this proposal by showing the existence of lump solutions of arbitrary codimension in this string field theory. The key ingredients in this analysis are certain assumptions about the analyticity properties of tachyon Green’s functions. With the help of some further assumptions about the properties of these Green’s functions, we also calculate the ratios of tensions of lump solutions of different dimensions. The result is in perfect agreement with the known answers for the ratios of tensions of Dbranes of different dimensions.
Classical Solutions in String Field Theory Around the Tachyon Vacuum
, 2001
"... In a previous paper [hepth/0012251] we proposed a simple class of actions for string field theory around the tachyon vacuum. In this paper we search for classical solutions describing Dbranes of different dimensions using the ansatz that the solutions factorize into the direct product of a matter ..."
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Cited by 110 (5 self)
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In a previous paper [hepth/0012251] we proposed a simple class of actions for string field theory around the tachyon vacuum. In this paper we search for classical solutions describing Dbranes of different dimensions using the ansatz that the solutions factorize into the direct product of a matter state and a universal ghost state. We find closed form expressions for the matter state describing Dbranes of all dimensions. For the space filling D25brane the state is the matter part of the zero angle wedge state, the “sliver”, built in [hepth/0006240]. For the other Dbrane solutions the matter states are constructed using a solution generating technique outlined in [hepth/0008252]. The ratios of tensions of various Dbranes, requiring evaluation of determinants of infinite dimensional matrices, are calculated numerically and are in very good agreement with the known results.
Comments on Schnabl’s analytic solution for tachyon condensation in Witten’s open string field theory
 hepth/0603159. – 9
"... open string field theory ..."
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A note on background independence in noncommutative gauge theories, matrix model and tachyon condensation
 JHEP
"... Using the construction of Dbranes with nonzero B field in the matrix model we give a physical interpretation of the known background independence in gauge theories on a noncommutative space. The background independent variables are identified as the degrees of freedom of the underlying matrix model ..."
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Cited by 93 (0 self)
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Using the construction of Dbranes with nonzero B field in the matrix model we give a physical interpretation of the known background independence in gauge theories on a noncommutative space. The background independent variables are identified as the degrees of freedom of the underlying matrix model. This also clarifies and extends some recent Dbranes with nonzero B field have recently figured in different contexts in string theory. They were shown to arise in the matrix model [1], where an infinite collection of D0branes can make higher Dpbranes [1,2,3]. This motivated the discovery of noncommutative geometry in string theory [4,5], which was later studied by various authors including [6,7].
Proof of vanishing cohomology at the tachyon vacuum
, 2006
"... We prove Sen’s third conjecture that there are no onshell perturbative excitations of the tachyon vacuum in open bosonic string field theory. The proof relies on the existence of a special state A, which, when acted on by the BRST operator at the tachyon vacuum, gives the identity. While this state ..."
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Cited by 87 (7 self)
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We prove Sen’s third conjecture that there are no onshell perturbative excitations of the tachyon vacuum in open bosonic string field theory. The proof relies on the existence of a special state A, which, when acted on by the BRST operator at the tachyon vacuum, gives the identity. While this state was found numerically in FeynmanSiegel gauge, here we give a simple analytic expression.
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.
Large marginal deformations in string field theory
 JHEP 0010
, 2000
"... We use the level truncation scheme to obtain accurate descriptions of open bosonic string field configurations corresponding to large marginal deformations such as background Wilson lines. To do so, we solve for all fields as functions of the massless string field, and confirm that the effective pot ..."
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Cited by 67 (18 self)
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We use the level truncation scheme to obtain accurate descriptions of open bosonic string field configurations corresponding to large marginal deformations such as background Wilson lines. To do so, we solve for all fields as functions of the massless string field, and confirm that the effective potential of the massless field becomes increasingly flat as the level of approximation is increased. Surprisingly, as a result of the merging of two branches of the solution one originating at zero tachyon vev and the other originating at the tachyonic vacuum this effective potential exists only for a finite range of values of the massless field. We use the D1 to D0 brane marginal transition on a circle to explore the possibility that this finite range corresponds to the infinite range of the conformal field theory parameter describing marginal deformations, but are unable to arrive at a definitive conclusion.
Comments on marginal deformations in open string field theory
"... In this short letter we present a class of remarkably simple solutions to Witten’s open string field theory that describe marginal deformations of the underlying boundary conformal field theory. The solutions we consider correspond to dimensionone matter primary operators that have nonsingular ope ..."
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Cited by 65 (2 self)
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In this short letter we present a class of remarkably simple solutions to Witten’s open string field theory that describe marginal deformations of the underlying boundary conformal field theory. The solutions we consider correspond to dimensionone matter primary operators that have nonsingular operator products with themselves. We briefly discuss application to rolling tachyons. 1 1