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140
Tachyon condensation in string field theory
 JHEP 0003 (2000) 002 [arXiv:hepth/9912249
"... It has been conjectured that at a stationary point of the tachyon potential for the Dbrane of bosonic string theory, the negative energy density exactly cancels the Dbrane tension. We evaluate this tachyon potential by offshell calculations in open string field theory. Surprisingly, the condensat ..."
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Cited by 221 (9 self)
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It has been conjectured that at a stationary point of the tachyon potential for the Dbrane of bosonic string theory, the negative energy density exactly cancels the Dbrane tension. We evaluate this tachyon potential by offshell calculations in open string field theory. Surprisingly, the condensation of the tachyon mode alone into the stationary point of its cubic potential is found to cancel about 70 % of the Dbrane tension. Keeping relevant scalars up to four mass levels above the tachyon, the energy density at the shifted stationary point cancels 99 % of the Dbrane tension.
Tachyon potentials, star products and universality
 JHEP 0109 (2001) 038 [arXiv:hepth/0006240
"... We develop an efficient recursive method to evaluate the tachyon potential using the relevant universal subalgebra of the open string star algebra. This method, using offshell versions of Virasoro Ward identities, avoids explicit computation of conformal transformations of operators and does not re ..."
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Cited by 179 (18 self)
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We develop an efficient recursive method to evaluate the tachyon potential using the relevant universal subalgebra of the open string star algebra. This method, using offshell versions of Virasoro Ward identities, avoids explicit computation of conformal transformations of operators and does not require a choice of background. We illustrate the procedure with a pedagogic computation of the level six tachyon potential in an arbitrary gauge, and the evaluation of a few simple star products. We give a background independent construction of the socalled identity of the star algebra, and show how it fits into family of string fields generating a commutative subalgebra. 1
Universality of the Tachyon Potential
 J. High Energy Phys
, 1999
"... Using string field theory, we argue that the tachyon potential on a Dbrane antiDbrane system in type II string theory in arbitrary background has a universal form, independent of the boundary conformal field theory describing the brane. This implies that if at the minimum of the tachyon potential ..."
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Cited by 175 (8 self)
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Using string field theory, we argue that the tachyon potential on a Dbrane antiDbrane system in type II string theory in arbitrary background has a universal form, independent of the boundary conformal field theory describing the brane. This implies that if at the minimum of the tachyon potential the total energy of the brane antibrane system vanishes in a particular background, then it vanishes in any other background. Similar result holds for the tachyon potential of the nonBPS Dbranes of type II string theory, and the Dbranes of bosonic string theory. 1
Dbranes and deformation quantization
 JHEP
, 1999
"... In this note we explain how worldvolume geometries of Dbranes can be reconstructed within the microscopic framework where Dbranes are described through boundary conformal field theory. We extract the (noncommutative) worldvolume algebras from the operator product expansions of open string verte ..."
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Cited by 140 (17 self)
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In this note we explain how worldvolume geometries of Dbranes can be reconstructed within the microscopic framework where Dbranes are described through boundary conformal field theory. We extract the (noncommutative) worldvolume algebras from the operator product expansions of open string vertex operators. For branes in a flat background with constant nonvanishing Bfield, the operator products are computed perturbatively to all orders in the field strength. The resulting series coincides with Kontsevich’s presentation of the Moyal product. After extending these considerations to fermionic fields we conclude with some remarks on the generalization of our approach to curved backgrounds.
A Review on Tachyon Condensation in Open String Field Theories
"... We review the recent studies of tachyon condensation in string field theory. After introducing the open string field theory both for bosonic string and for superstring, we use them to examine the conjecture that the unstable configurations of the Dbrane will decay into the ‘closed string vacuum ’ t ..."
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Cited by 140 (4 self)
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We review the recent studies of tachyon condensation in string field theory. After introducing the open string field theory both for bosonic string and for superstring, we use them to examine the conjecture that the unstable configurations of the Dbrane will decay into the ‘closed string vacuum ’ through the tachyon condensation. And we describe the attemps to construct a lower dimensional bosonic Dbrane as an unstable lump solution of the string field equation. We obtain exact results from another formulation, background independent open string field theory. We also discuss some other topics which are related to tachyon condensation in string theory, such as the construction of a Dbrane as a noncommutative soliton
Spacetime Instanton Corrections in 4D String Vacua (The Seesaw Mechanism for DBrane Models)
, 2006
"... We systematically investigate instanton corrections from wrapped Euclidean Dbranes to the matter field superpotential of various classes of N=1 supersymmetric Dbrane models in four dimensions. Both gauge invariance and counting fermionic zero modes provide strong constraints on the allowed nonper ..."
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Cited by 136 (28 self)
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We systematically investigate instanton corrections from wrapped Euclidean Dbranes to the matter field superpotential of various classes of N=1 supersymmetric Dbrane models in four dimensions. Both gauge invariance and counting fermionic zero modes provide strong constraints on the allowed nonperturbative superpotential couplings. We outline how the complete instanton computation boils down to the computation of open string disc diagrams for boundary changing operators multiplied by a oneloop vacuum diagram. For concreteness we focus on E2instanton effects in Type IIA vacua with intersecting D6branes, however the same structure emerges for Type IIB and heterotic vacua. The instantons wrapping rigid cycles can potentially destabilise the vacuum or generate perturbatively absent matter couplings such as proton decay operators, µparameter or righthanded neutrino Majorana mass terms. The latter allow the realization of the seesaw mechanism for MSSM like intersecting Dbrane models.
Noncommutative worldvolume geometries
 BRANES ON SU(2) AND FUZZY SPHERES, JHEP 09
, 1999
"... The geometry of Dbranes can be probed by open string scattering. If the background carries a nonvanishing Beld, the worldvolume becomes noncommutative. Here we explore the quantization of worldvolume geometries in a curved background with nonzero NeveuSchwarz 3form eld strength H = dB. Usin ..."
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Cited by 82 (8 self)
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The geometry of Dbranes can be probed by open string scattering. If the background carries a nonvanishing Beld, the worldvolume becomes noncommutative. Here we explore the quantization of worldvolume geometries in a curved background with nonzero NeveuSchwarz 3form eld strength H = dB. Using exact and generally applicable methods from boundary conformal eld theory, we study the example of open strings in the SU(2) WessZuminoWitten model, and establish a relation with fuzzy spheres or certain (nonassociative) deformations thereof. These ndings could be of direct relevance for Dbranes in the presence of NeveuSchwarz 5branes; more importantly, they provide insight into a completely new class of worldvolume geometries.
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.
Rolling tachyons and decaying branes
 JHEP 0302
"... We present new rolling tachyon solutions describing the classical decay of Dbranes. Our methods are simpler than those appearing in recent works, yet our results are exact in classical string theory. The role of pressure in the decay is studied using tachyon profiles with spatial variation. In this ..."
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Cited by 72 (1 self)
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We present new rolling tachyon solutions describing the classical decay of Dbranes. Our methods are simpler than those appearing in recent works, yet our results are exact in classical string theory. The role of pressure in the decay is studied using tachyon profiles with spatial variation. In this case the final state involves an array of codimension one Dbranes rather than static, pressureless tachyon matter. 1 1
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.