Results 1  10
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19
N=4 topological strings
 Nucl. Phys. B
, 1995
"... We show how to make a topological string theory starting from an N = 4 superconformal theory. The critical dimension for this theory is ĉ = 2 (c = 6). It is shown that superstrings (in both the RNS and GS formulations) and critical N = 2 strings are special cases of this topological theory. Applicat ..."
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Cited by 225 (23 self)
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We show how to make a topological string theory starting from an N = 4 superconformal theory. The critical dimension for this theory is ĉ = 2 (c = 6). It is shown that superstrings (in both the RNS and GS formulations) and critical N = 2 strings are special cases of this topological theory. Applications for this new topological theory include: 1) Proving the vanishing to all orders of all scattering amplitudes for the selfdual N = 2 string with flat background, with the exception of the threepoint function and the closedstring partition function; 2) Showing that the topological partition function of the N = 2 string on the K3 background may be interpreted as computing the superpotential in harmonic superspace generated upon compactification of type II superstrings from 10 to 6 dimensions; and 3) Providing a new prescription for calculating superstring amplitudes which appears to be free of totalderivative ambiguities. July
Conformal Field Theory of AdS Background with RamondRamond Flux,” JHEP 9903
, 1999
"... We review a formalism of superstring quantization with manifest sixdimensional spacetime supersymmetry, and apply it to AdS3 × S3 backgrounds with RamondRamond flux. The resulting description is a conformal field theory based on a sigma model whose target space is a certain supergroup SU ′(22). F ..."
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Cited by 142 (16 self)
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We review a formalism of superstring quantization with manifest sixdimensional spacetime supersymmetry, and apply it to AdS3 × S3 backgrounds with RamondRamond flux. The resulting description is a conformal field theory based on a sigma model whose target space is a certain supergroup SU ′(22). February
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
Covariant Quantization of the GreenSchwarz Superstring in a CalabiYau Background”, Nucl. Phys. B431
, 1994
"... After adding a scalar chiral boson to the usual superspace variables, the fourdimensional GreenSchwarz superstring is quantized in a manifestly SO(3,1) superPoincaré covariant manner. The constraints are all firstclass and form an N=2 superconformal algebra with c = −3. Since the CalabiYau degr ..."
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Cited by 63 (20 self)
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After adding a scalar chiral boson to the usual superspace variables, the fourdimensional GreenSchwarz superstring is quantized in a manifestly SO(3,1) superPoincaré covariant manner. The constraints are all firstclass and form an N=2 superconformal algebra with c = −3. Since the CalabiYau degrees of freedom are described by an N=2 superconformal field theory with c = 9, the combined GreenSchwarz and CalabiYau systems form the c = 6 matter sector of a critical N=2 string. Using the standard N=2 superVirasoro ghosts, a nilpotent BRST charge is defined and vertex operators for the massless supermultiplets are constructed. Fourdimensional superstring amplitudes can be calculated with manifest SO(3,1) superPoincaré invariance by evaluating correlation functions of these BRSTinvariant In previous papers by this author, 1−4 it was shown that the tendimensional GreenSchwarz superstring can be quantized with free fields by constructing a nilpotent BRST operator out of an N=2 stressenergy tensor with critical central charge c = 6. Scattering amplitudes are calculated by evaluating correlation functions of BRSTinvariant vertex operators on N=2 superRiemann surfaces, where the integration over
Pure Spinor Formalism as an N=2 Topological String
, 2005
"... Following suggestions of Nekrasov and Siegel, a nonminimal set of fields are added to the pure spinor formalism for the superstring. Twisted ĉ = 3 N=2 generators are then constructed where the pure spinor BRST operator is the fermionic spinone generator, and the formalism is interpreted as a criti ..."
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Cited by 36 (7 self)
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Following suggestions of Nekrasov and Siegel, a nonminimal set of fields are added to the pure spinor formalism for the superstring. Twisted ĉ = 3 N=2 generators are then constructed where the pure spinor BRST operator is the fermionic spinone generator, and the formalism is interpreted as a critical topological string. Three applications of this topological string theory include the superPoincaré covariant computation of multiloop superstring amplitudes without picturechanging operators, the construction of a cubic open superstring field theory without contactterm problems, and a new fourdimensional version of the pure spinor formalism which computes Fterms in the spacetime action.
On the Uniqueness of String Theory
, 1994
"... We show that bosonic strings may be viewed as a particular class of vacua for N = 1 superstrings, and N = 1 superstrings may be viewed as a particular class of vacua for N = 2 strings. Continuing this line of string hierarchies, we are led to search for a universal string theory which includes all t ..."
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Cited by 30 (5 self)
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We show that bosonic strings may be viewed as a particular class of vacua for N = 1 superstrings, and N = 1 superstrings may be viewed as a particular class of vacua for N = 2 strings. Continuing this line of string hierarchies, we are led to search for a universal string theory which includes all the rest as a special vacuum selection. 10/93 One of the most beautiful aspects of string theory is that it has almost no adjustable parameters. The main choice to be made is the selection of a string vacuum. The only nonunique feature seems to be the selection of which worldsheet symmetries we are gauging. If we take the worldsheet gravity theory to be pure gravity (N=0), we get the bosonic strings, for N = 1 supergravity we get the fermionic string, and for N = 2 supergravity we get the N = 2 strings. For closed strings, we can also choose heterotic combinations (p, q) depending on which symmetries we choose for the left or rightmoving degrees of freedom (the most well known example being the (0,1) heterotic string). In this paper we show that the choice of which string we consider may also be viewed just as another choice of string vacuum. In particular we will show that any string vacuum for a (p, q) string can be viewed as a special choice of the string vacuum for (p′, q ′) string with 0 ≤ p ≤ p ′ ≤ 2
On the picture dependence of RamondRamond cohomology, Nucl. Phys. B523
, 1998
"... Closed string physical states are BRST cohomology classes computed on the space of states annihilated by b − 0. Since b − 0 does not commute with the operations of picture changing, BRST cohomologies at different pictures need not agree. We show explicitly that RamondRamond (RR) zeromomentum physi ..."
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Cited by 11 (0 self)
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Closed string physical states are BRST cohomology classes computed on the space of states annihilated by b − 0. Since b − 0 does not commute with the operations of picture changing, BRST cohomologies at different pictures need not agree. We show explicitly that RamondRamond (RR) zeromomentum physical states are inequivalent at different pictures, and prove that nonzero momentum physical states are equivalent in all pictures. We find that Dbrane states represent BRST classes that are nonpolynomial on the superghost zero modes, while RR gauge fields appear as polynomial BRST classes. We also prove that in xcohomology, the cohomology where the zero mode of the spatial coordinates is included, there is a unique ghostnumber one BRST class responsible for the GreenSchwarz anomaly, and a unique ghost number minus one BRST class associated with RR charge.
Black Hole Partition Function using Hybrid Formalism of Superstrings
, 811
"... The hybrid formalism of superstrings on AdS2 × S 2, defined as a sigma model on the coset supermanifold PSU(1,12)/U(1) × U(1) with a WZ term, is used to calculate the instanton partition function of IIA superstrings on the euclidean attractor geometry AdS2 × S 2 × CY3. A nilpotent BRST operator is ..."
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Cited by 2 (0 self)
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The hybrid formalism of superstrings on AdS2 × S 2, defined as a sigma model on the coset supermanifold PSU(1,12)/U(1) × U(1) with a WZ term, is used to calculate the instanton partition function of IIA superstrings on the euclidean attractor geometry AdS2 × S 2 × CY3. A nilpotent BRST operator is constructed and the sigma model action is shown to be closed. The BRST operator is then used to regularize the divergence over the AdS2 part and the In [1], OSV conjectured a relationship of the form: ZBH = Ztop  2 (1)
Type IIB Flux Vacua from the String
, 804
"... Abstract: We study type IIB string compactifications in the presence of RR and NSNS fluxes using worldsheet techniques. Vertex operators corresponding to internal RR and NSNS fluxes are constructed in the hybrid formalism with manifest target space supersymmetry. In a simple class of examples, we co ..."
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Abstract: We study type IIB string compactifications in the presence of RR and NSNS fluxes using worldsheet techniques. Vertex operators corresponding to internal RR and NSNS fluxes are constructed in the hybrid formalism with manifest target space supersymmetry. In a simple class of examples, we compute various known physical phenomena such as warping and the generation of a superpotential for complex structure
Superstring Theory on AdS2 × S 2
, 1999
"... We quantize the superstring on the AdS2 × S 2 background with RamondRamond flux using a PSU(1, 12)/U(1) × U(1) sigma model with a WZ term. Oneloop conformal invariance of the model is guaranteed by a general mechanism which holds for coset spaces G/H where G is Ricciflat and H is the invariant ..."
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We quantize the superstring on the AdS2 × S 2 background with RamondRamond flux using a PSU(1, 12)/U(1) × U(1) sigma model with a WZ term. Oneloop conformal invariance of the model is guaranteed by a general mechanism which holds for coset spaces G/H where G is Ricciflat and H is the invariant locus of a Z4 automorphism of G. This mechanism gives conformal theories for the PSU(1, 12) × PSU(22)/SU(2) × SU(2) and PSU(2, 24)/SO(4, 1) × SO(5) coset spaces, suggesting our results might be useful for quantizing the superstring on AdS3 × S 3 and AdS5 × S 5 backgrounds. July