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Dimitri Polyakov

Publications and source records attributed to Dimitri Polyakov.

49 records · Page 3Linked to original sources

BRST Properties of New Superstring States

Brane-like states are defined by physical vertex operators in NSR superstring theory, existing at nonzero pictures only. These states exist both in open and closed string theories, in the NS and NS-NS sectors respectively. In this paper we present a detailed analysis of their BRST properties, giving a proof that these vertex operators are physical, i.e. BRST invariant and BRST non-trivial.

hep-th

World Sheet Logarithmic CFT in AdS Strings, Ghost-Matter Mixing and M-theory

We discuss several closely related concepts in the NSR formulation of superstring theory. We demonstrated that recently proposed NSR model for superstrings on $AdS_5 \times S^5$ is described by the world-sheet logarithmic conformal field theory (LCFT). The origin of LCFT on a world-sheet is closely connected to the matter-ghost mixing in the structure of a brane-like vortex operators. We suggest a dynamical origin of M theory as a string theory with an extra dimension given by bosonised superconformal ghosts.

hep-th

AdS/CFT Correspondence, Critical Strings and Stochastic Quantization

We show that dilaton beta-function equation in the brane-like sigma-model (regarded as NSR analogue of string theory on $AdS_5\times{S^5}$) has the form of stochastic Langevin equation with non-Markovian noise. The worldsheet cutoff is identified with stochastic time and the $V_5$-operator plays the role of the noise. We derive the Fokker-Planck equation associated with this stochastic process and show that the Hamiltonian of the $AdS_5$ supergravity defines the distribution satisfying this Fokker-Planck equation. This means that the dynamical compactification of flat ten-dimensional space-time on $AdS_5\times{S^5}$ occurs as a result of the non-Markovian stochastic process, generated by the $V_5$-operator noise. This provides us with an insight into relation between holography principle and the concept of stochastic quantization from the point of view of critical string theory.

hep-th

On the NSR formulation of String Theory on AdS_5 X S^5

We discuss the NSR formulation of the superstring action on AdS_5 X S^5 proposed recently by Kallosh and Tseytlin in the Green-Schwarz formalism.We show that the stress-energy tensor corresponding to the NSR action for AdS superstring contains the branelike terms, corresponding to exotic massless vertex operators (refered to as the branelike vertices). The corresponding sigma-model action has the manifest SO(1,3) X SO(6) invariance of superstring theory on AdS_5 X S^5. We argue that adding the branelike terms is equivalent to curving the space-time to obtain the AdS_5 X S^5 background. We commence the study of the proposed NSR sigma-model by analyzing the scattering amplitudes involving the branelike vertex operators.The analysis shows quite an unusual momentum dependence of these scattering amplitudes.

hep-th

Brane-like States in Superstring Theory and the Dynamics of non-Abelian Gauge Theories

We propose a string-theoretic ansatz describing the dynamics of SU(N) Yang-Mills theories in the limit of large N in D=4. The construction uses in a crucial way open-string vertex operators that describe non-perturbative brane dynamics. According to our proposal, various gauge theories are described by string theories with the same action, but with different measures in the functional integral. The choice of measure defines the gauge group, as well as the effective space-time dimension of the resulting gauge theory.

hep-th

Ghost Number Cohomologies and M-theory Quantum States

We review and develop the formalism of ghost number cohomologies, outlined in our previous work, to classify the quantum states of M-theory. We apply this formalism to the matrix formulation of M-theory to obtain NSR superstring action from dimensionally reduced matrix model. The BPS condition of the matrix theory is related to the worldsheet reparametrizational invariance in superstring theory, underlining the connection between unbroken supersymmetries in M-theory and superstring gauge symmetries.

hep-th

A Comment on a Fivebrane Term in Superalgebra

We review our recent discussion of fivebrane central terms that appear in the space-time superalgebra in D=10 provided that the space-time supercharges are taken in non-canonical pictures. We correct the mistake contained in the original version of the earlier paper hep-th/9703008 which suggested that the naive picture-changing of the superalgebra could give rise to the non-perturbative five-form term. The relation between picture-changing and p-brane central terms appears to be much more subtle, as is pointed out in the revised version of the mentioned paper.

hep-th

S-Duality as an Open String Gauge Symmetry

The paper discusses the connection between S-duality and string-theoretic picture-changing formalism. The singular limit of the picture-changing transformation at zero momentum leads to the presence of the topological 5-form charge in the type IIB superalgebra which is attributed to the M5-brane. The topological charge defines the boundary D-brane state, which also is the analogue of the monopole part of the Olive-Witten's result in field theory.The correlation functions involving this non-perturbative state are computed.The non-perturbative D-brane states are associated with the ghost number cohomologies, introduced in the paper. Connections with M(atrix) theory are discussed.

hep-th

Kappa-Symmetry and Bogomol'ny Bound

The paper analyzes the problem fixing the local fermionic gauge symmetry in the Green-Schwarz superstring theory,related to the covariant quantization of this theory.The gauge-fixing procedure reveals the connection between GS and NSR formalisms, conjectured earlier. The analysis relates the kappa-invariance to the Bogomol'ny-type condition,well-known in connection with D-brane theories. The BPS saturation condition appears to be a target space superpartner of the kappa-invariance condition. Relation to RR charges of p-brane solutions of the ten-dimensional supergravity is discussed.

hep-th

RR-Dilaton Interaction in a Type IIB Superstring

We analyze the interaction between the massless RR states with a dilaton in a type IIB superstring. By constructing vertex operators for massless and massive RR states and computing their correlation functions with a dilaton we find the Ramond-Ramond part of the superstring low-energy effective action. The RR terms appearing in the action do not contain the standard dilatonic factor (string coupling constant). The geometrical interpretation of this fact is presented. Namely we argue that the spin operators in the RR vertices effectively decrease the Euler character of the worldsheet by 1 unit. As a result, the additional dilatonic term proportional to string coupling constant appears in the worldsheet string action.

hep-th

Picture-Changing operators and Space-Time supersymmetry

We explore geometrical properties of fermionic vertex operators for a NSR superstring in order to establish connection between worldsheet and target space supersymmetries. The mechanism of picture-changing is obtained as a result of imposing certain constraints on a world-sheet gauge group of the NSR theory. It is found that picture-changing operators of various integer ghost numbers form a polynomial ring. By using properties of the picture-changing formalism we establish connection between the NSR and GS superstring theories. We explore the properties of the $κ$-symmetry in the NSR formalism and show that it leads to some new identities between correlation functions.

hep-th

Curvature Singularity as the Vertex Operator

The submitted paper regards the example of the Conformal Field Theory on a 2d manifold which metric has a point-like singularity.Since this manifold is not conformally equivalent to that with the flat space-time metric,it's naturally to expect that the theory cannot be trivially reduced to the well-known consideration of the CFT on a plane,and some modifications are needed.Particularly,this paper shows how the vacuum of the theory on a singular surface differs from the vacuum of the BPZ theory.Namely,this vacuum would not be SL(2,C)-invariant and the expressions for the correlation functions should be modified. As a consequence of that,some "effective mass" is brought to the theory.

hep-th