0000000000718538

AUTHOR

A. Abdurrahman

Factorization in closed string field theory

Abstract The so long made assumption, that a general closed-string vertex operator V should be built as a product of left- and right-moving vertex operators, rests on the fact that the closed-string Fock spce is constructed as a tensor product of left- and right-moving open-string Fock spaces. In this letter we will relax this assumption by proving that factorization of closed-string vertices is a general rule.

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Witten's Cubic Vertex in the Comma Theory (I)

In is shown explicitly that the Witten's interaction 3-vertex is a solution to the comma overlap equations; hence establishing the equivalence between the conventional and the "comma" formulation of interacting string theory at the level of vertices.

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Bose-Fermi equivalence and interacting string field theory

Abstract We show that the bosonic and the fermionic realization of the ghost vertex in the Half-String (HS) Operator approach to Witten's String Field Theory (WSFT) are equivalent. In the process we discover that higher vertices (i.e., N > 3) can be eliminated in WSFT using only the overlap conditions defining the interaction vertex and ghost number counting.

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Operator approach to the Gluing Theorem in String Field Theory

An algebraic proof of the Gluing Theorem at tree level of perturbation theory in String Field Theory is given. Some applications of the theorem to closed string non-polynomial action are briefly discussed

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Half-string oscillator approach to string field theory

In this letter we present an operator formalism for Closed String Field Theory based on closed half-strings. Our results indicate that the restricted polyhedra of the classical non-polynomial string field theory, can be represented as traces of infinite matrices, with operator insertions that reparametrise the half-strings.

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Relationship between the comma theory and Witten’s string field theory

The comma representation of interacting string field theory is further elucidated. The proof that Witten's vertex solves the comma overlap equations is established. In this representation, the associativity of the star algebra is seen to hold. The relationship of the symmetry K in the standard formulation of Witten's string field theory to that in the comma theory is discussed.

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N-string vertices in string field theory.

We give the general form of the vertex corresponding to the interaction of an arbitrary number of strings. The technique employed relies on the ``comma" representation of String Field Theory where string fields and interactions are represented as matrices and operations between them such as multiplication and trace. The general formulation presented here shows that the interaction vertex of N strings, for any arbitrary N, is given as a function of particular combinations of matrices corresponding to the change of representation between the full string and the half string degrees of freedom.

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The three-vertex in the closed half-string field theory and the general gluing and resmoothing theorem

In this letter we prove that the half-string three-vertex in closed string field theory satisfies the general gluing and resmoothing theorem. We also demonstrate how one calculates amplitudes in the half-string approach to closed string field theory, by working out explicitly a few simple three-amplitudes.

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