Open Bosonic String Field Theory Research Articles

Algebra of reparametrization-invariant and normal-ordered operators in open string field theory

Normal-ordered reparametrization invariant operators of the open bosonic string field theory include, besides the Poincaré group generators, the ghost number operator, and two translationally invariant symmetric second-rank space-time tensors, with the BRST operator as the trace of the fermionic one. We study their algebra, and find that it closes only when appropriate projections of the fermionic tensor are taken. There are three types of solutions. The first one contains the full Lorentz generatirs in 26 dimensions, the ghost number operator and the usual BRST charge. The second breaks Lorentz invariance down to SO(1, 1) ⊗ SO(24), contains inter alia a new nilpotent operator with cohomology made up of null states. The third class breaks the Lorentz group completely.

Algebraic characterization of the Witten vertex

The Witten vertex of open bosonic string field theory is characterized by a set of algebraic properties written down in the Fock-space operator formalism. The typical 3-string overlap structure as well as the correct ghost midpoint insertion are not required from the outset but arise as consequences.

The bosonic open string field theory with Wess-Zumino term

The motion space of strings is assumed as a direct product of d-dimensional Minkowski space M d with a d G -dimensional intrinsic group manifold G, M d ×G. We investigate the bosonic open string field theory with Wess-Zumino term by using the method of conformal field theory and prove the reparametrization invariance and BRST symmetry of the theory constructed. The critical dimension of Minkowski space turns out to be d = 26 − kd G/( k+ C A).

Magnetic string fields

We construct the string field in Witten's open bosonic string field theory which corresponds to a constant magnetic field. We express the answer both in the standard basis of open string modes, and in more natural basis which requires changes in the zero-zero Neumann coefficients of the three-string vertex. We discuss the feasibility of using string field theory to search for new solutions of the classical string equations.

Bosonic open-string field theory at finite temperature.

Using the methods of thermo field dynamics and conformal field theory, we have constructed the open-bosonic-string field theory with reparametrization and Becchi-Rouet-Stora-Tyutin invariances. The temperature independence of the critical dimension is also demonstrated.

Gauge fixing of open bosonic string field theory action of neveu and west

Gauge fixing of open bosonic string field theory action of neveu and west

A covariant open bosonic string field theory including the endpoint and middlepoint interaction

Extending the usual endpoint and midpoint interactions, we introduce numerous kinds of interactions, labelled by a parameter λ and obtain a non-commutative and associative string field algebra by adding up all interactions. With this algebra we develop a covariant open bosonic string field theory, which reduces to Witten's open bosonic string field theory under a special string length choice.

Combinatorics of Strings and Equivalence of Witten's String Field Theory to Polyakov's String Theory

It is shown that Polyakov's string theory and Witten's open bosonic string field theory give the same vacuum amplitudes with correct combinatorial factors in arbitrary order of perturbation expansion. The proof is based on the fact that the symmetry factor of mapping class group and the combinatorial factor of string Feynman diagram are equal. Extension to the on-shell amplitudes is also discussed.

Four-photon scattering amplitude in bosonic open string field theory

The covariant string field theory, which is formulated as a natural generalization of the light-cone gauge approach, is used to calculate three- and four-photon scattering amplitudes explicitly at tree level. The results are found to be consistent with the first quantized covariant approach.

An introduction to covariant superstring field theories

A pedagogical account is given of the recent developments in covariant (super)string field theories. After reviewing the construction of the free open bosonic string field theory, the super-symmetric case is treated and the space-time supersymmetry transformations are explained. The present status and some future problems are also summarized.

Translations as inner derivations and associativity anomalies in open string field theory

We show that spacetime translations are inner derivations of Witten's star algebra for open bosonic string field theory. The connection between inner derivations and gauge transformations is discussed. This result is in conflict with the naive expectation that the string midpoint is fixed in the star algebra. The resolution of this apparent paradox involves an anomaly in associativity. This anomaly does not appear to disturb the consistency of the theory.

Bose-Fermi equivalence in Witten's interacting string field theory

We show that the bosonic and fermionic ghost realizations of the gauge invariant open bosonic string field theory of Witten are equivalent.

A study of the vertex in Witten's string field theory

We consider Witten's formulation of the interacting open bosonic string field theory. In particular, we study the Fock space representation of the vertex, including the fields associated with the bosonized two-dimensional ghost oscillators. We calculate the vertex using conformal mapping techniques, and also via a decomposition of the constraints implied by the string overlap. The conformal mapping takes the overlap world sheet to an anticone, where the Neumann function may be found. We show how this is related to the mappings with branch cut singularities, which take this world sheet to the upper half plane.