Heterotic superstrings in auxiliary field background and extended spacetime supersymmetry

We introduce the superstring vertices of the auxiliary connections of extended supergravity and elucidate the relation between the internal symmetry of the spacetime superconformal algebra and the Kac-Moody symmetry of the 2D superconformal algebra. The microscopic computation of effective lagrangians is outlined: it turns out that the low-energy effective lagrangians for 4D heterotic superstrings are of a standard supergravity form.     

Quantum field theory in curved spacetime

Quantum field theory predicts a number of unusual physical effects in non-Minkowskian manifolds (flat or curved) that have no immediate analogs in Minkowski spacetime. The following examples are reviewed: (1) The Casimir effect; (2) Radiation from accelerating conductors; (3) Particle production in manifolds with horizons, including both stationary black holes and black holes formed by collapse. In the latter examples curvature couples directly to matter through the stress tensor and induces the creation of real particles. However, it also induces serious divergences in the vacuum stress. These divergences are analyzed, and methods for handling them are reviewed.     

Space-time supersymmetry in covariant superstring field theory

It is shown that the existence of a transition operator, which interchanges the BRS charges of the Neveu-Schwarz and the Ramond sectors, implies space-time supersymmetry in the covariant free open superstring field theory proposed previously by the present authors.     

String field theory in curved space

The purely cubic action in the string field theory is shown to provide a set of equations of motion for background fields which agree to those obtained by the vanishing condition of ß-functions in the non-linear sigma model. Using the sigma model as an auxiliary tool, a systematic method for solving the string field theory in curved space is proposed.     

String field theory and infinite grassmannian

An interesting connection between Witten's string field theory and the infinite grassmannian, and the possible characterization of the group orbit on the grassmannian by the bilinear identity are examined.     

The spontaneously broken supersymmetry in quantum field theory

It is shown that every spontaneous breaking of supersymmetry can be accomplished by means of a locally conserved supercurrent

$\text{εαβf}{}^{\mathrm{+}}{}_{\mathrm{<mtext>\gamma </mtext><mtext>?</mtext>}}\text{, α, β, γ = 1, 2,}$

$\text{εαβ =}\text{0}\text{1}\text{?1}\text{1}$

, where $\text{f}{}^{\mathrm{+}}{}_{\mathrm{<mtext>\gamma </mtext><mtext>?</mtext>}}$ is a massless field satisfying the Weyl Equation. For a given supercurrent $\text{jαβ}\text{γ}\text{?}$ the necessary condition that it will break spontaneously the supersymmetry is

$\text{jαβ}\text{γ}\text{?}\text{?jβα}\text{γ}\text{?}\text{≠0.}$

It is shown that the anticommutation relations of the broken supercharges are not related to the energy-momentum vector.Similar procedure applied in case of a vector field is inconclusive.The extension of the Maisson and Reeh statement on the helicity of Goldstone fields is given.     

Assignments in strong-electroweak unified models with internal and spacetime supersymmetry

We present a candidate model based upon the supergroup SU(5/1) as a possible unified gauge theory of the strong and electroweak interactions, having a natural SU (2/1)_flavour×SU (3)_colour subgroup structure. Young diagram and superfield techniques are introduced for handling irreducible representations of the classical supergroups.     

Group-renormalization approach in quantum field theory in curved spacetime with torsion

The nature of the interaction of the gauge models SU(N) and O(N) with an external torsion field is studied from the group-renormalization point of view. Consideration of the radiation corrections to the nonminimal interaction gives a possible explanation for the absence of a torsion field in observational data.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 34–38, October, 1990.The authors thank I. L. Buchbinder for discussion of the work.     

String length and covariant string field theory

String length differentials are shown to arise naturally in a BRST hamiltonian approach to the closed bosonic string. A gauge-covariant quadratic action is proposed which is shown to lead to the correct equations of motion. The gauge covariant action is extended to including a three-string interaction vertex, with exact invariance under an extended transformation on the string fields.     

String field theory in the Siegel gauge

We specialize the gauge-fixing procedure for the Witten action of the open bosonic string, given in a preceding paper, choosing the Siegel gauge. We find that the BRST-invariant gauge-fixed action is the gauge invariant one with ghost number unrestricted plus a gauge-fixing term. The BRST invariance of the measure in the functional integral is briefly discussed. As a technical tool the Hodge dual of a string functional is defined.     

Toward a string field theory independent of spacetime topology

We discuss the structure of the infinite-dimensional space which forms the domain of the string field. It is shown that this space is independent of the dimension of spacetime M and depends at most weakly on other topological properties of M. This suggests a formulation of string field theory which is (formally) completely independent of spacetime.     

Translation gauge field theory of gravity in Minkowski spacetime

The gravitational field h_μυ with spin-2 is introduced naturally by the requirement that the Lagrangian is locally translation invariant in Minkowski spacetime.The interactions between the h_μυ and spin-1/2,0,1 matter fields are obtained along with the Lagrangian for the gravitational field including self-interactions.The deflection angle of light when it passes through the sun is calculated with different gauge conditions as an example.Our leading-order result is the same as...     

Spectral asymmetry and quantum field theory in curved spacetime

I discuss cosmological particle production in spaces with spectral asymmetry. A change in the amount of spectral symmetry sufficient to produce a level crossing will result in the creation of neutrino pairs rather than neutrino, antineutrino pairs; the net excess of fermions being given by the number of level crossing. A symmetric Bianchi IX model is treated in detail and for large initial anisotropy the number of neutrinos produced is ($\text{1}\text{256}$) exp 12β₊ where β₊ is a measure of the initial anisotropy. The relation of this phenomenon to chiral anomalies and to the Atiyah-Patodi-Singer index theorem for manifolds with boundary is described. The effect of spectral asymmetry on photons is discussed and it is shewn that no level crossing can occur.     

String cosmology and the dimension of spacetime

The implications of string theory for understanding the dimension of uncompactified spacetime are investigated. Using recent ideas in string cosmology, a new model is proposed to explain why three spatial dimensions grew large. Unlike the original work of Brandenberger and Vafa, this paradigm uses the theory of random walks. A computer model is developed to test the implications of this new approach. It is found that a four-dimensional spacetime can be explained by the proper choice of initial conditions.     

String cosmology in inhomogeneous cylindrically symmetric spacetime

String-dust cosmology in an inhomogeneous cylindrically symmetric model is considered. Solutions are obtained only for geometric string with the separability assumption for metric coefficients.