Auxiliary supergravity fields,Chern-Simons terms and the heterotic string

The generating functional of target space S-matrix amplitudes is generalized to include auxiliary field and fermionic vertex operators. Using this formalism, a new Green-Schwarz mechanism associated with the auxiliary vector field of the four-dimensional, N=1 supergravity multiplet of the heterotic string is derived.     

What we learn on the heterotic string vacua from anomaly-free supergravity

The recently constructed D = 10 anomaly-free supergravity (AFS) has been argued to contain the full effective theory of the heterotic string. The solutions of the effective theory must be solutions of AFS, while the converse is not necessarily true since string theory might specify the boundary conditions for the AFS torsion equation. We show that Calabi-Yau spaces are exact solutions of AFS, while compact group and coset manifolds are not. This is due to a positivity argument, which is the extension to anomaly-free supergravity of the “ten into four won't go” theorem of Freedman, Gibbons and West for the Chapline-Manton theory.     

No renormalization of the N=1 supergravity theory derived from the heterotic string

We show that one-loop string effects do not alter the form of the leading terms in the low-energy effective ten-dimensional N=1 supergravity theory derived from the heterotic string. We extend this result to the four-dimensional N=1 supergravity theory obtained after compactification, showing in particular that its Kähler potential is not renormalized by string loop effects or by the exchange of Kaluza-Klein modes. We also demonstrate that the Kähler potential and the gauge kinetic function are not renormalized by one-loop string effects in a wide class of four-dimensional formulations of superstring theories.     

Anomaly-free supergravity theories remain anomaly-free after dimensional reduction

We show that the anomaly after compactification of a supergravity theory coupled to Yang-Mills matter is usually given by an integral of the original anomaly over the compact space, as long as there are no isometries for the compact space. This means that a supergravity theory, whose anomaly vanishes identically (i.e., without the addition of local counter terms to the action), will remain anomaly-free after compactification to any lower dimension, subject to some restrictions on self-dual antisymmetric tensors. We next consider the case where the original anomaly cancels by the Green-Schwarz mechanism. In this case, again subject to the restrictions on self-dual antisymmetric tensors, the anomaly will still cancel after compactification to any lower dimension D > 2, provided that: (1) There are no U(1) gauge groups after compactification. (2) There exists a three-form field strength H such that dH = (TrR₀² + kTrF₀²), or that the compact space is chosen such that (TrR₀² + kTrF₀²) = 0.     

Gauge field corrections to 11-dimensional supergravity via dimensional reduction

Using the fact that eleven-dimensional supergravity yields type IIA supergravity under dimensional reduction on a circle, we determine higher-derivative terms of 11-dimensional supergravity including the \( R^4 \), \( ({\partial {F_4}})^2 R^2 \) and \( ({\partial {F_4}})^4 \) terms.     

Effective supergravity for supergravity domain walls

We discuss the low energy effective action for the bosonic and fermionic zero-modes of a smooth BPS Randall–Sundrum domain wall, including the induced supergravity on the wall. The result is a pure supergravity in one lower dimension. In particular, and in contrast to non-gravitational domain walls or domain walls in a compact space, the zero-modes representing transverse fluctuations of domain wall have vanishing action.     

Little heterotic strings

We discuss toroidal orbifolds of the E ₈×E ₈ heterotic string, in which the free-fermionic Higgs–matter splitting is implemented by a shift in the internal lattice coupled with the fermion numbers of the gauge degrees of freedom. We consider models in which some choices of the orbifold result in the projection of the graviton. In the models that we consider the projection also results in flipping the spin–statistics assignments in the massive string spectrum, whereas the massless spectrum retains the conventional spin–statistics assignments. We argue that the partition functions are mathematically consistent for one- and multi-loop amplitudes, owning to the existence of supersymmetry in the spectrum. A duality between different models at non-zero temperature is briefly discussed.     

Consistent supergravity

A combined spin 2 - spin $\text{3}\text{2}$ extension of general relativity is given which is both free of the usual higher spin inconsistencies and invariant under local supersymmetry transformations.     

Structure of supergravity

It is shown how to construct actions and kinetic multiplets out of scalar multiplets of supergravity. The multiplets containing the scalar and the conformal tensor are obtained and yield the gauge actions of Einstein and Weyl supergravity. The complete supersymmetric R² and Bel-Robinson invariants are also obtained as well as general n-loop counterterms.     

Anisotropic supergravity cosmologies

Anisotropic cosmologies of Bianchi types I, II, VI₀, VII₀, VIII and IX are studied in the bosonic sector of d = 11 supergravity. Exact solutions are given for all types in s = 4 dimensions coupled to the “round” (d ? s = 7) seven-sphere solutions due to Freund, Rubin, Duff and Pope, and Englert. The generalized Kasner, the Taub-NUT-de Sitter and some “mixmaster” solutions with a cosmological constant are derived. In addition, we wish to point out that the isotropic solution given recently by Myung and Kim does not exist. Another inconsistent solution was also given by Gleiser et al.     

Anomalies in supergravity

There has been much interest recently in the problem of anomalies in field theory. This is a consequence of recent work on the regularization of stress tensors, and of renewed interest in the axial vector anomaly. In this paper, I shall present a derivation of both the trace anomaly and the axial vector anomaly for the spin-$\text{3}\text{2}$ Majorana field using a zeta function regularization procedure. This result is also of interest in supergravity and extended supergravity.