M. de Roo

Ten-dimensional Maxwell-Einstein supergravity, its currents, and the issue of its auxiliary fields

The d = 10, N = 1 Yang-Mills system is coupled to d = 10, N = 1 supergravity in a locally scale-invariant way. An analysis of the currents agrees with the Noether coupling results and reveals the existence of two ordinary axial and more low-dimension auxiliary fields. The coupling of the photon Aµ to antisymmetric tensors AµI½ is consistent because the Maxwell transformation I´Aµ = ∂µI› is extended to I´AµI½ = IoI›FµI½.

T-duality and actions for non-BPS D-branes

We employ T-duality to restrict the tachyon dependence of effective actions for non-BPS D-branes. For the Born-Infeld part the criteria of T-duality and supersymmetry are satisfied by a simple extension of the D-brane Born-Infeld action.

Extended Conformal Supergravity

Abstract We present the complete structure of extended conformal supergravity for N ⩽4. The relation with the graded algebra SU(2, 2| N ) and with the multiplet of currents is discussed. The N = 4 superconformal theory has a formulation with local SU(4)×U(1) and rigid SU(1, 1) invariance. We give the linearized invariant actions for all N . For N = 2 we exhibit the complete non-linear lagrangian.

The quartic effective action of the heterotic string and supersymmetry

We present the supersymmetric quartic effective action for the heterotic string which follows from the supersymmetrization of the Yang-Mills and Lorentz Chern-Simons forms. This includes all bosonic terms in the action, and all bosonic contributions to the supersymmetry transformation rules, thereby giving all terms to this order which are relevant for the study of compactification scenarios with unbroken supersymmetry.

Gauged matter coupling in N = 4 supergravity

Abstract Gauged N = 4 supergravity with an arbitrary number of matter multiplets is constructed from a superconformal starting point. It includes both the SO(4) and SU(4) symmetric N = 4 supergravity theories, and all their gaugings. Noncompact Yang-Mills symmetries may mix the matter and supergravity vector fields. We establish that in matter coupled N = 4 supergravity theories the super-Higgs effect can occur with a vanishing cosmological constant. An example is given with gauged SO(3) × SO(2, 1) symmetry in which the scalar potential vanishes completely, and all four supersymmetries are broken.

Matter coupling in N = 4 supergravity☆

Abstract An arbitrary number of abelian vector multiplets is coupled to N = 4 supergravity. The resulting action is invariant under global SO( n ,6), where n is the number of vector multiplets, and under local SU(4)×U(1) transformations. The scalar fields of the theory parametrize the manifold [SO( n ,6)/SO( n )×SO(6)]×[SU(1,1)/U(1)]. The role of the matter fields of the N = 4 Weyl multiplet in the Poincare supergravity theory is clarified.

D-branes and T-duality

Abstract We show how the T-duality between D-branes is realized (i) on p-brane solutions (p = 0,…,9) of IIA IIB supergravity and (ii) on the D-brane actions (p = 0,…, 3) that act as source terms for the p-brane solutions. We point out that the presence of a cosmological constant in the IIA theory leads, by the requirement of gauge invariance, to a topological mass term for the worldvolume gauge field in the 2-brane case.

Supersymmetric non-abelian Born-Infeld revisited

We determine the non-abelian Born-Infeld action, including fermions, as it results from the four-point tree-level open superstring scattering amplitudes at order 02 . Wend that,after anappropriateeld redenition allterms at this order canbewrittenasasymmetrised trace. Weconfront thisactionwiththeresultsthat follow from kappa-symmetry and conclude that the recently proposed non-abelian kappa-symmetry cannot be extended to cubic orders in the Born-Infeld curvature.

IIA Ten-forms and the Gauge Algebras of Maximal Supergravity Theories

We show that IIA supergravity can be extended with two independent 10-form potentials. These give rise to a single BPS IIA 9-brane. We investigate the bosonic gauge algebra of both IIA and IIB supergravity in the presence of 10-form potentials and point out an intriguing relation with the symmetry algebra E11, which has been conjectured to be the underlying symmetry of string theory/M-theory.

Conformal supergravity in ten dimensions

Abstract We present the complete off-shell structure of conformal supergravity in ten dimensions. It is based on 128 + 128 degrees of freedom and its formulation requires differential constraints. We study how these constraints are resolved in four and five dimensions. Covariant conditions are given that restrict conformal supergravity to its on-shell Poincare counterpart. In ten dimensions the relationship between the two theories has new and unusual aspects, which we explore in a variety of ways. We rewrite on-shell Poincare supergravity in a superconformally invariant form, from which we deduce that its off-shell version must contain at least a scalar (chiral) multiplet. We analyze some aspects of the non-linear structure of the field representation based on the conformal fields combined with one scalar multiplet.