arXiv subjects

Sylvain Thomée

Publications and source records attributed to Sylvain Thomée.

4 recordsLinked to original sources

arXiv2026

The complete action for $\mathcal{N}=2$ de Sitter pure supergravity

Supergravity theories in de Sitter spacetime are known to be very constrained, and rather unnatural within String/M Theory. We revisit the seminal paper by Pilch, van Nieuwenhuizen and Sohnius, where the possible existence of a real Lagrangian for ${\cal N}=2$ pure supergravity in four-dimensional de Sitter spacetime was pointed out. We clarify several issues related to the non-unitarity of the theory and explicitly construct the unique, complete theory searched for long ago by the aforementioned authors. We argue that the lack of unitarity of the Lorentzian theory may be revisited in the Euclidean approach to de Sitter quantum gravity, where alternative definitions of unitarity can be introduced.

hep-th↗

arXiv2025

A note on partially massless supergravity

We analyse the couplings of a partially massless spin-2 field with a doublet of massless, real spin-3/2 fields. In the flat limit, this spectrum coincides with the spectrum of ${\cal N}=2$ pure supergravity around anti-de Sitter spacetime AdS$_4$. We classify all the possible parity-invariant, non-Abelian deformations of the free theory that lead to a deformation of the Lagrangian. By doing this, we re-derive a non-Abelian vertex recently found in 2412.04982 [hep-th] by Yu. M. Zinoviev following a different approach, and show that the corresponding non-Abelian gauge algebra closely resembles the one of ${\cal N}=2$ supergravity around AdS$_4$. The gauge-algebra deformation is however obstructed, at next order. Then, we add a massless vector field together with a massive spin-3/2 field, and find two nontrivial vertices mixing these fields with a single massless gravitino. Still, the gauge algebra remains obstructed at next order, therefore excluding the possibility to make local the global supersymmetry algebra found in recent works on partially massless supermultiplets in AdS$_4$. Finally, we argue that the two problems encountered are simultaneously solved by the addition of the masseless graviton, leading to ${\cal N}=1$ pure conformal supergravity around AdS$_4$ as the only consistent theory coupling partially massless spin-2 fields to massless and massive spin-3/2 fields.

hep-th↗

arXiv2023

Consistent couplings between a massive spin-3/2 field and a partially massless spin-2 field

We revisit the problem of constructing consistent interactions between a massive spin-3/2 field and a partially massless graviton in four-dimensional (A)dS spacetime. We use the Stueckelberg formulation of the action principle for these fields and find two non-trivial cubic vertices with less than two derivatives, when going to the unitary gauge. One of the vertices is reminiscent of the minimal coupling of the massive spin-3/2 field to gravity, except that now the graviton is partially massless.

hep-th↗

arXiv2022

Revisiting Dudas-Mourad compactifications

Superstring theories in ten dimensions allow spacetime supersymmetry breaking at the string scale at the expense of controlled Minkowski backgrounds. The next-to-maximally symmetric backgrounds, found by Dudas and Mourad, involve a warped compactification on an interval associated with codimension-one defects. We generalize these solutions by varying the effective field theory parameters, and we discuss the dimensional reduction on the interval. In particular, we show that scalars and form fields decouple in a certain range of dimensions, yielding Einstein-Yang-Mills theory. Moreover, we find that the breakdown of this effective description due to light Kaluza-Klein modes reflects the swampland distance conjecture, supporting the consistency of the picture at least qualitatively.

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