The gravitino and the swampland

Abstract

We propose a new swampland conjecture stating that the limit of vanishing gravitino mass corresponds to the massless limit of an infinite tower of states and to the consequent breakdown of the effective field theory. We test our proposal in large classes of models coming from compactification of string theory to four dimensions, where we identify the Kaluza-Klein nature of the tower of states becoming light. We point out a general relation between the gravitino mass and abelian gauge coupling in models with extended supersymmetry, which can survive also in examples with minimal supersymmetry. This allows us to connect our conjecture to other well established swampland conjectures, such as the weak gravity conjecture or the absence of global symmetries in quantum gravity. We discuss phenomenological implications of our conjecture in (quasi-)de Sitter backgrounds and extract a lower bound for the gravitino mass in terms of the Hubble parameter.

The unbearable lightness of charged gravitini

“…Our analysis also makes contact with recent work [18,19] claiming that the massless gravitini limit would correspond to a parametrically low cut-off due to towers of light states entering the EFT. Our work here and the earlier work [12] is in agreement with these conjectures as the de Sitter points with vanishing gravitino mass are proposed to be in the swampland precisely because of a very low cut-off, and thus, clearly, so is the limit when approaching such points.…”

“…Conversely, our findings can be interpreted as a highly non-trivial check on the consistency of the FL bound, by simply applying it on the N=2 gravitini and demanding gravity to be the weakest force. Complementary arguments, that deal with the lowering of the EFT cut-off in the limit of light gravitini, including considerations based on the WGC, appear in [18], and are further established in [19]. 2 For completeness, let us note that further restrictions on the properties of scalar potentials such that gravity remains the weakest force have been considered in [24][25][26], while the WGC in de Sitter space has been further studied in [27,28].…”

Dynamical Cobordism and Swampland Distance Conjectures

“…• The ADC-like scaling may also signal some potential interplay with the Gravitino Distance Conjecture [50,51]. One expects to find a power relation between the mass of the gravitino and the scalar curvature of the solution, it would be certainly interesting to test this and to look for some pattern in the corresponding powers.…”

Supersymmetry breaking, brane dynamics and Swampland conjectures

“…Within the scope of this paper, the former setting comprise the SO(16) × SO (16) heterotic model of [1,2] and the U(32) "type 0 B" model of [3,4], while the latter setting is embodied by the USp(32) model of [5], which exhibits the peculiar phenomenon of "brane supersymmetry breaking" (BSB) [6][7][8][9]. 1 The notion that high-energy supersymmetry breaking is in some sense natural also resonates with recent considerations stemming from the Swampland program [11,12], and in particular the central role played by the gravitino mass is suggestively reminiscent of BSB, as discussed in [10].…”

“…heterotic model, while an analogous solution describing extremal D5-branes is still lacking and presents some subtleties. 11 Although the internal sphere ought to reflect the simplest setting of parallel branes in the vacuum, it brings along perturbative instabilities [49]. Since eq.…”