37 research outputs found
Interactions of N Goldstini in Superspace
We study field theories with N extended non-linearly realized
supersymmetries, describing the couplings of models that contain N goldstini.
We review all the known formulations of the N=1 goldstino theories and we
generalize them to an arbitrary number N of non-linearly realized
supersymmetries. We explicitly prove the equivalence of all these extended
supersymmetry breaking models containing N goldstini and reformulate the theory
with N supersymmetries in terms of standard N=1 constrained superfields.Comment: 29 pages, 1 table. v2: published version. Title changed, a reference
and some comments adde
Weak gravity versus de Sitter
We show that one can uncover a Dine-Seiberg problem for de Sitter critical
points in supergravity theories by utilizing the magnetic weak gravity
conjecture. We present a large variety of N=2 gauged supergravity models that
include vector multiplets and in all cases we find that the weak gravity
conjecture threatens de Sitter. A common feature in all such examples is a
degenerate mass matrix for the gravitini, which we therefore deem a swampland
criterion for de Sitter critical points.Comment: 29 pages. v2: minor corrections and references added. Published on
JHE
Constrained superfields on metastable anti-D3-branes
We study the effect of brane polarization on the supersymmetry
transformations of probe anti-D3-branes at the tip of a Klebanov-Strassler
throat geometry. As is well known, the probe branes can polarize into
NS5-branes and decay to a supersymmetric state by brane-flux annihilation. The
effective potential has a metastable minimum as long as the number of
anti-D3-branes is small compared to the number of flux quanta. We study the
reduced four-dimensional effective NS5-brane theory and show that in the
metastable minimum supersymmetry is non-linearly realized to leading order, as
expected for spontaneously broken supersymmetry. However, a strict decoupling
limit of the higher order corrections in terms of a standard nilpotent
superfield does not seem to exist. We comment on the possible implications of
these results for more general low-energy effective descriptions of inflation
or de Sitter vacua.Comment: 22 pages, 1 figure. v2: fixed typos, matches published versio
Weak gravity versus scale separation
We give evidence that fully supersymmetric Anti-de Sitter vacua of extended supergravity with a residual gauge group containing an abelian factor cannot be scale separated as a consequence of the weak gravity conjecture. We prove this for N = 2 and N = 8 supergravity and we explain how our argument applies also to vacua with partially broken, but extended residual supersymmetry. We finally discuss possible loopholes and especially how certain N = 1 models can evade our reasoning. Our results suggest that N = 0,1 supersymmetry at the lagrangian level might be the most promising chances to obtain a truly four-dimensional effective description of quantum gravity
From linear to non-linear SUSY and back again
Abstract We show that couplings of the goldstino field, appearing when global supersymmetry is broken, can always be described in superspace by means of a nilpotent chiral superfield X, satisfying X 2 = 0. This applies to both F-term and D-term supersymmetry breaking, even when the supersymmetry breaking model admits a linear description
The Gravitino and the Swampland
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
Minimal constrained supergravity
We describe minimal supergravity models where supersymmetry is non-linearly realized via constrained superfields. We show that the resulting actions differ from the so called “de Sitter” supergravities because we consider constraints eliminating directly the auxiliary fields of the gravity multiplet