74 research outputs found
Constrained superfields in Supergravity
We analyze constrained superfields in supergravity. We investigate the
consistency and solve all known constraints, presenting a new class that may
have interesting applications in the construction of inflationary models. We
provide the superspace Lagrangians for minimal supergravity models based on
them and write the corresponding theories in component form using a simplifying
gauge for the goldstino couplings.Comment: 24 pages. v2: JHEP final version (fixed typos, references added
Updates in local supersymmmetry and its spontaneous breaking
We give a basic review of some recent developments in local supersymmetry
breaking in 4-dimensional effective theories coming from compactifications of
string and M-theory in the presence of non-trivial form and geometrical fluxes.Comment: Contribution to the Proceedings of the 43rd Erice International
School of Subnuclear Physics 200
A new class of N=1 no-scale supergravity models
We introduce a new N=1 no-scale supergravity model with F- and D-term
breaking. It contains a single chiral supermultiplet T and a single U(1) vector
multiplet U, gauging an axionic shift symmetry. Both supersymmetry and the
gauge symmetry are spontaneously broken, with the spin-3/2, spin-1 and spin-1/2
masses sliding along a classical flat direction, with a single real massless
scalar in the spectrum. The other degrees of freedom are absorbed by the
massive gravitino and vector. We extend our model, under very mild conditions,
to general gauge groups and matter content.Comment: 4 pages, RevTeX. Version to be published in PR
On sgoldstino-less supergravity models of inflation
We go a step further in the search for a consistent and realistic
supergravity model of large-field inflation by building a class of models with
the following features: during slow-roll, all the scalar fields other than the
inflaton are frozen by large inflaton-dependent masses or removed from the
spectrum; at the end of inflation, supersymmetry is spontaneously broken with
naturally vanishing classical vacuum energy. We achieve this by combining some
geometrical properties of the Kaehler potential with the consistent use of a
single nilpotent chiral superfield, in one-to-one correspondence with the
supersymmetry-breaking direction in field space at the vacuum.Comment: 19 pages. v2: references added and few minor changes to the text. v3:
published versio
N = 1, D = 6 Supergravity: Duality and non Minimal Couplings
In this paper we present a superspace formulation of
supergravity with one tensor-multiplet and an arbitrary number of vector- and
hypermultiplets, in which the bosonic abelian superforms of the theory, the
dilaton, the abelian gauge fields and the two-form are replaced by their
S-duals i.e. four, three and two-superforms respectively, in compatibility with
supersymmetry. As usual this replacement interchanges Bianchi identities with
equations of motion. This formulation holds in the presence of one tensor
multiplet and arbitrary numbers of hypermultiplets and abelian super-Maxwell
multiplets if all couplings are minimal. We determine the consistency
conditions for non-minimal couplings in , supergravity, for
which we present a particularly significant solution, namely the one associated
with the Chern-Simons-Lorentz three-form which entails the Green-Schwarz
anomaly cancellation mechanism. In the case of non minimal couplings it is
found that the gauge fields and the two-form can still be dualized while the
dilaton has to remain a zero-form.Comment: LaTeX2e file, 29 pages, uses package latexsym, no figure
Quantum corrections to broken N = 8 supergravity
We show that the one-loop effective potential of spontaneously broken N=8
supergravity is calculable and finite at all classical four-dimensional
Minkowski vacua without tachyons in the spectrum. The reason is that the
supertraces of the quadratic and quartic mass matrices vanish along the
classically flat directions: Str M^2 = Str M^4 =0. We also show that Str M^6 =
0 but Str M^8 > 0 in a broad class of vacua with broken supersymmetry on a flat
background, which includes all those explicitly identified so far. We find
analytical and numerical evidence that the corresponding one-loop effective
potential is negative-definite.Comment: 30 pages. v2: few misprints corrected. v3: JHEP published versio
Gauged supergravity algebras from twisted tori compactifications with fluxes
Using the equivalence between Scherk-Schwarz reductions and twisted tori
compactifications, we discuss the effective theories obtained by this procedure
from M-theory and N =4 type II orientifold constructions with Neveu-Schwarz and
Ramond-Ramond form fluxes turned on. We derive the gauge algebras of the
effective theories describing their general features, in particular the
symplectic embedding in the duality symmetries of the theory. The generic gauge
theory is non-abelian and its gauge group is given by the semidirect product of
subgroups of SL(7) or SL(p-3) x SL(9-p) for p=3,...,9, with generators
describing nilpotent subalgebras of e_{7(7)} or so(6,6) (in M and type II
theories respectively).Comment: Latex, 23 pages. v2 Comments and references added, section 2
expanded. v3 typos corrected, final version to appear in Nucl. Phys.
Chromo-Natural inflation in Supergravity
We present supergravity realizations of chromo-natural inflationary models.
We show that by using superpotentials with "imaginary" holomorphic functions of
the inflaton one can obtain effective theories of inflation that are also
consistent truncations of the original supergravity models.Comment: 5 pages. v2: References added, consistent truncation clarified and
added a paragraph on non-linear realization
Minimal scalar-less matter-coupled supergravity
We build the minimal supergravity model where the nilpotent chiral goldstino
superfield is coupled to a chiral matter superfield, realising a different
non-linear representation through a mixed nilpotency constraint. The model
describes the spontaneous breaking of local supersymmetry in the presence of a
generically massive Majorana fermion, but in the absence of elementary scalars.
The sign and the size of the cosmological constant, the spectrum and the
four-fermion interactions are controlled by suitable parameters.Comment: 8 page
Uplifts of maximal supergravities and transitions to non-geometric vacua
We describe a new procedure to obtain consistent backgrounds that uplift
vacua and deformations of various maximal gauged supergravities by taking a
known solution and performing singular limits along the moduli space of the
corresponding 4-dimensional theory. We then apply this procedure to the S^3 x
H^{2,2} background that provides the uplift of 4-dimensional Minkowski vacua of
maximal supergravity with gauge group [SO(4) x SO(2,2)] R^{16}. We
find that the newly generated vacua are generally only locally geometric and
correspond to asymmetric orbifolds, Q-flux backgrounds or combinations thereof.
We also provide the uplift to eleven dimensions of all the four-parameter
Cremmer-Scherk-Schwarz gaugings.Comment: 46 pages. Various minor text addition
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