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Nonlinear (super)symmetries and amplitudes

There is an increasing interest in nonlinear supersymmetries in cosmological model building. Independently, elegant expressions for the all-tree amplitudes in models with nonlinear symmetries, like D3 brane Dirac-Born-Infeld-Volkov-Akulov theory, were recently discovered. Using the generalized background field method we show how, in general, nonlinear symmetries of the action, ...

\( \overline{D3} \) induced geometric inflation

Effective supergravity inflationary models induced by anti-D3 brane interaction with the moduli fields in the bulk geometry have a geometric description. The Kähler function carries the complete geometric information on the theory. The non-vanishing bisectional curvature plays an important role in the construction. The new geometric formalism, with the nilpotent superfield ...

Origin of soft limits from nonlinear supersymmetry in Volkov-Akulov theory

We apply the background field technique, recently developed for a general class of nonlinear symmetries, at tree level, to the Volkov-Akulov theory with spontaneously broken \( \mathcal{N}=1 \) supersymmetry. We find that the background field expansion in terms of the free fields to the lowest order reproduces the nonlinear supersymmetry transformation rules. The double soft limit ...

Maximal supersymmetry and B-mode targets

Extending the work of Ferrara and one of the authors [1], we present dynamical cosmological models of α-attractors with plateau potentials for 3α = 1, 2, 3, 4, 5, 6, 7. These models are motivated by geometric properties of maximally supersymmetric theories: M-theory, superstring theory, and maximal N = 8 supergravity. After a consistent truncation of maximal to minimal ...

Absence of U(1) anomalous superamplitudes in \( \mathcal{N} \) ≥ 5 supergravities

We list all potential candidates for U(1) anomalous non-local 1-loop 4-point amplitudes and higher loop UV divergences in \( \mathcal{N} \) ≥ 5 supergravities. The relevant chiral superinvariants are constructed from linearized chiral superfields and define the corresponding superamplitudes. The anomalous amplitudes, of the kind present in \( \mathcal{N} \) = 4, are shown to be ...

String theory origin of constrained multiplets

We study the non-linearly realized spontaneously broken supersymmetry of the (anti-)D3-brane action in type IIB string theory. The worldvolume fields are one vector A μ , three complex scalars ϕ i and four 4d fermions λ 0, λ i. These transform, in addition to the more familiar \( \mathcal{N}=4 \) linear supersymmetry, also under 16 spontaneously broken, non-linearly realized ...

Coupling the inflationary sector to matter

We describe the coupling of matter fields to an inflationary sector of supergravity, the inflaton Φ and a stabilizer S, in models where the Kähler potential has a flat inflaton direction. Such models include, in particular, advanced versions of the hyperbolic α-attractor models with a flat inflaton direction Kähler potential, providing a good fit to the observational data. If the ...

Orthogonal nilpotent superfields from linear models

We derive supersymmetry/supergravity models with constrained orthogonal nilpotent superfields from the linear models in the formal limit where the masses of the sgoldstino, inflatino and sinflaton tend to infinity. The case where the sinflaton mass remains finite leads to a model with a ‘relaxed’ constraint, where the sinflaton remains an independent field. Our procedure is ...

String theory realizations of the nilpotent goldstino

We describe in detail how the spectrum of a single anti-D3-brane in four-dimensional orientifolded IIB string models reproduces precisely the field content of a nilpotent chiral superfield with the only physical component corresponding to the fermionic goldstino. In particular we explicitly consider a single anti-D3-brane on top of an O3-plane in warped throats, induced by (2, 1) ...

Linear versus non-linear supersymmetry, in general

We study superconformal and supergravity models with constrained superfields. The underlying version of such models with all unconstrained superfields and linearly realized supersymmetry is presented here, in addition to the physical multiplets there are Lagrange multiplier (LM) superfields. Once the equations of motion for the LM superfields are solved, some of the physical ...

Emergence of spontaneously broken supersymmetry on an anti-D3-brane in KKLT dS vacua

The KKLT construction of de Sitter vacua includes an uplifting term coming from an anti-D3-brane. Here we show how this term can arise via spontaneous breaking of supersymmetry, based on the emergence of a nilpotent chiral supermultiplet on the world-volume of the anti-D3-brane. We establish and use the fact that both the DBI as well as the WZ term, with account of orientifolding, ...

α-attractors: Planck, LHC and dark energy

We develop four-parameter supergravity models of inflation and dark energy, constrained so that \( \frac{\delta \rho }{\rho } \), n s and the cosmological constant Λ take their known observable values, but where the mass of gravitino m 3/2 and the tensor-to-scalar ratio r are free parameters. We focus on generalized cosmological α-attractor models, with logarithmic Kähler ...

Cosmological attractor models and higher curvature supergravity

Sergio Cecotti 1 Renata Kallosh 0 0 Department of Physics and SITP, Stanford University , 382 via Pueblo Mall, Stanford, California 94305, U.S.A 1 Scuola Internazionale Superiore di Studi Avanzati

Inflation, de Sitter landscape and super-Higgs effect

We continue developing cosmological models involving nilpotent chiral super-fields, which provide a simple unified description of inflation and the current acceleration of the universe in the supergravity context. We describe here a general class of models with a positive cosmological constant at the minimum of the potential, such that supersymmetry is spontaneously broken in the ...

Cosmology with nilpotent superfields

We discuss N=1 supergravity inflationary models based on two chiral multi-plets, the inflaton and the goldstino superfield. Using superconformal methods for these models, we propose to replace the unconstrained chiral goldstino multiplet by the nilpotent one associated with non-linearly realized supersymmetry of the Volkov-Akulov type. In the new cosmological models, the sgoldstino ...

The double attractor behavior of induced inflation

We describe an induced inflation, which refers to a class of inflationary models with a generalized non-minimal coupling ξg(ϕ)R and a specific scalar potential. The defining property of these models is that the scalar field takes a vev in the vacuum and thus induces an effective Planck mass. We study this model as a function of the coupling parameter ξ. At large ξ, the predictions ...

Large field inflation and double α-attractors

We consider a broad class of inflationary models that arise naturally in super-gravity. They are defined in terms of a parameter α that determines the curvature and cutoff of these models. As a function of this parameter, we exhibit that the inflationary predictions generically interpolate between two attractor points. At small cutoff α, the resulting inflationary model is of ...

Analytic classes of metastable de Sitter vacua

In this paper, we give a systematic procedure for building locally stable dS vacua in \( \mathcal{N}=1 \) supergravity models motivated by string theory. We assume that one of the superfields has a Kähler potential of no-scale type and impose a hierarchy of supersymmetry breaking conditions. In the no-scale modulus direction the supersymmetry breaking is not small, in all other ...

\( \overline{\mathrm{D}3} \) and dS

The role of the \( \overline{\mathrm{D}3} \) brane in providing de Sitter vacua with spontaneously broken supersymmetry in the KKLT construction is clarified. The first step in this direction was explained in [1, 2]: it was shown there that in the GKP background the bosonic contributions to the vacuum energy from the DBI and WZ term cancel for a D3 brane, but double for a \( ...

On the supersymmetric completion of R + R 2 gravity and cosmology

We revisit and clarify the supersymmetric versions of R + R 2 gravity, in view of the renewed interest to these models in cosmology. We emphasize that the content of the dual standard supergravity theory in the old minimal formulation necessarily includes two massive chiral multiplets, that we call the inflaton and the goldstino. We point out that the presence of these multiplets ...