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Fotis Farakos

Publications and source records attributed to Fotis Farakos.

At least 19 recordsLinked to original sources
arXiv2026

Scale-separated vacua with extended supersymmetry

We propose the first examples of scale-separated vacua with extended supersymmetry. They arise as circle compactifications of four-dimensional vacua of massive type IIA supergravity with scale separation, upon introducing additional fluxes and sources. We provide both the ten-dimensional solutions and the three-dimensional effective descriptions in terms of K\"ahler potential and superpotential. The conformal dimensions of the putative dual two-dimensional field theory appear not to be integers. The superpotential for the additional fluxes of one of our models was guessed by ChatGPT and, to the best of our knowledge, it does not appear in existing literature. Should these vacua be solutions of string theory, they would allow to address the open problem of scale separation from the vantage point of extended supersymmetry.

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arXiv2025

Super Yang-Mills with partially non-linear extended supersymmetry

We discuss 4D N=2 non-abelian gauge theories where one supersymmetry is preserved while the other one is spontaneously broken and non-linearly realized. The goldstino resides in a Maxwell multiplet of the Bagger-Galperin type. We introduce appropriate constraints that eliminate the chiral N=1 superfield sector of the non-abelian N=2 multiplets and discuss the properties of the leading order Lagrangians.

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arXiv2025

Warped G2 throats from deformed conifolds in IIA supergravity

We analyze the IIA supergravity solutions corresponding to a warped product of a 3D external Minkowski space and a 7D internal non-compact space, with the latter being the direct product of a deformed conifold and a circle. The specific construction allows for the presence of either a finite 4-cycle or a 3-cycle at the tip supported by the $F_4$ or the $H_3$ flux respectively. Once we mod-out by a $Z_2$ involution we can also get a G2 space, and for completeness we also report on some basic features that we expect from the embedding in a compact setup.

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arXiv2025

Warped G$_2$-throats in IIA and uplift dSillusions

Flux compactifications of IIA supergravity on orientifolded G$_2$-manifolds have been argued to allow for classical Minkowski$_3$ vacua with moduli and scale-separated AdS$_3$ vacua with full moduli stabilisation. To further uplift these vacua to meta-stable dS$_3$ vacua using anti-D2 branes, warped throats are desirable. We study the flux-stabilisation of local "CGLP-type" throats in compact G$_2$ spaces, and discuss consistency constraints on anti-brane uplifting. Despite the classical AdS$_3$ vacua to be free of tachyons, we find that uplifting from anti-branes down warped throats is forbidden. If instead we rely on hypothetical AdS$_3$ vacua that arise from quantum corrections to the classical Minkowski$_3$ vacua, we find that (similarly to the 4d analogues) consistency constraints point in opposite directions. However, there is potentially an advantage over 4d when it comes to concrete fine-tuning freedom of numbers, such as tadpole constraints.

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arXiv2025

Integer dual dimensions in scale-separated AdS$_3$ from massive IIA

We study supersymmetric scale-separated AdS$_3$ flux vacua of massive IIA on G2 orbifolds with smeared orientifold planes. We consider two types of $T^7/Z_2^3$ orbifolds which, with appropriate flux choices, yield integer dual dimensions for the operators corresponding to the closed string scalar fields in the dual CFT. As with all other known examples, the dual conformal dimensions are only parametrically close to integer values.

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arXiv2024

On Global Symmetries and Fayet-Iliopoulos Terms

We revisit the genuine Fayet-Iliopoulos terms of 4D N=1 supergravity. Such terms are commonly believed to preserve a global symmetry, and therefore they are in conflict with the principles of quantum gravity. However, we find that generically there do exist supersymmetric terms that break explicitly the specific global symmetry, while preserving gauge invariance. We illustrate this, by providing a series of examples, including superpotentials and superspace higher order terms, along with a general prescription for their construction.

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arXiv2023

Scale-separated AdS$_3\times$S$^1$ vacua from IIA orientifolds

We study supersymmetric AdS$_3$ flux vacua of massive type-IIA supergravity on anisotropic G2 orientifolds. Depending on the value of the $F_4$ flux the seven-dimensional compact space can either have six small and one large dimension such that the external space is scale-separated and effectively four-dimensional, or all seven compact dimensions small and parametrically scale-separated from the three external ones. Within this setup we also discuss the Distance Conjecture (including appropriate D4-branes), and highlight that such vacua provide a non-trivial example of the so-called Strong Spin-2 Conjecture.

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arXiv2023

On/off scale separation

We discuss minimally supersymmetric AdS$_3$ flux vacua of massive type IIA supergravity on G2-orientifolds. We find that configurations that are scale-separated can be within finite distance from non scale-separated ones, while both remain at large volume, weak coupling and have moduli stabilization. The transition is achieved with the use of a D4-brane modulus, which allows the $F_4$ flux to jump, and has an effective potential always accessible to the three-dimensional low-energy theory. Our analysis further allows us to check the distance conjecture quantitatively, as we can track explicitly the masses of the KK modes.

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arXiv2023

Supergravity EFTs and swampland constraints

In these proceedings, we review recent progress in analyzing the behavior of lower-dimensional supergravity theories when combined with swampland conjectures. We show that within supergravity the effectiveness and usefulness of swampland conjectures gets amplified, existing criteria can be intertwined and also new ones can be uncovered. Furthermore, we elaborate on some previously unpublished work. This includes evidence for the possible existence of a novel conjecture on Yukawa couplings and an argument to constrain large classes of D-term inflationary models using known conjectures.

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arXiv2023

Is Gauge Mediation in the Swampland?

We note that the typical gauge mediation of supersymmetry breaking is in tension with the global limit of the festina lente swampland bound. The alternatives are mediation/breaking schemes that decouple together with gravity, as for example gravity mediation, for which we highlight some basic phenomenological properties. Gauge mediation remains instead a viable mechanism only in models where supersymmetry is restored in the global limit, as for example in no-scale supergravity.

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arXiv2023

Goldstino condensation at large N

We analyze the standard fermionic 4D Volkov-Akulov action with N global non-linear supersymmetries. We find that the stationary points of the system are described by an effective potential, written in terms of two composite real scalar fields, which approaches the exact quantum effective potential in the large N limit. We identify the existence of at least two stationary points, one representing the original supersymmetry breaking configuration and the other one corresponding to goldstino condensation, where supersymmetry is restored in the deep IR.

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arXiv2022

Anti-brane uplift instability from goldstino condensation

We investigate the possible appearance of composite states of the goldstino in models with four-dimensional non-linear supersymmetry and we provide a description of their dynamics in terms of a Kähler potential and a superpotential. Our analysis shows that the critical point corresponding to the Volkov-Akulov model is unstable. Similarly, we find that the uplifted stable de Sitter critical point of the KKLT model is shifted and acquires a tachyonic instability. Our findings indicate the existence of a potentially dangerous instability shared by all anti-brane uplifts.

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arXiv2022

O6-plane backreaction on scale-separated Type IIA AdS$_3$ vacua

We evaluate the backreaction of O6-planes in scale-separated $\text{AdS}_3$ flux vacua of massive Type IIA. Using the appropriate flux scaling we show that the corrections to the various background fields and moduli are controlled and subleading when going from smeared to localized sources. Similarly, the backreaction corrections to the scalar potential are parametrically small in the scale-separation limit, assuming always that the near-O6-plane singularities will find a resolution within string theory, even in the presence of a Romans mass. Our analysis is based on the equations of motion and therefore applies also to the non-supersymmetric vacua.

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arXiv2021

Complex Linear Multiplets and Local Supersymmetry Breaking

We study supersymmetry breaking from a complex linear superfield coupled to 4D N=1 supergravity. The theory has two classically decoupled vacua, one supersymmetric and one with broken and intrinsically non-linear supersymmetry. Depending on the values of the parameters the scalar potential can lead to no-scale Minkwoski or a stable de Sitter or anti-de Sitter vacuum. We also provide a dual description of the system in terms of a nilpotent chiral superfield and a standard chiral coupled to supergravity.

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arXiv2021

The unbearable lightness of charged gravitini

We prove that charged gravitini cannot have parametrically small or vanishing Lagrangian mass in de Sitter vacua of extended supergravity while respecting the magnetic weak gravity conjecture. This places large classes of de Sitter solutions of gauged supergravity in the swampland, including all known stable solutions of the N=2 theory. We illustrate this result by analyzing a variety of de Sitter critical points of N=2 matter-coupled supergravity that also include new stable de Sitter solutions. Our results provide concrete evidence that (quasi) de Sitter with charged light gravitini should belong to the swampland, which also strongly resonates with the festina lente bound.

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arXiv2021

Three-dimensional flux vacua from IIB on co-calibrated G2 orientifolds

We derive the 3D N=1 superpotential for the closed string sector of type IIB supergravity on toroidal O5 orientifolds with co-calibrated G2 structure and RR background flux. We find that such compactifications can provide full closed string moduli stabilization on supersymmetric AdS$_3$ vacua, and once we include brane-supersymmetry-breaking we also find indication for the existence of classical 3D de Sitter solutions. The latter however are rather difficult to reconcile with the shape moduli stabilization and flux quantization. We also discuss the possibility of achieving scale separation in AdS$_3$ and dS$_3$ vacua, but such effects seems to be hindered by the geometric flux quantization.

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arXiv2021

de Sitter decay through goldstino evaporation

We study supergravity theories with supersymmetry intrinsically non-linearly realized supported only by four-form flux. We demonstrate that supersymmetry can be restored by the evaporation of the goldstino multiplet. Such procedure requires the existence of a super-extremal 2-brane, in accordance with the WGC, and suggests an imminent decay in de Sitter supergravity, leaving the system to relax in supersymmetric AdS after the transition. In particular, the same decay mechanism also implies that the KKLT de Sitter vacua are short-lived. Our findings thus provide an effective realization of KPV-type of decays within 4D supergravity and in this way may reconcile the nilpotent superfield constructions of de Sitter with some aspects of the swampland program.

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