Supersymmetric Horizons at the Edge of Effective Field Theory

TL;DR

This paper introduces the Supersymmetric Horizon Stabilization framework, unifying early universe inflation, metastable acceleration, and supersymmetric endpoints within supergravity, with implications for the Swampland conjectures and primordial black hole production.

Contribution

It presents a novel supergravity-based framework connecting inflation, metastability, and supersymmetry at cosmic boundaries, with new insights into moduli stabilization and Swampland conditions.

Findings

Models exhibit exponential scalar field profiles allowing trans-Planckian excursions.

Framework avoids light towers of states, consistent with Swampland conjectures.

Supports primordial black hole formation through transient scalar fluctuation enhancements.

Abstract

What if supersymmetry is not something to be hidden, but something to be reached? We introduce the Supersymmetric Horizon Stabilization (SHS): a conceptually unified and analytically controlled framework for embedding metastable de Sitter vacua and trans-Planckian inflation within effective $\mathcal{N}=1$ supergravity. Built from a logarithmic K\"ahler potential modified by nilpotent constraints, SHS yields a framework that connects the early universe's inflationary phase, intermediate metastable acceleration, and a final supersymmetric fixed point. We classify viable models by enforcing four essential criteria: absence of ghosts, de Sitter metastability, smooth Minkowski transitions, and asymptotic supersymmetry. The resulting scalar dynamics exhibit exponential field-space profiles, $\tau(\varphi) \sim e^{-\Delta\varphi}$, allowing trans-Planckian excursions with bounded moduli. This structure leads to finite geodesic distance and a stabilized gravitino mass, conditionally avoiding towers of light states and remaining consistent with the Gravitino and Swampland Distance Conjectures. At the same time, the divergent Euclidean cost of reaching the supersymmetric endpoint realizes the AdS and Generalized Swampland Distance Conjectures, situating the infrared boundary at infinite dynamical distance. From this behavior emerges the Supersymmetric Horizon Conjecture: that consistent gravitational EFTs may begin and end with supersymmetry -- both at the origin and the asymptotic edge of cosmic evolution -- not as a fine-tuned remnant, but as a geometric boundary condition. SHS also supports localized features that transiently enhance scalar fluctuations, enabling efficient production of primordial black holes with masses far exceeding those in conventional inflationary scenarios.