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The Eisenhart lift allows formulating the dynamics of a scalar field in a potential as pure geodesic motion in a curved field-space manifold involving an additional fictitious vector field. Making use of the formalism in the context of inflation, we show that the main inflationary observables can be expressed in terms of the geometrical properties of a two-dimensional uplifted field-space manifold spanned by the time derivatives of the scalar and the temporal component of the vector. This allows to abstract from specific potentials and models and describe inflation solely in terms of the flow of geometric quantities. Our findings are illustrated through several inflationary examples previously considered in the literature.

It has been argued that oscillatory features from spectator fields in the primordial power spectrum could be a probe of alternatives to inflation. In this work, we soften this claim by showing that the frequency and amplitude dependence of the patterns appearing in these scenarios could be mimicked by field interactions during inflation. The degeneracy of the frequency holds for the n-point correlation functions, while the degeneracy of the amplitude is broken at the level of non-gaussianities. Keywords: Inflation, Early universe, Primordial features, Primordial standard clocks, Alternatives to inflation

We point out that the successful generation of the electroweak scale via gravitational instanton configurations in certain scalar-tensor theories can be viewed as the aftermath of a simple requirement: the existence of a quadratic pole with a sufficiently small residue in the Einstein-frame kinetic term for the Higgs field. In some cases, the inflationary dynamics may also be controlled by this residue and therefore related to the Fermi-to-Planck mass ratio, up to possible uncertainties associated with the instanton regularization. We present here a unified framework for this hierarchy generation mechanism, showing that the aforementioned residue can be associated with the curvature of the Einstein-frame target manifold in models displaying spontaneous breaking of dilatations. Our findings are illustrated through examples previously considered in the literature.

We present a novel Affleck–Dine scenario for the generation of the observed baryon asymmetry of the Universe based on the non-trivial interplay between quintessential inflationary models containing a kinetic dominated post-inflationary era and a non-minimally coupled U(1) field with a weakly broken B−L symmetry. The non-minimal coupling to gravity renders heavy the Affleck–Dine field during inflation and avoids the generation of isocurvature fluctuations. During the subsequent kinetic era the Ricci scalar changes sign and the effective mass term of the Affleck–Dine field becomes tachyonic. This allows the field to dynamically acquire a large expectation value. The symmetry of the Affleck–Dine potential is automatically restored at the onset of radiation domination, when the Ricci scalar approximately equals zero. This inverse phase transition results in the coherent oscillation of the scalar field around the origin of its effective potential. The rotation of the displaced Affleck–Dine field in the complex plane generates a non-zero B−L asymmetry which can be eventually converted into a baryon asymmetry via the usual transfer mechanisms.

We consider a minimally-coupled inflationary theory with a general scalar potential V(f(φ))=V(ξ∑k=1nλkφk) containing a stationary point of maximal order m. We show that asymptotically flat potentials can be associated to stationary points of infinite order and discuss the relation of our approach to the theory of α-attractors.

We study the geometrical properties of scale-invariant two-field models of inflation. In particular, we show that when the field-derivative space in the Einstein frame is maximally symmetric during inflation, the inflationary predictions can be universal and independent of the details of the theory.