On backreaction effects in geometrical destabilisation of inflation

Abstract

We study the geometrical instability arising in multi-field models of inflation with negatively-curved field space. We analyse how the homogeneous background evolves in presence of geometrical destabilisation, and show that, in simple models, a kinematical backreaction effect takes place that shuts off the instability. We also follow the evolution of the unstable scalar fluctuations. We show that they assist the kinematical backreaction while remaining in the perturbative regime. We conclude that, in the simplest models of geometrical destabilisation, inflation does not end prematurely, but rather proceeds along a modified, sidetracked, field-space trajectory.

25 pages, 4 figures, matches the published version

References in corpus (3)

• Curvature and isocurvature perturbations in two-field inflation
• On reaching the adiabatic limit in multi-field inflation
• Geometrical destabilization, premature end of inflation and Bayesian model selection

Cited by in corpus (11)

• Revisiting small-scale fluctuations in $\alpha$-attractor models of inflation
• The rapid-turn inflationary attractor
• A manifestly covariant theory of multifield stochastic inflation in phase space: solving the discretisation ambiguity in stochastic inflation
• On the inflationary massive field with a curved field manifold
• Mild Non-Gaussianities under Perturbative Control from Rapid-Turn Inflation Models
• Higgs vacuum (in)stability during inflation: the dangerous relevance of de Sitter departure and Planck-suppressed operators
• Geometrical Destabilisation of Ultra-Light Axions in String Inflation
• Large and small field inflation from hyperbolic sigma models
• Non-Gaussianity in rapid-turn multi-field inflation
• Anatomy of geometrical destabilization of inflation
• On the F-term problem and quintessence supersymmetry breaking