Mass hierarchies and nondecoupling in multi-scalar-field dynamics
Abstract
In this work, we study the effects of field space curvature on scalar field perturbations around an arbitrary background field trajectory evolving in time. Nontrivial imprints of the “heavy” directions on the low-energy dynamics arise when the vacuum manifold of the potential does not coincide with the span of geodesics defined by the sigma model metric of the full theory. When the kinetic energy is small compared to the potential energy, the field traverses a curve close to the vacuum manifold of the potential. The curvature of the path followed by the fields can still have a profound influence on the perturbations, as modes parallel to the trajectory mix with those normal to it if the trajectory turns sharply enough. We analyze the dynamical mixing between these nondecoupled degrees of freedom and deduce its nontrivial contribution to the low-energy effective theory for the light modes. We also discuss the consequences of this mixing for various scenarios where multiple scalar fields play a vital role, such as inflation and low-energy compactifications of string theory.
- Publication:
-
Physical Review D
- Pub Date:
- August 2011
- DOI:
- 10.1103/PhysRevD.84.043502
- arXiv:
- arXiv:1005.3848
- Bibcode:
- 2011PhRvD..84d3502A
- Keywords:
-
- 98.80.Cq;
- 04.62.+v;
- 04.65.+e;
- Particle-theory and field-theory models of the early Universe;
- Quantum field theory in curved spacetime;
- Supergravity;
- High Energy Physics - Theory;
- Astrophysics - Cosmology and Extragalactic Astrophysics;
- General Relativity and Quantum Cosmology;
- High Energy Physics - Phenomenology
- E-Print:
- 16 pages, 2 figures, typeset in PRD style. v2: Minor changes throughout to emphasize that the analysis also applies to sharp and/or prolonged turns. References added