TY - JOUR
T1 - Entropy production in affine inflation
AU - Azri, Hemza
AU - Nasri, Salah
N1 - Publisher Copyright:
© 2020 American Physical Society.
PY - 2020/3/15
Y1 - 2020/3/15
N2 - Multiple scalar fields nonminimally interacting through pure affine gravity are considered to generate primordial perturbations during an inflationary phase. The couplings considered give rise to two distinct sources of entropy perturbations that may not be suppressed in the long wavelength limit. The first is merely induced by the presence of more than one scalar and arises even in the minimal coupling limit. The second source, however, is restricted to nonminimal interaction. Unlike the case of metric gravity, and due to the absence of anisotropic stresses, the second source disappears for a single scalar, showing that nonminimal couplings become relevant to nonadiabatic perturbations only when more than one scalar field are considered. Hence the notion of adiabaticity is not affected by the transition to minimal coupling contrary to the metric gravity case where it is confused by changing the frames. Precise data that might be able to neatly track different sources of isocurvature modes, if any, must not only distinguish between different models of inflation but also determine the most viable approach to gravity that underlies the inflationary dynamics itself.
AB - Multiple scalar fields nonminimally interacting through pure affine gravity are considered to generate primordial perturbations during an inflationary phase. The couplings considered give rise to two distinct sources of entropy perturbations that may not be suppressed in the long wavelength limit. The first is merely induced by the presence of more than one scalar and arises even in the minimal coupling limit. The second source, however, is restricted to nonminimal interaction. Unlike the case of metric gravity, and due to the absence of anisotropic stresses, the second source disappears for a single scalar, showing that nonminimal couplings become relevant to nonadiabatic perturbations only when more than one scalar field are considered. Hence the notion of adiabaticity is not affected by the transition to minimal coupling contrary to the metric gravity case where it is confused by changing the frames. Precise data that might be able to neatly track different sources of isocurvature modes, if any, must not only distinguish between different models of inflation but also determine the most viable approach to gravity that underlies the inflationary dynamics itself.
UR - http://www.scopus.com/inward/record.url?scp=85083801710&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85083801710&partnerID=8YFLogxK
U2 - 10.1103/PhysRevD.101.064073
DO - 10.1103/PhysRevD.101.064073
M3 - Article
AN - SCOPUS:85083801710
SN - 2470-0010
VL - 101
JO - Physical Review D
JF - Physical Review D
IS - 6
M1 - 064073
ER -