$R^2$ Gravity Effects on the Kinetic Axion Phase Space

Abstract

In this work we consider the effect of an $R^2$ term on the kinetic misalignment axion theory. By using the slow-roll assumptions during inflation and the field equations, we construct an autonomous dynamical system for the kinetic axion, including the effects of the $R^2$ term and we solve numerically the dynamical system. As we demonstrate, the pure kinetic axion attractor is transposed to the right in the field phase space, and it is no longer $(\varphi ,\dot{\varphi })=(⟨\varphi ⟩,0)$, but it is $(\varphi ,\dot{\varphi })=(⟨{\varphi }^{\prime }⟩,0)$, with $⟨{\varphi }^{\prime }⟩\ne 0$ some non-zero value of the scalar field with $⟨{\varphi }^{\prime }⟩>⟨\varphi ⟩$. This feature indicates that the kinetic axion mechanism is enhanced, and the axion oscillations are further delayed, compared with the pure kinetic axion case. The phenomenological implications on the duration of the inflationary era, on the commencing of the reheating era and the reheating temperature, are also discussed.

EPL in press

References in corpus (10)

• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• Class of viable modified $f(R)$ gravities describing inflation and the onset of accelerated expansion
• Palatini Approach to Modified Gravity: f(R) Theories and Beyond
• Bose-Einstein Condensation of Dark Matter Axions
• Modified f(R) gravity unifying R^m inflation with \LambdaCDM epoch
• Dark Matter and Collider Phenomenology of Universal Extra Dimensions
• Resonant detection of axion mediated forces with Nuclear Magnetic Resonance
• Direct Detection of Dark Matter Rates for Various Wimps
• Oscillating Chiral Tensor Spectrum from Axionic Inflation
• Kinetic Axion $F(R)$ Gravity Inflation

Cited by in corpus (3)

• Effects of the Axion Through the Higgs Portal on Primordial Gravitational Waves During the Electroweak Breaking
• Kinetic Axion Dark Matter in String Corrected $f(R)$ Gravity
• The interaction of extended Bose-Einstein condensate dark matter with viscous $f(T,B)$ gravity