Dynamical attractors in contracting spacetimes dominated by kinetically coupled scalar fields. Issue 12 (13th December 2021)

• Record Type: Journal Article
• Authors: Ijjas, Anna; Pretorius, Frans; Steinhardt, Paul J.; Garfinkle, David
• Is Part Of: Journal of cosmology and astroparticle physics. Volume 2021:Issue 12(2021)
• Publication Date: 2021-12-13
• Subjects: alternatives to inflation -- cosmological simulations -- gravity -- physics of the early universe; Cosmology -- Periodicals; Astrophysics -- Periodicals; 523.0105
• DOI: 10.1088/1475-7516/2021/12/030
• Languages: English
• ISSNs: 1475-7516

Abstract

Abstract: We present non-perturbative numerical relativity simulations of slowly contracting spacetimes in which the scalar field driving slow contraction is coupled to a second scalar field through an exponential non-linear σ model-type kinetic interaction. These models are important because they can generate a nearly scale-invariant spectrum of super-Hubble density fluctuations fully consistent with cosmic microwave background observations. We show that the non-linear evolution rapidly approaches a homogeneous, isotropic and flat Friedmann-Robertson-Walker (FRW) geometry for a wide range of inhomogeneous and anisotropic initial conditions. Ultimately, we find, the kinetic coupling causes the evolution to deflect away from flat FRW and towards a novel Kasner-like stationary point, but in general this occurs on time scales that are too long to be observationally relevant.