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arXiv · 2102.04744

Cosmological dynamics and bifurcation analysis of the general non-minimally coupled scalar field models

Wompherdeiki Khyllep·Jibitesh Dutta
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Abstract

Non-minimally coupled scalar field models are well-known for providing interesting cosmological features. These include a late time dark energy behavior, a phantom dark energy evolution without singularity, an early time inflationary universe, scaling solutions, convergence to the standard $\Lambda$CDM, etc. While the usual stability analysis helps us determine the evolution of a model geometrically, bifurcation theory allows us to precisely locate the parameters' values describing the global dynamics without a fine-tuning of initial conditions. Using the center manifold theory and bifurcation analysis, we show that the general model undergoes a transcritical bifurcation, which predicts us to tune our models to have certain desired dynamics. We obtained a class of models and a range of parameters capable of describing a cosmic evolution from an early radiation era towards a late time dark energy era over a wide range of initial conditions. There is also a possible scenario of crossing the phantom divide line. We also find a class of models where the late time attractor mechanism is indistinguishable from that of a structurally stable general relativity based model; thus, we can elude the big rip singularity generically. Therefore, bifurcation theory allows us to select models that are viable with cosmological observations.

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Wompherdeiki Khyllep, Jibitesh Dutta. 2021-02-09. Cosmological dynamics and bifurcation analysis of the general non-minimally coupled scalar field models. https://doi.org/10.1140/epjc%2Fs10052-021-09559-x

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