Asymptotically safe cosmology with non-canonical scalar field

Rituparna Mandal; Soma Sanyal

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arXiv · 2403.02852

Asymptotically safe cosmology with non-canonical scalar field

Rituparna Mandal·Soma Sanyal

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Abstract

We investigate the quantum modified cosmological dynamical equations in a Friedmann-Robertson-Walker universe filled with a barotropic fluid and a general non-canonical scalar field characterized by a Lagrangian similar to k-essence model but with a potential term. Quantum corrections are incorporated by considering the running of gravitational and potential couplings, employing the functional renormalization group approach. Covariant conservation of the non-canonical scalar field and the background barotropic fluid is considered separately, imposing a constraint resulting from the Bianchi identity. This constraint determines the evolution of the cut-off scale with the scale factor and also reveals cosmic fixed points, depending on whether the flow ceases or continues to evolve. We explore how the general non-canonical scalar field parameter affects the different types of cosmic fixed points and how it differs from the canonical case. Furthermore, we establish a bound on the ratio of the RG parameters involving the non-canonical parameter for which the universe may exhibit accelerated expansion for mixed fixed points. This bound indicates the non-canonical scalar field includes larger sets of RG fixed point which may give rise to an accelerated universe.

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Rituparna Mandal, Soma Sanyal. 2024-03-05. Asymptotically safe cosmology with non-canonical scalar field. https://arxiv.org/abs/2403.02852

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