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arXiv · 2503.03076

Non-Affine Extensions of the Raychaudhuri Equation in the K-essence Framework

Samit Ganguly·Goutam Manna·Debashis Gangopadhyay·Eduardo Guendelman·Abhijit Bhattacharyya
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Abstract

We present a new avenue of the Raychaudhuri Equation (RE) by introducing a non-affine parametrization within the k-essence framework. This modification accounts for non-geodesic flow curves, leading to emergent repulsive effects in cosmic evolution. Using a DBI-type k-essence Lagrangian, we derive a modified RE and demonstrate its ability to address the Hubble tension while predicting a natural emergence of a dynamical dark energy equation of state. Our Bayesian analysis, constrained by cosmological data, supports the theoretical scaling relation of the k-essence field ($\dot{\phi}$) and the cosmic scale factor ($a$). Furthermore, we reinterpret the modified RE as an anti-damped harmonic oscillator, we found a caustic avoidance signature, it may reveal classical or quantum-like effects in cosmic expansion. These results suggest a deep connection between scalar field dynamics and modified gravity, offering new perspectives on the nature of the expansion history of the universe.

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Samit Ganguly, Goutam Manna, Debashis Gangopadhyay, Eduardo Guendelman, Abhijit Bhattacharyya. 2025-03-05. Non-Affine Extensions of the Raychaudhuri Equation in the K-essence Framework. https://doi.org/10.1016/j.physletb.2025.139622

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