Browsing by Author "Muhammad Ehsan Khalid,"

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    Cosmological Bouncing Solutions With Different
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2019) Muhammad Ehsan Khalid,; FA17-RMT-020; Dr. Muhammad Zubair,; LHR TP 5653
    Cosmological bouncing scenarios provide an alternative to the standard Big Bang paradigm by replacing the initial singularity with a finite minimum scale factor, followed by a transition from contraction to expansion. In this work, we investigate a class of bouncing solutions arising from different theoretical frameworks, including modified gravity theories, scalar field dynamics, and quantum cosmological effects. By analyzing the behavior of the Hubble parameter and the evolution of the scale factor, we identify the necessary conditions for a successful, non-singular bounce. Particular attention is given to the role of energy conditions, stability criteria, and the avoidance of ghost and gradient instabilities. We compare the physical viability of various models and discuss their implications for early-universe evolution, structure formation, and observational signatures in the cosmic microwave background. Our results demonstrate that a wide range of theoretical approaches can consistently produce stable and realistic bouncing cosmologies, offering promising alternatives to inflationary scenarios.