Browsing by Author "Gupt, B."

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    Alleviating the Tension in the Cosmic Microwave Background Using Planck-Scale Physics
    (American Physical Society subs@aip.org;revtex@aps.org;prx@aps.org;prxtex@aps.org;help@aps.org;prb@aps.org, 2020) Ashtekar, A.; Gupt, B.; Jeong, D.; Sreenath, V.
    Certain anomalies in the CMB bring out a tension between the six-parameter flat ?CDM model and the CMB data. We revisit the PLANCK analysis with loop quantum cosmology (LQC) predictions and show that LQC alleviates both the large-scale power anomaly and the tension in the lensing amplitude. These differences arise because, in LQC, the primordial power spectrum is scale dependent for small k, with a specific power suppression. We conclude with a prediction of larger optical depth and power suppression in the B-mode polarization power spectrum on large scales. © 2020 American Physical Society.
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    Cosmic Tango Between the Very Small and the Very Large: Addressing CMB Anomalies Through Loop Quantum Cosmology
    (Frontiers Media S.A., 2021) Ashtekar, A.; Gupt, B.; Sreenath, V.
    While the standard, six-parameter, spatially flat (Formula presented.) model has been highly successful, certain anomalies in the cosmic microwave background bring out a tension between this model and observations. The statistical significance of any one anomaly is small. However, taken together, the presence of two or more of them imply that according to standard inflationary theories we live in quite an exceptional Universe. We revisit the analysis of the PLANCK collaboration using loop quantum cosmology, where an unforeseen interplay between the ultraviolet and the infrared makes the primordial power spectrum scale dependent at very small k. Consequently, we are led to a somewhat different (Formula presented.) Universe in which anomalies associated with large scale power suppression and the lensing amplitude are both alleviated. The analysis also leads to new predictions for future observations. This article is addressed both to cosmology and loop quantum gravity communities, and we have attempted to make it self-contained. © Copyright © 2021 Ashtekar, Gupt and Sreenath.