| Name: Debarshi Mukherjee |
| Affiliation: Indian Institute of Science Education and Research Berhampur |
| Conference ID: ASI2026_322 |
| Title: Model Independent Primordial Power Spectrum Reconstruction from CMB Temperature Spectrum |
| Abstract Type: Poster |
| Abstract Category: Galaxies and Cosmology |
| Author(s) and Co-Author(s) with Affiliation: Debarshi Mukherjee(Indian Institute of Science Education and Research Berhampur, Berhampur - 760003, India), Rajorshi Sushovan Chandra(Raman Research Institute, Bengaluru - 560080, India), Tarun Souradeep(Raman Research Institute, Bengaluru - 560080, India) |
| Abstract: The primordial power spectrum (PPS) sourced from cosmological inflation provides a direct probe of the physical processes operating in the early universe. Recovering this information from the cosmic microwave background (CMB) observations is an intrinsically ill-posed inverse problem in the context of a non-parametric reconstruction, further limited by cosmic variance, instrumental noise, and the smoothing effects of radiative transfer. In this work, we present a non-parametric reconstruction of the PPS using the Non-linear Iterative Richardson-Lucy (NIRL) method. Unlike conventional iterative deconvolution techniques, NIRL recasts the Richardson–Lucy estimator into a single-step formulation to handle nonlinear biases as well as optimize the uniqueness of the solution. The method constructs the PPS directly from the CMB temperature angular power spectrum without assuming any inflationary model, lensing template, or predefined functional form. Tests on simulated CMB spectra with Planck-like noise show that NIRL reliably recovers both smooth trends and localized features while remaining stable under realistic uncertainties. Our work demonstrates that NIRL offers a simple, robust, and physically transparent route for model-independent studies of primordial perturbations and their cosmological implications. |
