Infrared Cutoff in the Primordial Power Spectrum from Loop Quantum Cosmology: Statistical Comparison with Planck 2018 Low-l TT Data

We present a statistical analysis of a primordial power spectrum modified by an infrared cutoff motivated by Loop Quantum Cosmology (LQC). In LQC, the quantum bounce at Planck density naturally suppresses primordial fluctuations on the largest scales. We fit this model to the Planck 2018 low-l TT Commander bandpowers (l = 2-30) using CAMB v1.5.3. The best-fit cutoff scale is kcut = 4.77e-4 Mpc^-1. The LQC cutoff model yields chi2_red = 0.66 versus 0.96 for LCDM, with delta_chi2 = 9.19, delta_AIC = 7.19, and p-value = 0.0024, representing strong statistical preference. The improvement is localized at l <= 5, consistent with the CMB quadrupole deficit. All data are from the Planck Legacy Archive (IRSA) and all code is publicly available at https://github.com/francecosam-wq/LQC-IR-cutoff  