Títulol: Observational imprints of primordial gravitational waves on the CMB temperature anisotropies and (B-mode) polarization

Lugar: Seminario del DAA. Edificio Investigación Jeronimo Muñoz, planta cuarta, en Burjassot.

Día: Lunes 3 de marzo de 2025. Hora: 12:00.

Resumen:

Observational imprints of inflationary field(s) on the Cosmic Microwave Background (CMB) play a fundamental role to understand the first stages of the early universe, quite before the time of decoupling and after the Planck epoch. In this talk, we first focus on temperature angular correlations, considering both scalar and tensor modes yielding primary anisotropies (at large angular scale, i.e., small $\ell$). Then, we address the B-mode polarization induced by tensor modes (due to primordial gravitational waves) on the CMB with potentially remarkable observational consequences on the BB power spectrum to be obtained from high-precision measurements by forthcoming satellite missions like LiteBIRD.

From the theoretical side, a doublet of infrared cutoffs $k_{min}^{even/odd}$ is introduced to both the scalar and tensor angular power spectra, by invoking an extra Kaluza-Klein spatial dimension compactifying at the GUT era, whose inverse radius provides the cutoff energy scale. Furthermore, the topology associated with (Dirichlet and von-Neumann) boundary conditions on the compactified extra dimension yields “naturally” the required doublet structure with the ratio $k_{min}^{even}/k_{min}^odd} = 2$, favored by fits to observational data on temperature correlations already measured by COBE, WMAP and Planck satellite missions.

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M.A. Sanchis-Lozano and V. Sanz, Phys.Rev. D 109 (2024) 6, 063529

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