Thursday, November 28, 2024, 16:00
online
George Efstathiou, Cambridge University
Abstract:
Observations of the cosmic microwave background (CMB) anisotropies
provide strong evidence in support of the ΛCDM cosmology. Nevertheless,
a number of 'tensions' have emerged. I will review: (a) recent results
from the CMB that have strengthened the evidence in favour of ΛCDM; (b)
why it is difficult to explain the discrepancy between the ΛCDM value of
the Hubble constant, H0, and the value derived from the Cepheid
distance scale; (c) why cosmic shear surveys may indicate a
small-scale/large-scale mismatch rather than an inconsistency between
early and late time physics; (d) why the recent DESI results suggesting
evolving dark energy may be driven by systematic errors; (e) why
inflation, a cornerstone of the ΛCDM model, has introduced a new
hierarchy problem in cosmology.