Wochenübersicht für die Woche vom

26 May 2025 bis 01 Jun 2025 (KW 22)

KW19 - KW20 - KW21 - KW22

keine vergangenen Seminare

zukünftige Termine
27 May 2025

Physikalisches Kolloquium

Institut für Physik

16:15 Uhr s.t., HS KPH

Subir Sarkar, University of Oxford
In the ΛCDM cosmological model the Universe is assumed to be isotropic and homogeneous when averaged on large scales. That the Cosmic Microwave Background has a dipole anisotropy is interpreted as due to our peculiar (non-Hubble) motion because of local inhomogeneity. There must then be a corresponding dipole in the sky distribution of sources at high redshift. Using catalogues of radio sources and quasars we find that this expectation is rejected at >5σ, i.e. the distribution of distant matter is not isotropic in the 'CMB frame’. This calls into question the standard practice of boosting to this frame to analyse cosmological data, in particular to infer acceleration of the Hubble expansion rate using Type Ia supernovae, which is then interpreted as due to a Cosmological Constant Λ. We find that the inferred acceleration is anisotropic (in the direction of the CMB hotspot) and likely illusory because of our being embedded in a coherent bulk flow, rather than due to dark energy.

Theorie-Palaver

Institut für Physik

14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor)

Sulagna Bhattacharya, Tata Institute, Mumbai
TBA

28 May 2025

PRISMA+ Colloquium

Institut für Physik

13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7

Prof. Dr. Jacqueline Keintzel, CERN, Geneva, Switzerland
Future colliders: possibilities and challenges