Evolving Dark Energy DESIderata (CANCELLED)

by Prof. George Efstathiou (University of Cambridge)

Wednesday 9 Sept 2026, 14:00 → 16:00 Europe/Zurich

503/1-001 - Council Chamber (CERN)

This talk is part of the TH institute : UNDARK 2026: Illuminating Cosmic Discord

The Lambda Cold Dark Matter model has emerged as the standard model of Cosmology. It provides an extremely accurate description of the temperature, polarization and lensing fluctuations in the cosmic microwave background radiation and also of  a wide range of early and late time obervables. In this model, dark energy is described by a cosmological constant. However, recent observation with the Dark Energy Spectrosopic Instrument (DESI) have been interpreted as evidence for evolving dark energy. As a result  hundreds of papers have been written  exploring extensions to the Lambda CDM cosmology. I will deconstruct the arguments of the DESI collaboration and show that the evidence for evolving dark energy is extraordinarily weak. Dark energy desiderata do not yet break the Lambda CDM model.