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The Cosmological Constant $Lambda$, in different incarnations, has been with us for 100 years. Many surveys of dark energy are underway, indicating so far that the data are consistent with a dark energy equation of state of $w=-1$, i.e. a $Lambda$ term in Einsteins equation, although time variation of $w$ is not yet ruled out. The ball is now back in the theoreticians court, to explain the physical meaning of $Lambda$. We discuss sociological aspects of this field, in particular to what extent the agreement on the cold dark matter + $Lambda$ concordance model is a result of the globalization of research and over-communication.
Euclid is the next ESA mission devoted to cosmology. It aims at observing most of the extragalactic sky, studying both gravitational lensing and clustering over $sim$15,000 square degrees. The mission is expected to be launched in year 2020 and to la
We study the matter density fluctuations in the running cosmological constant (RCC) model using linear perturbations in the longitudinal gauge. Using this observable we calculate the growth rate of structures and the matter power spectrum, and compar
The standard concordance model of the Universe is based on the cosmological constant as the driver of accelerating expansion. This concordance model is being subjected to a growing range of inter-locking observations. In addition to using generic obs
Cosmological observations offer unique and robust avenues for probing the fundamental nature of dark matter particles-they broadly test a range of compelling theoretical scenarios, often surpassing or complementing the reach of terrestrial and other
It is well known that string theories naturally compactify on anti-de Sitter spaces, and yet cosmological observations show no evidence of a negative cosmological constant in the early Universes evolution. In this letter we present two simple nonloca