Abstract

Almost a century ago Einstein’s seminal paper -Cosmological Considerations in the General Theory of Relativity- (2 August 1917) proposed a game changing addition to his theory of general relativity: Lambda, the cosmological constant. Since then, and in particular from the remarkable experimental data gathered during the last two decades, the cosmological constant has gone from a theoretical sideline to a central feature of research in cosmology and quantum gravity, including the effective Λ of inflation, the observed Λ of the late time acceleration of our universe, and the negative Λ of the gauge/gravity correspondence in string theory. Theoreticians and philosophers have been fascinated and aggravated by -the Lambda Problem- for a century. The advent of precision cosmology has made this an issue of practical relevance, and this workshop will be productive through critiquing and advancing theoretical approaches within the constraints of observations.