The Swampland: Consistency constraints on effective theories from quantum gravity


  Eran Palti  
Ben-Gurion University of the Negev

Theories of physics are typically only valid up to a certain energy scale, their cutoff. The modern Wilsonian implementation of such a cutoff is through the construction of effective theories following certain rules. I will review a recent program of research in theoretical physics, the Swampland program, which suggests that these long-standing rules must be extended and supplement by additional constraints coming from consistency with gravity and quantum mechanics simultaneously. These new constraints range in their nature, the strength of the evidence for them, and in their implications: from requiring that gravity must always be the weakest force in any effective theory of physics, to requiring that a cosmological constant cannot be positive.