On de Sitter space, there exists a special value for the mass of a graviton for which the linear theory propagates 4 rather than 5 degrees of freedom, known as a partially massless graviton. If a satisfactory non-linear version of the theory can be found and coupled to known matter, it would have interesting properties and could solve the cosmological constant problem. I will review attempts at constructing such a theory and some no-go’s, and will describe a Vasiliev-like theory containing a tower of partially massless higher spins.

Page last modified: May 12, 2016