Gravitational open effective field theory of inflation

Abstract: We construct a gravitational open extension of the effective field theory of inflation in the Schwinger-Keldysh framework. While physical symmetries allow many open operators in the Schwinger-Keldysh action, most of them overconstrain the equations of motion, yielding inconsistent dynamics. We identify the minimal open operators compatible with propagating scalar and tensor modes and build the gravitational action, recovering dissipative models of inflation.