Quantum decoherence of primordial perturbations through nonlinear
  scaler-tensor interaction
  Scaler and tensor perturbations couple nonlinearly with each other in the
Einstein-Hilbert action. We show that such interaction naturally leads to the
quantum decoherence of the primordial perturbations during inflation at horizon
crossing. The dominant interaction Hamiltonian contributing to decoherence is
identified and the master equation responsible for the decohering process is
derived.
