Constraint on the Squeeze Parameter of Inflaton from Cosmological   Constant
  The inflaton is highly likely to settle in a squeezed vacuum state after inflation. The relic inflaton after inflation and reheating undergoes a damped oscillatory motion and contributes to the effective cosmological constant. We interpret the renormalized energy density from the squeezed vacuum state as an effective cosmological constant. Using the recent observational data on the cosmological constant, we find the constraint on the squeeze parameter of the inflaton in the early universe. 
Sang Pyo Kim and Seoktae Koh (Kunsan Nat'l Univ)