Stabilizing the gravitational action and Coleman's solution to the cosmological constant problem

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We use the 5-th time action formalism introduced by Halpern and Greensite to stabilize the unbounded Euclidean 4-D gravity in two simple minisuperspace models. In particular, we show that, at the semiclassical level (ℏ → 0), we still have as a leading saddle point the S⁴ solution and the Coleman peak at zero cosmological constant, for a fixed De Witt supermetric. At the quantum (one-loop) level the scalar gravitational modes give a positive semi-definite Hessian contribution to the 5-D partition function, thus removing the Polchinski phase ambiguity.