Heyl, Jeremy S.Loeb, Abraham2019-09-272002Heyl, Jeremy S., and Abraham Loeb. 2002. “Vacuum Decay Constraints on a Cosmological Scalar Field.” Physical Review Letters 88 (12). https://doi.org/10.1103/physrevlett.88.121302.0031-90071079-71141092-0145http://nrs.harvard.edu/urn-3:HUL.InstRepos:41417284If the potential of a scalar filed phi which currently provides the dark energy of the Universe has a minimum at phi = -M-0(4) < 0, then quantum-mechanical fluctuations could nucleate a bubble of φ at a negative value of the potential. This bubble would then expand at the speed of light. Given that no such bubble enveloped us in the past, we find that any minimum in V(φ) must be separated from the current φ value by more than min{1.5M(⊙), 0.21M(P1)} where M-P1 is the Planck mass. We also show that vacuum decay renders a cyclic or ekpyrotic universe with M-0(4) greater than or similar to 10(-10) M-P1(4) untenable.en-USJournal Article2019-09-2710.1103/PhysRevLett.88.121302