Using the formalism of Boucher we derive the conditions under which gravity can stabilize otherwise metastable or unstable scalar field configurations. For the case of a double-welled potential we rederive the stability criteria first obtained by Coleman and DeLuccia. Our derivation does not require the assumption of 0(4) symmetry or the thin-walled approximation used in their work. We also giv...

We show that in a two-dimensional model of quantum gravity the summation over all possible wormhole configurations leads to kind Coleman mechanism where cosmological constant plays no role for large universes. Observers who are unable observe change topology will naturally interpret measurements size universe as being caused by fluctuating constant, rather than spacetime.

We study properties of Abrikosov-Nielsen-Olesen (ANO) strings with the Coleman-Weinberg (CW) potential, which we call CW-ANO strings. While scale-invariant scalar potential has a topologically trivial vacuum admitting no at classical level, quantum correction allows nontrivial vacua and stable string solutions. find that system CW exhibits significant difference from conventional Abelian-Higgs ...