Showing papers by "Matt Visser published in 1991"
TL;DR: In this paper, the authors obtained explicit closed-form expressions for the one-loop effective action in a constant electromagnetic field and discussed both massive and massless charged scalars and spinors in two, three and four dimensions.
Abstract: Motivated by the seminal work of Schwinger, we obtain explicit closed-form expressions for the one-loop effective action in a constant electromagnetic field. We discuss both massive and massless charged scalars and spinors in two, three and four dimensions. Both strong-field and weak-field limits are calculable. The latter limit results in an asymptotic expansion whose first term reproduces the Euler-Heinsenberg effective Lagrangian. We use the prescription of zeta-function renormalization, and indicate its relationship to Schwinger’s renormalized effective action.
61 citations
TL;DR: In this paper, it was shown that the throat of a minisuperspace Wheeler wormhole is stabilized against collapse by quantum mechanical effects: the radius of the throat has an expectation value of order the Planck length.
Abstract: Wheeler's wormholes are analyzed within the context of a particular minisuperspace approximation. In this approximation the Wheeler-DeWitt equation describing a wormhole is exactly solvable and the quantum mechanical wavefunction of a wormhole can be explicitly exhibited. Calculation shows that the throat of a minisuperspace Wheeler wormhole is stabilized against collapse by quantum mechanical effects: The radius of the throat has an expectation value of order the Planck length. Implications of this result with respect to the process of quantum gravitational topology change are discussed. In particular it is argued that the putative stability of minisuperspace Wheeler wormholes—if it persists beyond the minisuperspace approximation—might serve to suppress fluctuations in topology.
8 citations