A nongravitational wormhole

Using the effective metric formalism for photons in a nonlinear electromagnetic theory, we show that a certain field configuration in Born-Infeld electromagnetism in flat spacetime can be interpreted as an ultrastatic spherically symmetric wormhole. We also discuss some properties of the effective metric that are valid for any field configuration.Comment: LaTex, 9 pages with 5 figures, minor changes, accepted for publication in Class. Quantum Gra