Watch out!

I'm not sure what to make of this, but fortunately I deal with teeny weeny pieces of superconductor. Some of my friends like playing with Uranium though.

Pair production in superconductors
Authors: J. E. Hirsch
Comments: better safe than sorry - experimentalists please take note
Subj-class: Superconductivity; Strongly Correlated Electrons

We show that an alternative theory of superconductivity recently proposed (theory of hole superconductivity) leads to the surprising consequence that real electron-positron pair production will occur for superconductors larger than a critical size. We discuss the expected magnitude of the effect and suggest experimental ways to verify it. Urgent attention to the possibility of harmful gamma-radiation being emitted from superconductors out of equilibrium is called for.

cond-mat/0508529