Elitzur-Vaidman bomb tester
= Elitzur-Vaidman bomb tester
{c}
{wiki=Elitzur–Vaidman_bomb_tester}
A <photon> in a <quantum superposition> of a safe path and an absorbing path can sometimes certify a live absorber without being absorbed. Recombination is chosen so that one output is impossible if the absorber is absent. A detection at that output is then an unambiguous successful test. The measurement back-action of a surviving live-absorber trial changes the interference pattern.