Symmetries of Hilbert space effect algebras

Let H be a Hilbert space and E(H) the effect algebra on H, that is, E(H) is the set of all self-adjoint operators A : H → H satisfying 0 ≤ A ≤ I. The effect algebra can be equipped with serveral operations and relations that are important in mathematical foundations of quantum mechanics. Automorphisms with respect to these operations or relations are called symmetries. We present a new method that can be used to describe the general form of such maps. The main idea is to reduce this kind of problems to the study of adjacency preserving maps. The efficiency of this approach is illustrated by reproving some known results as well as by obtaining some new theorems. AMS classification: 47B49, 81P10.