  Full formal descriptions of algorithms making use of quantum principles must
take into account both quantum and classical computing components and assemble
them so that they communicate and cooperate.Moreover, to model concurrent and
distributed quantum computations, as well as quantum communication protocols,
quantum to quantum communications which move qubits physically from one place
to another must also be taken into account.
  Inspired by classical process algebras, which provide a framework for
modeling cooperating computations, a process algebraic notation is defined,
which provides a homogeneous style to formal descriptions of concurrent and
distributed computations comprising both quantum and classical parts.Based upon
an operational semantics which makes sure that quantum objects, operations and
communications operate according to the postulates of quantum mechanics, a
probabilistic branching bisimulation is defined among processes considered as
having the same behavior.
