What are operators?

Some articles on operators, operator:

Radio Amateur Civil Emergency Service - Participation
... To prevent abuse of station licenses by officials who were not licensed amateur radio operators, limitations on the duration of non-emergency operation and ... would now use licensed amateur radio operators as control operators ... In daily practice, most amateur radio operators enrolled with their local government for possible operations under the RACES rules are also members of the Amateur Radio Emergency Service ...
Interaction Picture
... two pictures either the state vector or the operators carry time dependence, in the interaction picture both carry part of the time dependence of observables ... Equations that include operators acting at different times, which hold in the interaction picture, don't necessarily hold in the Schrödinger or the Heisenberg picture ... time-dependent unitary transformations relate operators in one picture to the analogous operators in the others ...
Operator Product Expansion
... In quantum field theory, the operator product expansion (OPE) is a Laurent series expansion of two operators ... quantum field theory one is interested in the result of physical observables represented by operators ... observations at two points and, one can time order these operators in increasing time ...
Noncommutative Logic - Noncommutativity in Logic - Pomset Logic
... Retoré in a semantic formalism with two dual sequential operators existing together with the usual tensor product and par operators of linear logic, the first logic proposed to have ...