QDN (quantized detector networks) is a description of quantum processes in
which the principal focus is on observers and their apparatus, rather than on
states of SUOs (systems under observation). It is a realization of Heisenberg's
original instrumentalist approach to quantum physics and can deal with time
dependent apparatus, multiple observers and inter-frame physics. QDN is most
naturally expressed in the mathematical language of quantum computation, a
language ideally suited to describe quantum experiments as processes of
information exchange between observers and their apparatus. Examples in quantum
optics are given, showing how the formalism deals with quantum interference,
non-locality and entanglement. Particle decays, relativity and non-linearity in
quantum mechanics are discussed.Comment: 59 pages, 14 figures, to be published in Int. J. Mod. Phys.