Quantized detector networks (QDN) deal with observers and their apparatus rather than with systems under observation. QDN can be used to investigate the detailed structure of particle decays and the quantum Zeno effect without assuming temporal continuity or invoking non-Hermitian Hamiltonians or complex energies. The formalism is applied to single channel decays, the ammonium molecule and neutral Kaon and B meson decays.
Quantized detector networks (QDN) deal with observers and their apparatus rather than with systems under observation. QDN can be used to investigate the detailed structure of particle decays and the quantum Zeno effect without assuming temporal continuity or invoking non-Hermitian Hamiltonians or complex energies. The formalism is applied to single channel decays, the ammonium molecule and neutral Kaon and B meson decays.
Introduction In this chapter we discuss experiments where the run architecture is significantly different from that of standard in-out experiments such as particle scattering. We apply the quantized detector network (QDN) formalism to particle decays, the ammonium molecular system, Kaon-type regeneration decay experiments, and quantum Zeno experiments. In all of these experiments, the problem is the modeling of time, which conventionally is taken to be continuous. In QDN, time is treated in terms of stages, which are discrete.We show how the QDN formalism deals with such experiments. In standard quantum mechanics (QM), time is assumed to be continuous. That is a legacy from classical mechanics (CM), which does not concern itself in general with the processes of observation. CMassumes systems under observation (SUOs) “have” physical properties that are independent of how they are observed. In contrast, QM cannot be considered without a discussion of the processes of observation. On close inspection of any process of observation, as it is actually carried out in the laboratory and not how it is modeled theoretically , the continuity of time does not look quite so obvious. The problem is that there are two mutually exclusive views about the nature of observation in physics. These were discussed in detail by Misra and Sudarshan (MS) in an influential paper on the quantum Zeno effect (Misra and Sudarshan, 1977). On the one hand, no known principle forbids the continuity of time, so the axioms of QM are stated implicitly in terms of continuous time. When the Schrödinger equation is postulated to be one of them (Peres, 1995), temporal continuity is assumed explicitly. On the other hand, it is an empirical fact that no experiment can actually monitor any SUO in a truly continuous way. All references to continuous time measurements are invariably based on statistical modeling of complex processes, with the continuity of time having much the same status as that of temperature. Such effective parameters are extremely useful in physics, but their status as model-dependent, emergent attributes of SUOs, and the apparatus used to observe them, should always be kept in mind. The best that could be done toward simulating temporal continuity in physics would be to perform a sequence of experiments with a carefully prescribed decreasing measurement time scale, such as occurs in experiments investigating the phenomenon known as the quantum Zeno effect (Itano et al., 1990).
Particle Decays IntroductionIn this chapter we discuss experiments where the run architecture is significantly different from that of standard in-out experiments such as particle scattering.We apply the quantized detector network (QDN) formalism to particle decays, the ammonium molecular system, Kaon-type regeneration decay experiments, and quantum Zeno experiments.In all of these experiments, the problem is the modeling of time, which conventionally is taken to be continuous.In QDN, time is treated in terms of stages, which are discrete.We show how the QDN formalism deals with such experiments.In standard quantum mechanics (QM), time is assumed to be continuous.That is a legacy from classical mechanics (CM), which does not concern itself in general with the processes of observation.CM assumes systems under observation (SUOs) "have" physical properties that are independent of how they are observed.In contrast, QM cannot be considered without a discussion of the processes of observation.On close inspection of any process of observation, as it is actually carried out in the laboratory and not how it is modeled theoretically, the continuity of time does not look quite so obvious.The problem is that there are two mutually exclusive views about the nature of observation in physics.These were discussed in detail by Misra and Sudarshan (MS) in an influential paper on the quantum Zeno effect (Misra and Sudarshan, 1977).On the one hand, no known principle forbids the continuity of time, so the axioms of QM are stated implicitly in terms of continuous time.When the Schrödinger equation is postulated to be one of them (Peres, 1995), temporal continuity is assumed explicitly.On the other hand, it is an empirical fact that no experiment can actually monitor any SUO in a truly continuous way.All references to continuous time measurements are invariably based on statistical modeling of complex processes, with the continuity of time having much the same status as that of temperature.Such effective parameters are extremely useful in
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 also discussed.
Motivation The aim of this book is to introduce, develop, and apply quantized detector networks (QDN), an information-based, observer-centric approach to quantum mechanics (QM). Six reasons motivating our development of QDN are the following. Avoidance of Metaphysical Speculation There is such a variety of unproven (and unprovable) speculation concerning the interpretation of QM that the subject of this book, QDN, may appear at first sight to be yet another in this growing branch of metaphysics. In fact, our motivation is precisely the opposite. QDN was intended from the outset to reduce the level of metaphysics in the application of QM. To achieve this, our strategy is to move the traditional focus of attention away from systems under observation (SUOs) and toward the observers of those SUOs. In QDN, wave functions represent not states of SUOs but states of apparatus. We shall call such states labstates , to distinguish them from states of SUOs (which do have a place in QDN). It is only labstates that observers can ever deal with directly. In this respect, QDN is an attempt at a more laboratory-based description of quantum physics than standard QM, focusing as much on how an experiment is done as on the results of that experiment. For example, instead of talking about the wave function of an electron, QDN talks about the labstate of the signal detectors that allow us to say anything about that electron in the first place. That is all, there is nothing deeper. Whether or not electrons actually “exist” is thereby relegated to an inessential metaphysical issue that we can choose to ignore. It is important to understand what QDN does not say as much as what it does say. QDN does not say that electrons do not “exist”. QDN merely asks for an empirical definition of “existence”. QM Is Much More Than a Calculational Device Many physicists hold the utilitarian view that the success of quantum theory in predicting experimental data is sufficient for their purposes, and that further inquiry is really the business of metaphysics and therefore outside the scope of science proper. We cannot say that this is entirely unreasonable. However, we take the view that QM represents such a radical departure from the principles of classical mechanics (CM) that this pragmatical view cannot be all there is to the subject.