The Present Situation in Quantum Theory and its Merging with General Relativity. QM based measurement theory started from the Born rule, then its preliminary formalization was performed by von Neumann and it was based on the projection postulate, finally it was formulated as theory of POVM representable measurements more generally theory of quantum instruments in connection with theory of open quantum systems, see 2. Theory of quantum instruments is mathematically rigorous and clear theory, straightforwardly applicable to the basic quantum experiments. It is important to remark that the only mathematically and conceptually sound QM is nonrelativistic QM. One may disagree and point to relativistic QM. We discuss the problems of quantum theory QT complicating its merging with general relativity GR. QT is treated as a general theory of microphenomenaa bunch. E. C. BRODY the delight of the reader, in spite of his constant return to these familiar ideas, Camus emotions always remain fresh, the. However, the latter suffers of a number of difficult problems, e. By Hegerfeldts theorem Einstein causality implies that there can be no spectral measure solution to the localization problem in relativistic QM. Thus, for a moment, we have the well developed theory of nonrelativistic quantum measurements. Relativistic treatment is presented by QFT based measurement theory, e. Schweber 2. 4, Schwinger 2. My personal opinion confirmed by conversations with a few top experts in quantum measurement theory is that the QFT measurement theory is far from the level of mathematical rigorousness and clearness approached by the QM measurement theory. But this is just the private opinion, cf. I shall present a typical viewpoint representing very general attitude of experimentalists towards quantum measurement theory, a kind of general synthetic statement extracted from conversations during the Vxj series 2. One may say that an experimentalist does not need quantum measurement theory neither in the original von Neumann form Hermitian operators and the projection postulate nor in the modern form POVMs and quantum operations. An experimentalist needs only probabilities for detection of events. Chernyshevsky What Is To Be Done Pdf Reader' title='Chernyshevsky What Is To Be Done Pdf Reader' />These probabilities are provided by QFT. In contrast to QFT, QM is only applicable for the Minkowski gauge. It works only for the flat space. Moreover, the measurement theory in the QFT framework is, in fact, more simple and fundamental than the QM measurement theory von Neumanns theory or modern theory of quantum instruments. Here, in QFT, one can proceed following the ideas of Einstein see, e. Einstein and Infeld 3. Only fields do exist. Any interaction of fields comes with an exchange of their excitations, particles. Any measurement can be treated as the interaction on the observed field with the field of the measurement apparatus may be even including electromagnetic field in experimentalists brain. Any measurement then merely consists of counting the quantum particles arising from the interaction involving the two fields measured input field and measurement apparatus field. QFT express this counting procedure by the measurement and calculation of the current J,  detected by the amount of clicks of the counting device. This measurement of J by counting clicks is exactly what in being measured every day at the LHC machine in Geneva. Do you find in this simple scenario any need for POVM, or entanglements a la Zurek, or quantum instruments a la Davies and Ozawa, or other theoretical nasty procedures It is clear that this viewpoint has some basis behind it. It has to be analyzed in more detail than it is possible in this paper which is not devoted to quantum measurement theory. For me, this position of experimenters is very close to Bohrs position QT is about predictions of outputs of classical measurement devices. The first part of the experimentalists statement about measurement theory would be supported by the majority of experimentalists. The second part related to the field picture of measurement process represents the more specific viewpoint on the quantum measurement theory which is characteristic for some part of the experimental community. From this viewpoint both systems and measurement devices are represented by fields. The above reference to Einstein makes the impression that these fields are treated classically. However, this may be not the case. In general my impression is that often experimentalists treat the operator valued fields of QFT in the same manner as classical fields. We remark that Einstein never accepted the QFT theory, because it shared all the problems of QM, or what he so perceived, most especially its fundamentally nonrealist and acausal, and thus statistical nature. In fact it is not clear to what degree he grasped or, given this character of the theory, even wanted to grasp QFT, or QED. At one point, he developed an interest in Diracs equation, as a spinor equation, and he used it, in his collaborations with W. Mayer, as part of his program for the unified field theory, but, again, conceived as a classical like field theory, modeled on general relativity, and in opposition to quantum mechanics and, by then, quantum field theory. Accordingly, he only considered a classical like spinor form of Diracs equation, thus depriving it of Einstein might have thought freeing it from its quantum features, most fundamentally, discreteness h did not figure in Einsteins form of Diracs equation, and probability. Einstein hoped, but failed to derive discreteness from the underlying field continuity. Einstein was primarily interested in the mathematics of spinors, which he generalized in what he called semi vectors private communication with A. Plotnitsky. One may say that experimentalists still keep to the orthodox Copenhagen interpretation, because they consider the present measurement theory as unsatisfactory. However, I disagree that transition from QM to QFT may simplify measurements picture. Guilherme Souza Nucci Manual Direito Penal Comentado there. I would like to point to the following complication due to the QFT treatment, see also Plotnitsky 1. Chap. 6. Since QM is a nonrelativistic model, the spacetime can be, in principle, excluded from consideration. The ontological interpretation of the wave function psi psi t,x is, although possible, not so much supported by the recent development of quantum foundations. We can by following Schrdinger to interpret a quantum state as an expectations catalog. The Schrdniger dynamics, psi tUt psi 0, need not be coupled to processes in physical spacetime. We remark that von Neumann measurement theory does not describe the process of interaction of a quantum system and a measurement device in physical spacetime. However, by the above argument this is fine in the nonrelativistic QM framework. In QFT, physical spacetime reappeared in whole its power, very similarly to classical field theory. Quantum fields are functions on the spacetime, the only difference from classical field theory is that quantum fields are operator valued. The proper QFT measurement theory has to take the spacetime structure into account and to present the spacetime based picture of interactions of quantum systems fields with measurement devices represented by quantum or even classical fields. To my knowledge, there is no such a theory. It seems that by speaking about simply counting procedures we shadow thremedous difficulties of the theoretical description of these procedures As Pais said years ago 4. Is there a theoretical framework for describing how particles are made and how they vanishThere is quantum field theory. It is a language, a technique, for calculating the probabilities of creation, annihilation, scattering of all sorts of particles photons, electrons, positrons, protons, mesons, others, by methods which to date invariably have the characters of successful approximations. No rigorous expression for the probability of any of the above mentioned processes has ever been obtained. The same is true for the corrections, demanded by quantum field theory, for the positions of energy levels of bound state systems e.