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A symmetry problem in the Copenhagen interpretation

Schmelzer, I.
Tipo: Artigo de Revista Científica
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46.53%
A non-uniqueness result for the canonical structure in quantum theory shows that the classical part of the Copenhagen interpretation contains physically important information not contained in its quantum part. As a consequence, we cannot compute the symmetry group of a quantum theory considering only the quantum part. The unavoidable vagueness of the classical part therefore leads to a similar vagueness in the definition of the symmetry group. This makes it at least problematic, if not impossible, to establish the true symmetry group of a quantum theory in the Copenhagen interpretation. Different from the old measurement problem, the symmetry group is to important physically to be rejected as a metaphysical pseudoproblem.

Copenhagen Interpretation of Quantum Mechanics Is Incorrect

Li, Guang-Liang; Li, Victor O. K.
Tipo: Artigo de Revista Científica
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46.72%
(A point-by-point response to a comment (quant-ph/0509130) on our paper (quant-ph/0509089) is added as Appendix C. We find the comment incorrect.) Einstein's criticism of the Copenhagen interpretation of quantum mechanics is an important part of his legacy. Although most physicists consider Einstein's criticism technically unfounded, we show that the Copenhagen interpretation is actually incorrect, since Born's probability explanation of the wave function is incorrect due to a false assumption on "continuous probabilities" in modern probability theory. "Continuous probability" means a "probability measure" that can take every value in a subinterval of the unit interval (0, 1). We prove that such "continuous probabilities" are invalid. Since Bell's inequality also assumes "continuous probabilities", the result of the experimental test of Bell's inequality is not evidence supporting the Copenhagen interpretation. Although successful applications of quantum mechanics and explanation of quantum phenomena do not necessarily rely on the Copenhagen interpretation, the question asked by Einstein 70 years ago, i.e., whether a complete description of reality exists, still remains open.; Comment: A point-by-point response to a comment (quant-ph/0509130) on our paper (quant-ph/0509089) is added as Appendix C

The Emergent Copenhagen Interpretation of Quantum Mechanics

Hollowood, Timothy J.
Tipo: Artigo de Revista Científica
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46.65%
We introduce a new and conceptually simple interpretation of quantum mechanics based on reduced density matrices of sub-systems from which the standard Copenhagen interpretation emerges as an effective description of macroscopically large systems. Wave function collapse is seen to be a useful but fundamentally unnecessary piece of prudent book keeping which is only valid for macro-systems. The new interpretation lies in a class of modal interpretations in that it applies to quantum systems that interact with a much larger environment. However, we show that it does not suffer from the problems that have plagued similar modal interpretations like macroscopic superpositions and rapid flipping between macroscopically distinct states. We describe how the interpretation fits neatly together with fully quantum formulations of statistical mechanics and that a measurement process can be viewed as a process of ergodicity breaking analogous to a phase transition. The key feature of the new interpretation is that joint probabilities for the ergodic subsets of states of disjoint macro-systems only arise as emergent quantities. Finally we give an account of the EPR-Bohm thought experiment and show that the interpretation implies the violation of the Bell inequality characteristic of quantum mechanics but in a way that is rather novel. The final conclusion is that the Copenhagen interpretation gives a completely satisfactory phenomenology of macro-systems interacting with micro-systems.; Comment: 21 pages

Why QBism is not the Copenhagen interpretation and what John Bell might have thought of it

Mermin, N. David
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.34%
Christopher Fuchs and R\"udiger Schack have developed a way of understanding science, which, among other things, resolves many of the conceptual puzzles of quantum mechanics that have vexed people for the past nine decades. They call it QBism. I speculate on how John Bell might have reacted to QBism, and I explain the many ways in which QBism differs importantly from the orthodox ways of thinking about quantum mechanics associated with the term "Copenhagen interpretation."; Comment: 14 pages. Based on a talk at the conference "Quantum [Un]Speakables II: 50 Years of Bell's Theorem", University of Vienna, June 19, 2014

Decoherence and Copenhagen Interpretation : A Scenario

Fujii, Kazuyuki
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.53%
In this paper we give a reasonable explanation (not proof) to the Copenhagen interpretation of Quantum Mechanics from the view point of decoherence theory. Mathematical physicists with strong mission must prove {\bf the Copenhagen interpretation} at all costs.; Comment: Latex ; 23 pages ; 3 figures. Presentation changed and Misprints corrected

The realization of the wave function collapse in the linguistic interpretation of quantum mechanics

Ishikawa, Shiro
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.5%
Recently I proposed the linguistic interpretation of quantum mechanics, which is characterized as the linguistic turn of the Copenhagen interpretation of quantum mechanics. This turn from physics to language does not only extend quantum theory to classical theory but also yield the quantum mechanical world view. Although the wave function collapse is prohibited in the linguistic interpretation, in this paper I show that the phenomenon like wave function collapse can be realized in the linguistic interpretation. And furthermore, I propose the justification of the von Neumann-L\"uders projection postulate. After all, I conclude that the wave function collapse should not be adopted in the Copenhagen interpretation.; Comment: 5 pages

Copenhagen Interpretation of Quantum Theory and the Measurement Problem

Kober, Martin
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.57%
The Copenhagen interpretation of quantum theory is investigated from a philosophical point of view. It is justified the opinion that the philosophical attitude the Copenhagen interpretation is based on is in principle inevitable for a real comprehension of quantum theory. This attitude is mainly related to epistemological arguments. However, the measurement problem often seems not to be treated clearly enough within the interpretation. By referring to the property of the necessity to use macroscopic measurement instruments obeying classical concepts it is made the attempt to solve the measurement problem. According to this consideration the indeterministic character of quantum theory seems to have its origin in a lack of knowledge and thus it appears in a similar but more principle way than in statistical mechanics. It is emphasized the ontological character of the uncertainty relation and the related non locality of quantum theory suggesting that the existence of a position space is not as fundamental as the assumptions of general quantum theory.; Comment: 9 pages

From Copenhagen to neo-Copenhagen interpretation

de Muynck, Willem M.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.79%
Positive and negative features of the Copenhagen interpretation are discussed. As positive features can be mentioned its pragmatism and its awareness of the crucial role of measurement. However, the main part of the contribution is devoted to the negative features, to wit, its pragmatism (once again), its confounding of preparation and measurement, its classical account of measurement, its completeness claims, the ambiguity of its notion of correspondence, its confused notion of complementarity. It is demonstrated how confusions and paradoxes stemming from the negative features of the Copenhagen interpretation can be dealt with in an amended interpretation, to be referred to as neo-Copenhagen interpretation', in which the role of the measuring instrument is taken seriously by recognizing the quantum mechanical character of its interaction with the microscopic object. The ensuing necessity of extending the notion of a quantum mechanical observable from the Hermitian operator of the standard formalism to the positive operator-valued measure of a generalized formalism is demonstrated to yield a sound mathematical basis for a transition from the Copenhagen contextualistic-realist interpretation to the neo-Copenhagen empiricist one. Applications to the uncertainty relations and to the Bell inequalities are briefly discussed.; Comment: To be published in the Proceedings of the Conference: Quantum Theory - 4...

Popper's experiment and the Copenhagen interpretation

Peres, Asher
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.34%
Popper conceived an experiment whose analysis led to a result that he deemed absurd. Popper wrote that his reasoning was based on the Copenhagen interpretation and therefore invalidated the latter. Actually, Popper's argument involves counterfactual reasoning and violates Bohr's complementarity principle. The absurdity of Popper's result only confirms Bohr's approach.; Comment: 13 pages LaTeX, one separate page of figures, submitted to SHPMP

Copenhagen Quantum Mechanics

Hollowood, Timothy J.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.53%
In our quantum mechanics courses, measurement is usually taught in passing, as an ad-hoc procedure involving the ugly collapse of the wave function. No wonder we search for more satisfying alternatives to the Copenhagen interpretation. But this overlooks the fact that the approach fits very well with modern measurement theory with its notions of the conditioned state and quantum trajectory. In addition, what we know of as the Copenhagen interpretation is a later 1950's development and some of the earlier pioneers like Bohr did not talk of wave function collapse. In fact, if one takes these earlier ideas and mixes them with later insights of decoherence, a much more satisfying version of Copenhagen quantum mechanics emerges, one for which the collapse of the wave function is seen to be a harmless book keeping device. Along the way, we explain why chaotic systems lead to wave functions that spread out quickly on macroscopic scales implying that Schrodinger cat states are the norm rather than curiosities generated in physicists' laboratories. We then describe how the conditioned state of a quantum system depends crucially on how the system is monitored illustrating this with the example of a decaying atom monitored with a time of arrival photon detector...

The Copenhagen Interpretation as an Emergent Phenomenon

Hollowood, Timothy J.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.6%
The Copenhagen interpretation has been remarkably successful but seems at odds with the underlying linearity of quantum mechanics. We show how it can emerge in a simple way from the underlying microscopic quantum world governed by Schrodinger's equation without the need for observers or their brains. In order to achieve this, we assemble pieces of various pre-existing ideas. Firstly, we adopt a relational approach and use the eigenvectors of the reduced density matrix of a quantum sub-system, or equivalently the Schmidt decomposition, to define the internal state' of a sub-system. Previous work has identified serious objections to such an interpretation because it apparently leads to macroscopic superpositions and physically unacceptable instabilities near degeneracies. We show that both these problems are solved if the sub-system consists of a large number of coarse grained degrees of freedom as one expects in order to make contact with the classical world. We further argue that coarse graining is a necessary ingredient because measuring devices have both finite spatial and temporal resolutions. What results is an interpretation in which both decoherence and coarse graining play key roles and from which the rules of the Copenhagen interpretation are seen to emerge in realistic situations that include the measurement of the position of a particle and a decay process.; Comment: 33 pages...

The Copenhagen interpretation, and pragmatism

de Muynck, Willem M.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.34%
In the past both instrumentalism and empiricism have inspired certain pragmatic elements into the Copenhagen interpretation of quantum mechanics. The relation of such pragmatisms with the correspondence principle is discussed. It is argued that neither Bohr nor Heisenberg did take correspondence' in one of these forms, and that it, in particular, was Bohr's classical attitude which caused him to apply in an inconsistent way his correspondence principle to the Einstein-Podolsky-Rosen experiment, thus causing much confusion. It is demonstrated that an empiricist pragmatism is conducive to an explanation of violation of the Bell inequalities as a consequence of complementarity' in the sense of mutual disturbance in a joint nonideal measurement of incompatible observables' rather than as being caused by nonlocal influences'.; Comment: Contribution to the Conference on Pragmatism & quantum mechanics'', CREA, Ecole Polytechnique & CNRS, Paris, February 22-23, 2007

Which causality? Differences between the trajectory and Copenhagen analyses of an impulsive perturbation

Floyd, Edward R.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.58%
The trajectory and Copenhagen representations render different predictions for impulse perturbations. The different predictions are due to the different roles that causality plays in the trajectory and Copenhagen interpretations. We investigate a small perturbing impulse acting on the ground state of an infinitely deep square well. For the two representations, the first-order perturbation calculations for the temporal change in energy differ. This temporal change in energy for the trajectory representation is dependent upon the microstate of the wave function. We show that even under Copenhagen epistemology, the two representations predict different theoretical results.; Comment: 12 pages of LaTeX 2.09. No figures. Errata [Int. J. Mod. Phys. A16 (2001) 2447] appended to end. The errata strengthen the findings. Key words: causality, hidden variables, trajectory interpretation, Copenhagen interpretation, interpretations of quantum mechanics, impulse perturbations

The Interpretation of Quantum Mechanics: Many Worlds or Many Words?

Tegmark, Max
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.48%
As cutting-edge experiments display ever more extreme forms of non-classical behavior, the prevailing view on the interpretation of quantum mechanics appears to be gradually changing. A (highly unscientific) poll taken at the 1997 UMBC quantum mechanics workshop gave the once all-dominant Copenhagen interpretation less than half of the votes. The Many Worlds interpretation (MWI) scored second, comfortably ahead of the Consistent Histories and Bohm interpretations. It is argued that since all the above-mentioned approaches to nonrelativistic quantum mechanics give identical cookbook prescriptions for how to calculate things in practice, practical-minded experimentalists, who have traditionally adopted the shut-up-and-calculate interpretation'', typically show little interest in whether cozy classical concepts are in fact real in some untestable metaphysical sense or merely the way we subjectively perceive a mathematically simpler world where the Schrodinger equation describes everything - and that they are therefore becoming less bothered by a profusion of worlds than by a profusion of words. Common objections to the MWI are discussed. It is argued that when environment-induced decoherence is taken into account, the experimental predictions of the MWI are identical to those of the Copenhagen interpretation except for an experiment involving a Byzantine form of quantum suicide''. This makes the choice between them purely a matter of taste...

The Copenhagen Interpretation Born Again

Hollowood, Timothy J.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.34%
An approach to quantum mechanics is developed which makes the Heisenberg cut between the deterministic microscopic quantum world and the partly deterministic, partly stochastic macroscopic world explicit. The microscopic system evolves according to the Schrodinger equation with stochastic behaviour arising when the system is probed by a set of coarse grained macroscopic observables whose resolution scale defines the Heisenberg cut. The resulting stochastic process can account for the different facets of the classical limit: Newton's laws (ergodicity broken); statistical mechanics of thermal ensembles (ergodic); and solve the measurement problem (partial ergodicity breaking). In particular, the usual rules of the Copenhagen interpretation, like the Born rule, emerge, along with completely local descriptions of EPR type experiments. The formalism also re-introduces a dynamical picture of equilibration and thermalization in quantum statistical mechanics and provides insight into how classical statistical mechanics can arise in the classical limit and in a way that alleviates various conceptual problems.; Comment: 44 pages, updated references and typos corrected

Towards a Neo-Copenhagen Interpretation of Quantum Mechanics

de Muynck, W. M.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.67%
The Copenhagen interpretation is critically considered. A number of ambiguities, inconsistencies and confusions are discussed. It is argued that it is possible to purge the interpretation so as to obtain a consistent and reasonable way to interpret the mathematical formalism of quantum mechanics, which is in agreement with the way this theory is dealt with in experimental practice. In particular, the essential role attributed by the Copenhagen interpretation to measurement is acknowledged. For this reason it is proposed to refer to it as a neo-Copenhagen interpretation.

Justifying the Classical-Quantum Divide of the Copenhagen Interpretation

Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.6%
Perhaps the most significant drawback, which the Copenhagen interpretation (still the most popular interpretation of quantum theory) suffers from, is the classical-quantum divide between the large classical systems that carry out measurements and the small quantum systems that they measure. So, an "ideal" alternative interpretation of quantum theory would either eliminate this divide or justify it in some reasonable way. The present paper demonstrates that it is possible to justify the classical-quantum dualism of the Copenhagen interpretation by way of the analysis of the time complexity of Schrodinger's equation.; Comment: 9 pages; Latex

Popper's experiment, Copenhagen Interpretation and Nonlocality

Qureshi, Tabish
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.34%
A thought experiment, proposed by Karl Popper, which has been experimentally realized recently, is critically examined. A basic flaw in Popper's argument which has also been prevailing in subsequent debates, is pointed out. It is shown that Popper's experiment can be understood easily within the Copenhagen interpretation of quantum mechanics. An alternate experiment, based on discrete variables, is proposed, which constitutes Popper's test in a clearer way. It refutes the argument of absence of nonlocality in quantum mechanics.; Comment: Thoroughly revised. To appear in Int. J. Quantum Information

The double-slit quantum eraser experiments and Hardy's paradox in the quantum linguistic interpretation

Ishikawa, Shiro
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.64%
Recently we proposed the linguistic interpretation of quantum mechanics (called quantum and classical measurement theory), which was characterized as a kind of metaphysical and linguistic turn of the Copenhagen interpretation. This turn from physics to language does not only extend quantum theory to classical systems but also yield the quantum mechanical world view (i.e., quantum philosophy or quantum language). The purpose of this paper is to formulate the double-slit experiment, the quantum eraser experiment, Wheeler's delayed choice experiment, Hardy's paradox and the three boxes paradox (the weak value associated with a weak measurement due to Aharonov, et al.) in the linguistic interpretation of quantum mechanics. Through these arguments, we assert that the linguistic interpretation is just the final version of so called Copenhagen interpretation. And therefore, we conclude that the Copenhagen interpretation does not belong to physics (i.e., the realistic world view) but the linguistic world view.; Comment: arXiv admin note: text overlap with arXiv:1404.2664

Werner Heisenberg e a Interpretação de Copenhague: a filosofia platônica e a consolidação da teoria quântica

Leite, Anderson; Simon, Samuel