Showing papers on "Consistent histories published in 1990"
TL;DR: The quantization of a simple dynamical system in which a unitary time evolution appears only within a certain approximation is studied in detail.
Abstract: The quantization of a simple dynamical system in which a unitary time evolution appears only within a certain approximation is studied in detail. The probabilistic interpretation of quantum mechanics in the regimes in which time is not defined is discussed and shown to be consistent.
313 citations
TL;DR: In this article, a reformulation of the Dirac theory shows that thezitterbewegung need not be attributed to interference between positive and negative energy states as originally proposed by Schroedinger.
Abstract: Thezitterbewegung is a local circulatory motion of the electron presumed to be the basis of the electron spin and magnetic moment. A reformulation of the Dirac theory shows that thezitterbewegung need not be attributed to interference between positive and negative energy states as originally proposed by Schroedinger. Rather, it provides a physical interpretation for the complex phase factor in the Dirac wave function generally. Moreover, it extends to a coherent physical interpretation of the entire Dirac theory, and it implies azitterbewegung interpretation for the Schroedinger theory as well.
247 citations
TL;DR: In this article, a new interpretation of quantum mechanics is proposed, relying upon several important results that have been made during the last decade or so, including Griffiths histories describing in detail the properties of a quantum system and submitted to consistency conditions allowing a clearcut distinction between meaningful and meaningless properties.
146 citations
Book•
01 Jan 1990
TL;DR: The measurement process in the individual interpretation of quantum mechanics and the theory of measurement by R. Fukuda and A.M. Zeilinger are discussed in detail in this article.
Abstract: Where is the problem? by J.M. Levy-Leblond Experiment and quantum measurement theory by A. Zeilinger A consistent interpretation of quantum mechanics. The measurement process in the individual interpretation of quantum mechanics by H. Primas Principle of stationarity in the action functional and the theory of measurement by R. Fukuda Quantum (statistical) mechanics, measurement and information by R. Balian State vector collapse as a classical statistical effect of measurement by M. Cini and M. Serva Consecutive quantum measurements by A. Peres No-collapse versions of quantum mechanics by Y. Ben-Dov An attempt to understand the many-worlds interpretation of quantum theory by E.J. Squires Uncertainty and measurement by P.T. Landsberg Author Index
29 citations
24 citations
TL;DR: In this article, the authors revive an old proposal of Zeh (1986) for the preferred basis in the many-worlds interpretation of quantum mechanics, which reduces to the eigenvalue problems for density matrices of subsystems splitting the quantum system into the observer and the observable counterpart.
Abstract: The authors revive an old proposal of Zeh (1986) for the preferred basis in the many-worlds interpretation of quantum mechanics. The algorithm for this basis reduces to the eigenvalue problems for density matrices of subsystems splitting the quantum system into the observer and the observable counterpart. A semiclassical calculational method for these eigenvalue problems is developed and the dynamical properties of the preferred basis are investigated. Applications of this proposal to quantum cosmology are discussed.
20 citations
TL;DR: This paper digests technical commonplaces of quantum field theory to present an informal interpretation of the theory by emphasizing its connections with the harmonic oscillator, and argues that, in important respects, interpretive problems of Quantum field theory are problems the authors know well from conventional quantum mechanics.
Abstract: This paper digests technical commonplaces of quantum field theory to present an informal interpretation of the theory by emphasizing its connections with the harmonic oscillator. The resulting "harmonic oscillator interpretation" enables newcomers to the subject to get some intuitive feel for the theory. The interpretation clarifies how the theory relates to observation and to quantum mechanical problems connected with observation. Finally the interpretation moves some way towards helping us see what the theory comes to physically. The paper also argues that, in important respects, interpretive problems of quantum field theory are problems we know well from conventional quantum mechanics. An important exception concerns extending the puzzles surrounding the superposition of properties in conventional quantum mechanics to an exactly parallel notion of superposition of particles. Conventional quantum mechanics seems incompatible with a classical notion of property on which all quantities always have definit...
18 citations
01 Jan 1990
TL;DR: In this article, Kochen has suggested an interpretation of quantum mechanics in which he denies that wavepackets ever collapse, while affirming that measurements have definite results, and this interpretation is untenable.
Abstract: Kochen has suggested an interpretation of quantum mechanics in which he denies that wavepackets ever collapse, while affirming that measurements have definite results. In this paper I attempt to show that his interpretation is untenable. I then suggest ways in which to construct similar, but more satisfactory, hidden variable interpretations.
16 citations
TL;DR: The present paper shows that an inconsistency arises between the conventional interpretation of CSM which presupposes objectively existing Newtonian trajectories, and the standard interpretation of QM, and concludes that the latter needs revisiting.
Abstract: According to the standard interpretation of quantum mechanics (QM), no meaning can be assigned to the statement that a particle has a precise value of any one of the variables describing its physical propertes before having interacted with a suitable measuring instrument. On the other hand, it is well known that QM tends to classical statistical mechanics (CSM) when a suitable classical limit is performed. One may ask therefore how is it that in this limit, the statement, meaningless in QM, that a given variable has always a precise value independently of having been measured, gradually becomes meaningful. In other words, one may ask how can it be that QM, which is a theory describing the intrinsically probabilistic properties of a quantum object, becomes a statistical theory describing a probabilistic knowledge of intrinsically well determined properties of classical objects.
13 citations
17 Oct 1990
TL;DR: In this paper, it is argued that quantum measurements do pose a problem, within the context created by the fundamental aim of science, which is identified as the construction of a cohesive, comprehensive, and rationally coherent idea of the nature of the world in which we live Models of nature are divided into two classes: (1) those in which there is a selection process that, for any possible measurement, would, if that measurement were to be performed, pick out one single outcome, and (2), all others.
Abstract: It is argued that quantum measurements do pose a problem, within the context created by the fundamental aim of science, which is identified as the construction of a cohesive, comprehensive, and rationally coherent idea of the nature of the world in which we live Models of nature are divided into two classes: (1), those in which there is a selection process that, for any possible measurement, would, if that measurement were to be performed, pick out one single outcome, and, (2), all others It is proved that any model of class that reproduces the predictions of quantum theory must violate the condition that there be no faster-than-light influences of any kind This result is used to motivate the study of models in which unitary evolution is maintained and there is no selection of unique outcomes A consideration of ontic probabilities, historical records, and the form of the mind-brain connection leads to an elaboration of the Everett many-worlds interpretation that appears to provide the basis of satisfactory solution of the measurement problem 18 refs
11 citations
TL;DR: Einstein regarded the quantum theory as not only incomplete, but also fundamentally inadequate as mentioned in this paper, and he believed that the only reasonable interpretation of the quantum formalism was an ensemble interpretation, but he also thought that this interpretation and others were incomplete and irremediably inadequate, because they failed to describe the objective, real states of individual systems.
Abstract: Einstein’s opposition to the quantum theory is well known to physicists, but his reasons for being dissatisfied are not. Einstein regarded the theory as not only incomplete, but as fundamentally inadequate. He believed that the only reasonable interpretation of the quantum formalism was an ‘‘ensemble interpretation,’’ but he also thought that this interpretation and others were incomplete and irremediably inadequate, because they failed to describe the objective, real states of individual systems. He hoped, and expected, that a better theory would be developed—one expressed in terms of individuals having their own real states and from which the quantum theory could be recovered as an approximation.
TL;DR: In this article, the basic ideas of quantum mechanics are developed from intuitive first principles to the point where one can connect with more traditional treatments of quantum physics, such as the Schrodinger equation and the position-momentum uncertainty relation.
Abstract: This article is a ‘‘sampler,’’ which shows how quantum mechanics may be presented to students in a way that makes apparent how natural quantum mechanics is as a description of the world. The mathematical machinery of Hilbert space, the idea of representing observables by operators, the Schrodinger equation, and the position‐momentum uncertainty relation all follow from natural assumptions that students can readily accept. The basic ideas of quantum mechanics are developed from intuitive first principles to the point where one can connect with more traditional treatments of quantum mechanics.
TL;DR: In this paper, a discussion of recent ideas relating quantum mechanics, gravitation, and psychological phenomena has been carried out by a theoretical physicist currently working on physical aspects of consciousness, mind-matter relationships, and mind-body interactions.
Abstract: This note was written by a theoretical physicist currently working on physical aspects of consciousness, mind-matter relationships, and mind-body interactions. My purpose here is to inform the readers of this journal, in not too technical terms, of some recent ideas relating quantum mechanics, gravitation, and psychological phenomena. Attempts to relate the nature of consciousness to quantum mechanics have been known almost from the be+g of quantum mechanics. For an extended discussion and earlier references see, e.g., Stapp (1982). The common thread of the majority of the suggested hypotheses linking consciousness to a quantum level of description is a drawing of a between the spontaneous localization of mental patterns and (spontaneous or induced) reduction of the wave function in quantum mechanics. The latter essentially means that quantum systems are inherently described in probabilistic terms and any external observation "reduces" the manyfold of all potential possibilia to a single given realization. Interpretation of this process is one of the most difficult and controversial topics of quantum mechanics since in quantum mechanics it is thus far essentially impossible to demarcate unambiguously the "observer" from the quantum system itself. Despite that gravitational effects are usually deemed to be too weak at atomic level, a few authors recently discussed gravity as an inherent route used by nature to achieve an "automatic" spontaneous reduction of the wave functions of extended objects. In his recent book, Roger Penrose (1989) looks for the possible connections between consciousness, quantum mechanical reduction and gravitational phenomena. To simplify, the essence of these hypotheses is that subtle gravitational effects at the atomic-molecular level "lock" the brain into a particular mental state, thereby providing the "materialization" of the potential (quantum) mental image by the route similar to the reduction of the wave function in quantum mechanics. Isotopic diversity of chemical elements can substantially contribute to this picture, as well as to life processes in general (Berezin, 1988). Since gravity is a mass-sensitive effect, the fact that different stable isotopes of the same element (e.g., carbon, oxygen, nitrogen) have different atomic masses may affect the path of mental processing.
TL;DR: In this article, it is shown that this view does not stand on solid ground and serious objections can be raised against the (often implicit) view that identifies the physical relation of compatibility preserved by Luders' rule with the relation of simultaneous measurability.
Abstract: An interpretation of quantum mechanics that rejects hidden variables has to say something about the way measurement can be understood as a transformation on states of individual systems, and that leads to the core of the interpretive problems posed by Luders' projection rule: What, if any, is its physical content? In this paper I explore one suggestion which is implicit in usual interpretations of the rule and show that this view does not stand on solid ground. In the process, important aspects of the role played by the projection postulate in the conceptual structure of quantum mechanics will be clarified. It will be shown in particular that serious objections can be raised against the (often implicit) view that identifies the physical relation of compatibility preserved by Luders' rule with the relation of simultaneous measurability.
TL;DR: In this paper, the authors discussed the quantum 'paradoxes' from a different viewpoint with the aim of demystifying the theory, shifting from an epistemological viewpoint (as exemplified by the "probability interpretation") to an ontological one (the description of matter by physical fields).
Abstract: A number of books have appeared purporting to explain quantum mechanics to the general public These books have put considerable emphasis on so-called quantum 'paradoxes', using them to portray the quantum theory as mysterious or 'spooky' The author discusses these 'paradoxes' from a different viewpoint with the aim of demystifying the theory Emphasis is shifted from an epistemological viewpoint (as exemplified by the 'probability interpretation') to an ontological one (the description of matter by physical fields) Difficulties in reconciling the probability interpretation with relativity are noted, and the importance of phase coherence, which is inadequately treated in the probability interpretation, is emphasised In the light of such as approach, the 'paradoxes' are resolved
01 Jan 1990
TL;DR: In this paper, the logical structure given by four axioms of Mackey [3] in the set of propositions of Quantum Mechanics is presented, and the equivalence relation (PropRel(Q)) is considered, where the structure of quotient space and the properties of equivalence relations, classes and partitions are studied.
Abstract: Summary. In this article we present the logical structure given by four axioms of Mackey [3] in the set of propositions of Quantum Mechanics. The equivalence relation (PropRel(Q)) in the set of propositions (Prop Q) for given Quantum Mechanics Q is considered. The main text for this article is [6] where the structure of quotient space and the properties of equivalence relations, classes and partitions are studied.