We make a first attempt to axiomatically formulate the Montevideo interpretation of quantummechanics. In this interpretation environmental decoherence is supplemented with loss of coherence due to the use of realistic clocks to measure time to solve the measurement problem. The resulting formulation is framed entirely in terms of quantum objects without having to invoke the existence of measurable classical quantities like the time in ordinary quantummechanics. The formulation eliminates any privileged role to the (...) measurement process giving an objective definition of when an event occurs in a system. (shrink)
What is quantummechanics about? The most natural way to interpret quantummechanics realistically as a theory about the world might seem to be what is called wave function ontology: the view according to which the wave function mathematically represents in a complete way fundamentally all there is in the world. Erwin Schroedinger was one of the first proponents of such a view, but he dismissed it after he realized it led to macroscopic superpositions (if the (...) wave function evolves in time according to the equations that has his name). The Many-Worlds interpretation1 accepts the existence of such macroscopic superpositions but takes it that they can never be observed. Superposed objects and superposed observers split together in different worlds of the type of the one we appear to live in. For these who, like Schroedinger, think that macroscopic superpositions are a problem, the common wisdom is that there are two alternative views: "Either the wave function, as given by the Schroedinger equation, is not everything, or is not right" [Bell 1987]. The deBroglie-Bohm theory, now commonly known as Bohmian Mechanics, takes the first option: the description provided by a Schroedinger-evolving wave function is supplemented by the information provided by the configuration of the particles. The second possibility consists in assuming that, while the wave function provides the complete description of the system, its temporal evolution is not given by the Schroedinger equation. Rather, the usual Schroedinger evolution is interrupted by random and sudden "collapses". The most promising theory of this kind is the GRW theory, named after the scientists that developed it: Gian Carlo Ghirardi, Alberto Rimini and Tullio Weber.. It seems tempting to think that in GRW we can take the wave function ontologically seriously and avoid the problem of macroscopic superpositions just allowing for quantum jumps. In this paper we will argue that such "bare" wave function ontology is not possible, neither for GRW nor for any other quantum theory: quantummechanics cannot be about the wave function simpliciter. That is, we need more structure than the one provided by the wave function. As a response, quantum theories about the wave function can be supplemented with structure, without taking it as an additional ontology. We argue in reply that such "dressed-up" versions of wave function ontology are not sensible, since they compromise the acceptability of the theory as a satisfactory fundamental physical theory. Therefore we maintain that: 1- Strictly speaking, it is not possible to interpret quantum theories as theories about the wave function; 2- Even if the wave function is supplemented by additional non-ontological structures, there are reasons not to take the resulting theory seriously. Moreover, we will argue that any of the traditional responses to the measurement problem of quantummechanics (Bohmian mechanics, GRW and Many-Worlds), contrarily to what commonly believed, share a common structure. That is, we maintain that: 3- All quantum theories should be regarded as theories in which physical objects are constituted by a primitive ontology. The primitive ontology is mathematically represented in the theory by a mathematical entity in three-dimensional space, or space-time. (shrink)
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 quantummechanics, 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. (shrink)
The book Heisenberg and the Interpretation of QuantumMechanics—The Physicist as Philosopher, by Kristian Camilleri is critically reviewed. The work details Heisenberg’s philosophical development from an early positivist commitment towards a later philosophy of language. It is of interest to researchers and graduate students in the history and philosophy of quantummechanics.
It has been traditionally considered that QuantumMechanics has two conceptual kinds of problems, namely, those related with local-realism and the so-called measurement problem. That is, the uniqueness of the result when we make a measurement. With the development of what is called generically Quantum Information Theory, a new form of the Copenhagen interpretation of the formalism has taken shape.(1) In this paper, we will analyse if this information interpretation is able to clarify these old problems. Although (...) this interpretation seems to be the most promising approach we have, we have reached the conclusion that the answer cannot be given in a positive and clear way yet. (shrink)
We study the process of observation (measurement), within the framework of a “perspectival” (“relational,” “relative state”) version of the modal interpretation of quantummechanics. We show that if we assume certain features of discreteness and determinism in the operation of the measuring device (which could be a part of the observer's nerve system), this gives rise to classical characteristics of the observed properties, in the first place to spatial localization. We investigate to what extent semi-classical behavior of the (...) object system itself (as opposed to the observational system) is needed for the emergence of classicality. Decoherence is an essential element in the mechanism of observation that we assume, but it turns out that in our approach no environment-induced decoherence on the level of the object system is required for the emergence of classical properties. (shrink)
It is argued that the so-called minimal statistical interpretation of quantummechanics does not completely resolve the measurement problem in that this view is unable to show that quantjum mechanics can dispense with classical physics when it comes to a treatment of the measuring interaction. It is suggested that the view that quantummechanics applies to individual systems should not be too hastily abandoned, in that this view gives perhaps the best hope of leading to (...) a version of quantummechanics which does provide a complete solution to the measurement problem. (shrink)
This paper investigates the possibiity of developing a fully micro realistic version of elementary quantummechanics. I argue that it is highly desirable to develop such a version of quantummechanics, and that the failure of all current versions and interpretations of quantummechanics to constitute micro realistic theories is at the root of many of the interpretative problems associated with quantummechanics, in particular the problem of measurement. I put forward (...) a propensity micro realistic version of quantummechanics, and suggest how it might be possible to discriminate, on expermental grounds, between this theory and other versions of quantummechanics. (shrink)
Two of the main interpretative problems in quantummechanics are the so-called measurement problem and the question of the compatibility of quantummechanics with relativity theory. Modal interpretations of quantummechanics were designed to solve both of these problems. They are no-collapse (typically) indeterministic interpretations of quantummechanics that supplement the orthodox state description of physical systems by a set of possessed properties that is supposed to be rich enough to (...) account for the classical-like behavior of macroscopic systems, but sufficiently restricted so as to avoid the no-hidden-variables theorems. But, as recent no-go theorems suggest, current modal interpretations are incompatible with relativity. In this paper, we suggest a strategy for circumventing these theorems. We then show how this strategy could naturally be integrated in a relational version of the modal interpretation, where quantum-mechanical states assign relational rather than intrinsic properties. (shrink)
This book examines in detail two of the fundamental questions raised by quantummechanics. First, is the world indeterministic? Second, are there connections between spatially separated objects? In the first part, the author examines several interpretations, focusing on how each proposes to solve the measurement problem and on how each treats probability. In the second part, the relationship between probability (specifically determinism and indeterminism) and non-locality is examined, and it is argued that there is a non-trivial relationship (...) between probability and non-locality. The author then re-examines some of the interpretations of part one of the book in the light of this argument, and considers how they fare with regard to locality and Lorentz invariance. The book will appeal to anyone with an interest in the interpretation of quantummechanics, including researchers in the philosophy of physics and theoretical physics, as well as graduate students in those fields. (shrink)
We argue that certain types of many minds (and many worlds) interpretations of quantummechanics, e.g. Lockwood ([1996a]), Deutsch () do not provide a coherent interpretation of the quantum mechanical probabilistic algorithm. By contrast, in Albert and Loewer's () version of the many minds interpretation, there is a coherent interpretation of the quantum mechanical probabilities. We consider Albert and Loewer's probability interpretation in the context of Bell-type and GHZ-type states and argue that it implies a (...) certain (weak) form of nonlocality. 1 Introduction 2 Albert and Loewer's interpretation 3 Probabilities in Lockwood's interpretation 4 Sets of minds and their correlations 5 Many minds and GHZ. (shrink)
We argue that certain types of many minds (and many worlds) interpretations of quantummechanics, e.g. Lockwood ([1996a]), Deutsch () do not provide a coherent interpretation of the quantum mechanical probabilistic algorithm. By contrast, in Albert and Loewer's () version of the many minds interpretation, there is a coherent interpretation of the quantum mechanical probabilities. We consider Albert and Loewer's probability interpretation in the context of Bell-type and GHZ-type states and argue that it implies a (...) certain (weak) form of nonlocality. (shrink)
We prove a uniqueness theorem showing that, subject to certain natural constraints, all 'no collapse' interpretations of quantummechanics can be uniquely characterized and reduced to the choice of a particular preferred observable as determine (definite, sharp). We show how certain versions of the modal interpretation, Bohm's 'causal' interpretation, Bohr's complementarity interpretation, and the orthodox (Dirac-von Neumann) interpretation without the projection postulate can be recovered from the theorem. Bohr's complementarity and Einstein's realism appear as two quite different (...) proposals for selecting the preferred determinate observable--either settled pragmatically by what we choose to observe, or fixed once and for all, as the Einsteinian realist would require, in which case the preferred observable is a 'beable' in Bell's sense, as in Bohm's interpretation (where the preferred observable is position in configuration space). (shrink)
The aim of this article is twofold. Recently, Lewis has presented an argument, now known as the "counting anomaly", that the spontaneous localization approach to quantummechanics, suggested by Ghirardi, Rimini, and Weber, implies that arithmetic does not apply to ordinary macroscopic objects. I will take this argument as the starting point for a discussion of the property structure of realist collapse interpretations of quantummechanics in general. At the end of this I present a (...) proof of the fact that the composition principle, which holds true in standard quantummechanics, fails in all realist collapse interpretations. On the basis of this result I reconsider the counting anomaly and show that what lies at the heart of the anomaly is the failure to appreciate the peculiarities of the property structure of such interpretations. Once this flaw is uncovered, the anomaly vanishes. (shrink)
Modal interpretations have the ambition to construe quantummechanics as an objective, man-independent description of physical reality. Their second leading idea is probabilism: quantummechanics does not completely fix physical reality but yields probabilities. In working out these ideas an important motif is to stay close to the standard formalism of quantummechanics and to refrain from introducing new structure by hand. In this paper we explain how this programme can be made concrete. (...) In particular, we show that the Born probability rule, and sets of definite-valued observables to which the Born probabilities pertain, can be uniquely defined from the quantum state and Hilbert space structure. We discuss the status of probability in modal interpretations, and to this end we make a comparison with many-worlds alternatives. An overall point that we stress is that the modal ideas define a general framework and research programme rather than one definite and finished interpretation. (shrink)
Modal interpretations take quantummechanics as a theory which assigns at all times definite values to magnitudes of quantum systems. In the case of single systems, modal interpretations manage to do so without falling prey to the Kochen and Specker no-go theorem, because they assign values only to a limited set of magnitudes. In this paper I present two further no-go theorems which prove that two modal interpretations become nevertheless problematic when applied to more (...) than one system. The first theorem proves that the modal interpretation proposed by Kochen and by Dieks cannot correlate the values simultaneously assigned to three systems. The second and new theorem proves that the atomic modal interpretation proposed by Bacciagaluppi and Dickson and by Dieks cannot correlate the values simultaneously and sequentially assigned to two systems if one assumes that these correlations are uniquely related to the dynamics of the state of the systems. (shrink)
I consider various experiments related to the so-called “macroscopic quantum coherence” experiment, which are probably at present in the class of “thought” experiment but are likely to become realistic in the next few decades. I explore the way in which outcomes consistent with the predictions of quantummechanics would be interpreted by an adherent of, respectively, the Copenhagen, statistical, and Bohmian interpretations of the formalism.
In this paper I consider the problem of interpreting quantummechanics. I argue that this problem has evolved in part into the problem of selecting tenable interpretations from a set of available interpretations. We lack the means to make this selection. There is consensus that interpretations should be consistent and empirically adequate. But these conditions are not particularly discriminative. Other conditions may be discriminative but are not generally accepted. I propose two new conditions for selecting (...) tenable interpretations, motivated by the use of quantummechanics in technology. The first requires that interpretations ascribe the physical properties to technical artefacts that are entailed by the ascription of technical functions to those artefacts. The second requires that they ascribe the physical properties represented by engineering sketches of those artefacts. I consider the example of quantum teleportation in some detail. Introduction The problem of interpreting quantummechanics Technical functions Decoders in quantum teleportation Engineering sketches Conclusions Appendix: Quantum teleportation. (shrink)
Orthodox quantummechanics includes the principle that an observable of a system possesses a well-defined value if and only if the presence of that value in the system is certain to be confirmed on measurement. Modal interpretations reject the controversial ‘only if’ half of this principle to secure definite outcomes for quantum measurements that leave the apparatus entangled with the object it has measured. However, using a result that turns on the construction of a Kochen–Specker contradiction, (...) I argue that modal interpretations cannot deliver a metaphysically tenable conception of properties in quantummechanics unless they also abandon the less controversial ‘if’ half of the orthodox principle. (shrink)
This paper proposes a logic, motivated by modal interpretations, in which every quantummechanics propositions has a truth-value. This logic is completely classical, hence violates the conditions of the Kochen-Specker theorem. It is shown how the violation occurs, and it is argued that this violation is a natural and acceptable consequence of modal interpretations. It is shown that despite its classicality, the proposed logic is empirically indistinguishable from quantum logic.
Modal interpretations constitute a particular approach to associating dynamical variables with physical systems in quantummechanics. Given the “quantum logical” constraints that are typically adopted by such interpretations, only certain sets of variables can be taken to be simultaneously definite-valued, and only certain sets of values can be ascribed to these variables at a given time. Moreover, each allowable set of variables and values can be uniquely specified by a single “core” projector in the Hilbert (...) space associated with the system. In general, the core projector can be one of several possibilities at a given time. In most previous modal interpretations, the different possible core projectors have formed an orthogonal set. This paper investigates the possibility of adopting a non-orthogonal set. It is demonstrated that such non-orthogonality is required if measurements for which the outcome can be predicted with probability 1 are to reveal the pre-existing value of the variable measured, an assumption which has traditionally constituted a strong motivation for the modal approach. The existing framework for modal interpretations is generalized to explicitly accommodate non-orthogonal core projectors. (shrink)
Although quantummechanics has significantly advanced our understanding of the physical world, it has also been a source of great confusion. Myriad interpretations, and interpretations of interpretations, have been proposed to try and explain away the seeming inconsistencies which lie at the heart of quantummechanics. All of these attempts at interpretation center on the seemingly intractable measurement problem. In this essay I argue that a number of interpretations of quantum (...) class='Hi'>mechanics are plagued by inadequate and misleading assumptions about the observer. These assumptions are based on a naïve “folk conception” of the observer. In discussing two phenomena studied in modern cognitive science, I will argue for a rejection of the naïve conception of the observer and adopt a more sophisticated view which offers a significant interpretational payoff. I argue that although the measurement problem in quantummechanics appears to be a scientific problem requiring a scientific solution, it is plausible that the problem might be a pseudo-problem resulting from a conceptual confusion. The conceptual confusion is caused by naïve assumptions about the nature of the observer.1 Based on these arguments I will reevaluate a number of interpretations and assess the role of philosophy in interpreting quantummechanics. (shrink)
Dualistic interpretations attempt to solve the measurement problem of quantummechanics by postulating the existence of non-physical minds, and by giving a suitable dynamical equation for how these minds evolve. I consider the relative merits of three extant dualistic interpretations (Albert and Loewer’s single-mind and many-minds interpretations, and Squires’ interpretation), and I defend Squires’ interpretation as preferable to the Albert/Loewerinterpretations. I also argue that, for all three of these interpretations, the (...) minds evolve independently of the physical universe, and hence render the physical universe otiose; the interpretations are better viewed as supporting not dualism, but mental monism. (shrink)
In this paper we unravel the connection between the quantum mechanical formalism and the Central limit theorem (CLT). We proceed to connect the results coming from this theorem with the derivations of the Schrödinger equation from the Liouville equation, presented by ourselves in other papers. In those papers we had used the concept of an infinitesimal parameter δx that raised some controversy. The status of this infinitesimal parameter is then elucidated in the framework of the CLT. Finally, we use (...) the formal apparatus developed in our previous papers and the results of the present one to advance an alternative objective interpretation of quantummechanics in which its relations with the classical framework are made explicit. The relations between our approach and those using the Wigner–Moyal transformation are also addressed. (shrink)
This paper argues that ontic structural realism (OSR) faces a dilemma: either it remains on the general level of realism with respect to the structure of a given theory, but then it is, like epistemic structural realism, only a partial realism; or it is a complete realism, but then it has to answer the question how the structure of a given theory is implemented, instantiated or realized and thus has to argue for a particular interpretation of the theory in question. (...) This claim is illustrated by examining how OSR fares with respect to the three main candidates for an ontology of quantummechanics, namely many worlds-type interpretations, collapse-type interpretations and hidden variable-type interpretations. The result is that OSR as such is not sufficient to answer the question of what the world is like if quantummechanics is correct. (shrink)
Several errors in Stapp's interpretation of quantummechanics and its application to mental causation (Henry P. Stapp, “Quantum theory and the role of mind in nature,” Foundations of Physics 31, 1465–1499 (2001)) are pointed out. An interpretation of (standard) quantummechanics that avoids these errors is presented.
It is argued that Robinson's attempt to show that alpha particle emission contradicts orthodox quantummechanics does not succeed. However, the possibility remains that alpha particle emission does contradict quantummechanics.
The validity of the conclusion to the nonlocality of quantummechanics, accepted widely today as the only reasonable solution to the EPR and Bell issues, is questioned and criticized. Arguments are presented which remove the compelling character of this conclusion and make clear that it is not the most obvious solution. Alternative solutions are developed which are free of the contradictions related with the nonlocality conclusion. Firstly, the dependence on the adopted interpretation is shown, with the conclusion that (...) the alleged nonlocality property of the quantum formalism may have been reached on the basis of an interpretation that is unnecessarily restrictive. Secondly, by extending the conventional quantum formalism along the lines of Ludwig and Davies it is shown that the Bell problem may be related to complementarity rather than to nonlocality. Finally, the dependence on counterfactual reasoning is critically examined. It appears that locality on the quantum level may still be retained provided one accepts a newly proposed principle of nonreproducibility at the individual quantum level as an alternative of quantum nonlocality. It is concluded that the locality principle can retain its general validity, in full conformity with all experimental data. (shrink)
I propose a new class of interpretations, real world interpretations, of the quantum theory of closed systems. These interpretations postulate a preferred factorization of Hilbert space and preferred projective measurements on one factor. They give a mathematical characterisation of the different possible worlds arising in an evolving closed quantum system, in which each possible world corresponds to a (generally mixed) evolving quantum state. In a realistic model, the states corresponding to different worlds should be (...) expected to tend towards orthogonality as different possible quasiclassical structures emerge or as measurement-like interactions produce different classical outcomes. However, as the worlds have a precise mathematical definition, real world interpretations need no definition of quasiclassicality, measurement, or other concepts whose imprecision is problematic in other interpretational approaches. It is natural to postulate that precisely one world is chosen randomly, using the natural probability distribution, as the world realised in Nature, and that this world’s mathematical characterisation is a complete description of reality. (shrink)
In a previous paper, a statistical method of constructing quantum models of classical properties has been described. The present paper concludes the description by turning to classical mechanics. The quantum states that maximize entropy for given averages and variances of coordinates and momenta are called ME packets. They generalize the Gaussian wave packets. A non-trivial extension of the partition-function method of probability calculus to quantummechanics is given. Non-commutativity of quantum variables limits its usefulness. (...) Still, the general form of the state operators of ME packets is obtained with its help. The diagonal representation of the operators is found. A general way of calculating averages that can replace the partition function method is described. Classical mechanics is reinterpreted as a statistical theory. Classical trajectories are replaced by classical ME packets. Quantum states approximate classical ones if the product of the coordinate and momentum variances is much larger than Planck constant. Thus, ME packets with large variances follow their classical counterparts better than Gaussian wave packets. (shrink)
Mereological nihilism is the philosophical position that there are no items that have parts. If there are no items with parts then the only items that exist are partless fundamental particles, such as the true atoms (also called philosophical atoms) theorized to exist by some ancient philosophers, some contemporary physicists, and some contemporary philosophers. With several novel arguments I show that mereological nihilism is the correct theory of reality. I will also discuss strong similarities that mereological nihilism has with empirical (...) results in quantum physics. And I will discuss how mereological nihilism vindicates a few other theories, such as a very specific theory of philosophical atomism, which I will call quantum abstract atomism. I will show that mereological nihilism also is an interpretation of quantummechanics that avoids the problems of other interpretations, such as the widely known, metaphysically generated, quantum paradoxes of quantum physics, which ironically are typically accepted as facts about reality. I will also show why it is very surprising that mereological nihilism is not a widely held theory, and not the premier theory in philosophy. (shrink)
Several philosophers of science have claimed that the conceptual difficulties of quantummechanics can be resolved by appealing to a particular interpretation of probability theory. For example, Popper bases his treatment of quantummechanics on the propensity interpretation of probability, and Margenau bases his treatment of quantummechanics on the frequency interpretation of probability. The purpose of this paper is (i) to consider and reject such claims, and (ii) to discuss the question of whether (...) the ψ -function refers to an individual system or to an ensemble of systems. (shrink)
The transactional interpretation of quantummechanics, following the time-symmetric formulation of electrodynamics, uses retarded and advanced solutions of the Schrödinger equation and its complex conjugate to understand quantum phenomena by means of transactions. A transaction occurs between an emitter and a specific absorber when the emitter has received advanced waves from all possible absorbers. Advanced causation always raises the specter of paradoxes, and it must be addressed carefully. In particular, different devices involving contingent absorbers or various types (...) of interaction-free measurements have been proposed as threatening the original version of the transactional interpretation. These proposals will be analyzed by examining in each case the configuration of absorbers and, in the special case of the so-called quantum liar experiment, by carefully following the development of retarded and advanced waves through the Mach-Zehnder interferometer. We will show that there is no need to resort to the hierarchy of transactions that some have proposed, and will argue that the transactional interpretation is consistent with the block-universe picture of time. (shrink)
In 1960–1962, E. Kähler enriched É. Cartan’s exterior calculus, making it suitable for quantummechanics (QM) and not only classical physics. His “Kähler-Dirac” (KD) equation reproduces the fine structure of the hydrogen atom. Its positron solutions correspond to the same sign of the energy as electrons.The Cartan-Kähler view of some basic concepts of differential geometry is presented, as it explains why the components of Kähler’s tensor-valued differential forms have three series of indices. We demonstrate the power of his (...) calculus by developing for the electron’s and positron’s large components their standard Hamiltonian beyond the Pauli approximation, but without resort to Foldy-Wouthuysen transformations or ad hoc alternatives (positrons are not identified with small components in K ähler’s work). The emergence of negative energies for positrons in the Dirac theory is interpreted from the perspective of the KD equation. Hamiltonians in closed form (i.e. exact through a finite number of terms) are obtained for both large and small components when the potential is time-independent.A new but as yet modest new interpretation of QM starts to emerge from that calculus’ peculiarities, which are present even when the input differential form in the Kähler equation is scalar-valued. Examples are the presence of an extra spin term, the greater number of components of “wave functions” and the non-association of small components with antiparticles. Contact with geometry is made through a Kähler type equation pertaining to Clifford-valued differential forms. (shrink)
At the philosophical foundations of our best and deepest theory of the structure of reality, namely quantummechanics, there is an intellectual scandal that reflects badly on most of this century’s leading physicists and philosophers of physics. One way of making the nature of the scandal plain is simply to observe that this paper  by Lockwood is untainted by it. Lockwood gives us an up to date investigation of metaphysics, and discusses the implications of quantum theory (...) for some of the bread and butter concepts of philosophy, such as reality, the self and causality. The scandal is that there is very little other work of that description in the literature, and what little there is, is systematically disregarded by mainstream thinking in both philosophy and physics. Despite the unrivalled empirical success of quantum theory, the very suggestion that it may be literally true as a description of nature is still greeted with cynicism, incomprehension and even anger. (shrink)
In this paper, possible objections to the propensity microrealistic version of quantummechanics proposed in Part I are answered. This version of quantummechanics is compared with the statistical, particle microrealistic viewpoint, and a crucial experiment is proposed designed to distinguish between these to microrealistic versions of quantummechanics.
We introduce a two-party communication complexity problem in which the probability of success by using a particular strategy allows the parties to detect with certainty whether or not some forbidden communication has taken place. We show that theprobability of success is bounded by nature; any conceivable method which gives a probability of success outside these bounds is impossible. Moreover, any conceivable method to solve the problem which gives a probability success within these bounds is possible in nature. This example suggests (...) that a suitaby chosen set of communication complexity problems could be the basis of an information-theoretic axiomatization of quantummechanics. (shrink)
Bohmian mechanics represents the universe as a set of paths with a probability measure defined on it. The way in which a mathematical model of this kind can explain the observed phenomena of the universe is examined in general. It is shown that the explanation does not make use of the full probability measure, but rather of a suitable set function deriving from it, which defines relative typicality between single-time cylinder sets. Such a set function can also be derived (...) directly from the standard quantum formalism, without the need of an underlying probability measure. The key concept for this derivation is the quantum typicality rule, which can be considered as a generalization of the Born rule. The result is a new formulation of quantummechanics, in which particles follow definite trajectories, but which is based only on the standard formalism of quantummechanics. (shrink)
If quantummechanics is correct and there is a finite upper bound for the speed of causal influences (e.g., the speed of light), then quantummechanics is complete (i.e., it does not admit a more detailed description in terms of hidden variables). Here I show that the conclusion holds if we replace the assumption of bounded velocity by the assumption that there is a finite upper bound to the memory a finite physical system can store (e.g., (...) the Holevo bound). On the way to this conclusion I first show that, although the quantum violation of an inequality valid for any non-contextual model can be explained with a classical contextual model, the inequality can be promoted to a Bell inequality in which, if the model is contextual, then it must be also non-local. This suggests that there is something non-classical in any contextual explanation of the individual systems, and leads us to the question of which are the minimum resources (and specifically memory) any contextual explanation should consume. (shrink)
The present paper reveals (non-relativistic) quantummechanics as an emergent property of otherwise classical ergodic systems embedded in a stochastic vacuum or zero-point radiation field (zpf). This result provides a theoretical basis for understanding recent numerical experiments in which a statistical analysis of an atomic electron interacting with the zpf furnishes the quantum distribution for the ground state of the H atom. The action of the zpf on matter is essential within the present approach, but it is (...) the ergodic demand what ultimately leads to the matrix formulation of quantummechanics. The paper thus represents a step forward in the quest for an elucidation of the fundamentals of quantummechanics. (shrink)
After a quick historical account of the introduction of the group-theoretical description of quantummechanics in terms of symmetries, as proposed by Weyl, we examine some unpublished papers by Ettore Majorana. Remarkable results achieved by him in frontier research topics as well as in physics teaching point out that the Italian physicist can be well considered as a follower of Weyl in his reformulation of quantummechanics.
Pekka Lahti is a prominent exponent of the renaissance of foundational studies in quantummechanics that has taken place during the last few decades. Among other things, he and coworkers have drawn renewed attention to, and have analyzed with fresh mathematical rigor, the threat of inconsistency at the basis of quantum theory: ordinary measurement interactions, described within the mathematical formalism by Schrödinger-type equations of motion, seem to be unable to lead to the occurrence of definite measurement outcomes, (...) whereas the same formalism is interpreted in terms of probabilities of precisely such definite outcomes. Of course, it is essential here to be explicit about how definite measurement results (or definite properties in general) should be represented in the formalism. To this end Lahti et al. have introduced their objectification requirement that says that a system can be taken to possess a definite property if it is certain (in the sense of probability 1) that this property will be found upon measurement. As they have gone on to demonstrate, this requirement entails that in general definite outcomes cannot arise in unitary measuring processes.In this paper we investigate whether it is possible to escape from this deadlock. As we shall argue, there is a way out in which the objectification requirement is fully maintained. The key idea is to adapt the notion of objectivity itself, by introducing relational or perspectival properties. It seems that such a “relational perspective” offers prospects of overcoming some of the long-standing problems in the interpretation of quantummechanics. (shrink)
E. Schrödinger's ideas on interpreting quantummechanics have been recently re-examined by historians and revived by philosophers of quantummechanics. Such recent re-evaluations have focused on Schrödinger's retention of space–time continuity and his relinquishment of the corpuscularian understanding of microphysical systems. Several of these historical re-examinations claim that Schrödinger refrained from pursuing his 1926 wave-mechanical interpretation of quantummechanics under pressure from the Copenhagen and Göttingen physicists, who misinterpreted his ideas in their dogmatic pursuit (...) of the complementarity doctrine and the principle of uncertainty. My analysis points to very different reasons for Schrödinger's decision and, accordingly, to a rather different understanding of the dialogue between Schrödinger and N. Bohr, who refuted Schrödinger's arguments. Bohr's critique of Schrödinger's arguments predominantly focused on the results of experiments on the scattering of electrons performed by Bothe and Geiger, and by Compton and Simon. Although he shared Schrödinger's rejection of full-blown classical entities, Bohr argued that these results demonstrated the corpuscular nature of atomic interactions. I argue that it was Schrödinger's agreement with Bohr's critique, not the dogmatic pressure, which led him to give up pursuing his interpretation for 7 yr. Bohr's critique reflected his deep understanding of Schrödinger's ideas and motivated, at least in part, his own pursuit of his complementarity principle. However, in 1935 Schrödinger revived and reformulated the wave-mechanical interpretation. The revival reflected N. F. Mott's novel wave-mechanical treatment of particle-like properties. R. Shankland's experiment, which demonstrated an apparent conflict with the results of Bothe–Geiger and Compton–Simon, may have been additional motivation for the revival. Subsequent measurements have proven the original experimental results accurate, and I argue that Schrödinger may have perceived even the reformulated wave-mechanical approach as too tenuous in light of Bohr's critique. (shrink)
A new ensemble interpretation of quantummechanics is proposed according to which the ensemble associated to a quantum state really exists: it is the ensemble of all the systems in the same quantum state in the universe. Individual systems within the ensemble have microscopic states, described by beables. The probabilities of quantum theory turn out to be just ordinary relative frequencies probabilities in these ensembles. Laws for the evolution of the beables of individual systems are (...) given such that their ensemble relative frequencies evolve in a way that reproduces the predictions of quantummechanics.These laws are highly non-local and involve a new kind of interaction between the members of an ensemble that define a quantum state. These include a stochastic process by which individual systems copy the beables of other systems in the ensembles of which they are a member. The probabilities for these copy processes do not depend on where the systems are in space, but do depend on the distribution of beables in the ensemble.Macroscopic systems then are distinguished by being large and complex enough that they have no copies in the universe. They then cannot evolve by the copy law, and hence do not evolve stochastically according to quantum dynamics. This implies novel departures from quantummechanics for systems in quantum states that can be expected to have few copies in the universe. At the same time, we are able to argue that the center of masses of large macroscopic systems do satisfy Newton’s laws. (shrink)
The Conditional Probability Interpretation of QuantumMechanics replaces the abstract notion of time used in standard QuantumMechanics by the time that can be read off from a physical clock. The use of physical clocks leads to apparent non-unitary and decoherence. Here we show that a close approximation to standard QuantumMechanics can be recovered from conditional QuantumMechanics for semi-classical clocks, and we use these clocks to compute the minimum decoherence predicted (...) by the Conditional Probability Interpretation. (shrink)
An SR model is presented that shows how an objective (noncontextual and local) interpretation of quantummechanics can be constructed, which contradicts some well-established beliefs following from the standard interpretation of the theory and from known no-go theorems. The SR model is not a hidden variables theory in the standard sense, but it can be considered a hidden parameters theory which satisfies constraints that are weaker than those usually imposed on standard hidden variables theories. The SR model is (...) also extended in a natural way that shows how a broader theory embodying quantummechanics can be envisaged which is realistic in a semantic sense, hence compatible with various “realistic” perspectives. (shrink)