Different Interpretations Of Quantum Mechanics Research Articles

Tabletop Experiments for Quantum Gravity Are Also Tests of the Interpretation of Quantum Mechanics

Recently there has been a great deal of interest in tabletop experiments intended to exhibit the quantum nature of gravity by demonstrating that it can induce entanglement. We argue that these experiments also provide new information about the interpretation of quantum mechanics: under appropriate assumptions, $\psi$-complete interpretations will generally predict that these experiments will have a positive result, $\psi$-nonphysical interpretations predict that these experiments will not have a positive result, and for $\psi$-supplemented models there may be arguments for either outcome. We suggest that a positive outcome to these experimenst would rule out a class of quantum gravity models that we refer to as $\psi$-incomplete quantum gravity (PIQG) - i.e. models of the interaction between quantum mechanics and gravity in which gravity is coupled to non-quantum beables rather than quantum beables. We review some existing PIQG models and consider what more needs to be done to make these sorts of approaches more appealing, and finally we discuss a cosmological phenomenon which could be regarded as providing evidence for PIQG models.

On the status of quantum tunnelling time

How long does a quantum particle take to traverse a classically forbidden energy barrier? In other words, what is the correct expression for quantum tunnelling time? This seemingly simple question has inspired widespread debate in the physics literature. I argue that we should not expect the orthodox interpretation of quantum mechanics to provide a unique correct expression for quantum tunnelling time, because to do so it would have to provide a unique correct answer to a question whose assumptions are in tension with its core interpretational commitments. I explain how this conclusion connects to time’s special status in quantum mechanics, the meaningfulness of classically inspired concepts in different interpretations of quantum mechanics, the prospect of constructing experimental tests to distinguish between different interpretations, and the status of weak measurement in resolving questions about the histories of subensembles.

How Different Interpretations of Quantum Mechanics can Enrich Each Other: The Case of the Relational Quantum Mechanics and the Modal-Hamiltonian Interpretation

How Different Interpretations of Quantum Mechanics can Enrich Each Other: The Case of the Relational Quantum Mechanics and the Modal-Hamiltonian Interpretation

Foundations of Quantum Mechanics

Quantum mechanics is a mathematical formalism that models the dynamics of physical objects. It deals with the elementary constituents of matter (atoms, subatomic and elementary particles) and of radiation. It is very accurate in predicting observable physical phenomena, but has many puzzling properties. The foundations of quantum mechanics are a domain in which physics and philosophy concur in attempting to find a fundamental physical theory that explains the puzzling features of quantum mechanics, while remaining consistent with its mathematical formalism. Several theories have been proposed for different interpretations of quantum mechanics. However, there is no consensus regarding any of these theories.

The Role of the Exalted Mind in the Observer Observed Quantum Reality

The great advances in science precipitated by the advent of quantum mechanics in the 20th century have profound implications for the nature of reality. The universe is now assumed to be fundamentally quantum at all scales of existence. As such, ancient questions about what the roles of human beings in the universe are, what is the relationship between the observer and the observed, the role of the mind, existence itself and the nature of experiences, can now also be approached in new scientific ways. This provides the opportunity to explore mathematical formalisms that relate to relationships between the observer and the observed, through three principles or universal laws which apply at all levels of existence. These principles form the essence of a vast ocean of qualia of experience. Such approaches that we advocate here provide a formalism that goes beyond specific interpretations of quantum mechanics and have strong philosophical foundations in both Western philosophy as well as the monistic contemplative systems of the East. We present a plausible thesis that what is the unifying principle of all existence is universal Consciousness, which when turned within is pure Awareness of Being. The mind and the countless experiences of qualia in this inner vision encompass ancient eternal views of contemplation where the observer, the observer and the process of unifying them form an undivided wholeness. The exalted ancient yet modern view would resonate with both the non-dual ancient teachings as well as different interpretations of quantum mechanics wherein the observed system and the observing subject are inexorably tied together in an undivided Wholeness of Being. The role of the mind is critical and we use the term Exalted Mind to distinguish higher functions from ordinary mind. The implications for humanity are indeed profound, in our view form the foundation of the emerging scientific and medical paradigms, the dawn of a new era of conscious non-dual, science-based Awareness.

Electron Charge Density: A Clue from Quantum Chemistry for Quantum Foundations

Within quantum chemistry, the electron clouds that surround nuclei in atoms and molecules are sometimes treated as clouds of probability and sometimes as clouds of charge. These two roles, tracing back to Schr\"odinger and Born, are in tension with one another but are not incompatible. Schr\"odinger's idea that the nucleus of an atom is surrounded by a spread-out electron charge density is supported by a variety of evidence from quantum chemistry, including two methods that are used to determine atomic and molecular structure: the Hartree-Fock method and density functional theory. Taking this evidence as a clue to the foundations of quantum physics, Schr\"odinger's electron charge density can be incorporated into many different interpretations of quantum mechanics (and extensions of such interpretations to quantum field theory).

On the Classification Between psi-Ontic and psi-Epistemic Ontological Models

Harrigan and Spekkens (Found Phys 40:125–157, 2010) provided a categorization of quantum ontological models classifying them as psi-ontic or psi-epistemic if the quantum state psi describes respectively either a physical reality or mere observers’ knowledge. Moreover, they claimed that Einstein—who was a supporter of the statistical interpretation of quantum mechanics—endorsed an epistemic view of psi . In this essay we critically assess such a classification and some of its consequences by proposing a twofold argumentation. Firstly, we show that Harrigan and Spekkens’ categorization implicitly assumes that a complete description of a quantum system (its ontic state, lambda) only concerns single, individual systems instantiating absolute, intrinsic properties. Secondly, we argue that such assumptions conflict with some current interpretations of quantum mechanics, which employ different ontic states as a complete description of quantum systems. In particular, we will show that, since in the statistical interpretation ontic states describe ensembles rather than individuals, such a view cannot be considered psi-epistemic. As a consequence, the authors misinterpreted Einstein’s view concerning the nature of the quantum state. Next, we will focus on relational quantum mechanics and perspectival quantum mechanics, which in virtue of their relational and perspectival metaphysics employ ontic states lambda dealing with relational properties. We conclude that Harrigan and Spekkens’ categorization is too narrow and entails an inadequate classification of the mentioned interpretations of quantum theory. Hence, any satisfactory classification of quantum ontological models ought to take into account the variations of lambda across different interpretations of quantum mechanics.

Charting the landscape of interpretation, theory rivalry, and underdetermination in quantum mechanics

When we speak about different interpretations of quantum mechanics it is suggested that there is one single quantum theory that can be interpreted in different ways. However, after an explicit characterization of what it is to interpret quantum mechanics, the right diagnosis is that we have a case of predictively equivalent rival theories. I extract some lessons regarding the resulting underdetermination of theory choice. Issues about theoretical identity, theoretical and methodological pluralism, and the prospects for a realist stance towards quantum theory can be properly addressed once we recognize that interpretations of quantum mechanics are rival theories.

Genesis of Karl Popper's EPR-like experiment and its resonance amongst the physics community in the 1980s

I present the reconstruction of the involvement of Karl Popper in the community of physicists concerned with foundations of quantum mechanics, in the 1980s. At that time Popper gave active contribution to the research in physics, of which the most significant is a new version of the EPR thought experiment, alleged to test different interpretations of quantum mechanics. The genesis of such an experiment is reconstructed in detail, and an unpublished letter by Popper is reproduced in the present paper to show that he formulated his thought experiment already two years before its first publication in 1982. The debate stimulated by the proposed experiment as well as Popper's role in the physics community throughout 1980s is here analysed in detail by means of personal correspondence and publications.

Ciência e Ideologia. O caso da Física

The thoughts of Magalhães-Vilhena concerning the relation between science and ideology are a contribution to enlighten the philosophical implications of the groundings of science, something that was under the interested look of the portuguese philosopher. It is having in mind the double meaning of science as productive force and as “manifestation of society’s spiritual life” that Magalhães-Vilhena guides his investigations in which he reveals the intimate relation between science, tecnique and social structures. For the author, it is necessary to perform that “criticism of principle” that reveals the positioning of each ideological tendency. Nowadays, quantum mechanics still rises a number of philosophical problems. Paying tribute to Vilhena’s work, I try to show the necessity of thinking in which way the different interpretations of quantum mechanics bear, in the roots of their oppositions, that most fundamental confrontation between materialism and idealism. I therefore pretend to show the pertinence and topicality of such “criticism of principle”.

Cambiando el pasado: ventajas de la retrocausación

Desde sus orígenes, la mecánica cuántica nos ha enfrentado a una serie de “misterios” que se desprenden de ella si es que consideramos esta teoría científica desde una perspectiva realista. En los primeros años del desarrollo de la teoría, científicos de la talla de Albert Einstein notaron las consecuencias de aceptar una teoría como esta, la que permitiría fenómenos como la no-localidad. Esto llevó a una parte de la comunidad científica a considerar que la mecánica cuántica era una teoría incompleta, pues debían existir variables que pudieran explicar los fenómenos “perturbadores” tales como la correlación entre partículas acopladas.Se han propuesto diferentes interpretaciones de la mecánica cuántica que han intentado develar o explicar la realidad subyacente a su formalismo. Una de estas interpretaciones es la llamada “Interpretación Transaccional” de la mecánica cuántica, defendida principalmente por el físico John G. Cramer. Según esta interpretación, los eventos cuánticos se entienden como interacciones causales entre ondas retrasadas viajando hacia adelante en el tiempo y ondas avanzadas viajando hacia atrás en el tiempo. Esta interpretación abre la puerta para aceptar un modelo de causación hacia el pasado o retrocausación.Autores como Phil Dowe o Huw Price han mostrado una postura favorable a un modelo de retrocausación por la capacidad de resolver efectivamente algunas de las características más perturbadoras derivadas de la mecánica cuántica. A pesar de que el costo intuitivo es bastante alto, la retrocausación es una de las interpretaciones posibles de los resultados de la correlación entre partículas acopladas que nos provee un marco explicativo con algunas ventajas interesantes.En este trabajo exploramos tales ventajas pues la retrocausación nos otorga un modelo explicativo generalizable para todos los casos de este tipo y presupone procesos y entidades que no quedan solamente en el campo especulativo sino que permitirían ciertas posibilidades de testeo. Rescataremos también la importancia de modelos explicativos no predictivos como ha sido el caso en otros campos de las ciencias naturales, siempre que no resulten ad hoc gracias a las restricciones que impiden su aplicación a cualquier caso.

Nonlocality and the Aharonov-Bohm Effect

At first sight the Aharonov-Bohm effect appears nonlocal, though not in the way EPR/ Bell correlations are generally acknowledged to be nonlocal. This paper applies an analysis of nonlocality to the Aharonov-Bohm effect to show that its peculiarities may be blamed either on a failure of a principle of local action or on a failure of a principle of separability. Different interpretations of quantum mechanics disagree on how blame should be allocated. The parallel between the Aharonov-Bohm effect and violations of Bell inequalities turns out to be so close that a balanced assessment of the nature and significance of quantum nonlocality requires a detailed study of both effects.

Quantum measurements and macrophysical reality: Epistemological implications of a proposed paradox

After an outline of the macrorealistic solutions to the difficulties of the measurement theory, a new paradox is proposed and then discussed in the light of three different interpretations of quantum mechanics.

Retrodiction in quantum mechanics, preferred Lorentz frames, and nonlocal measurements

We examine, in the context of the Einstein-Podolsky-Rosen-Bohm gedankenexperiment, problems associated with state reduction and with nonlocal influences according to different interpretations of quantum mechanics, when attempts are made to apply these interpretations in the relativistic domain. We begin by considering the significance of retrodiction within four different interpretations of quantum mechanics, and show that three of these interpretations, if applied in a relativistic context, can lead to ambiguities in their description of a process. We consider ways of dealing with these ambiguities, in particular focussing on the “preferred frame” hypothesis. We then re-examine an argument involving nonlocal measurements which claimed that the preferred frame hypothesis is not tenable, and show that this argument does not in fact necessitate a rejection of the preferred frame. We then suggest that, to avoid confusion, the preferred frame could be extended to cover unitary interactions as well as state reductions. We conclude with a brief examination of a proposal that state reduction should take effect across the backward light cone of a measurement event.

Double-slit experiment, copenhagen, neo-copenhagen and stochastic interpretation of quantum mechanics

Three different interpretations of quantum mechanics are applied in a new proposed version of the double-slit experiment. This new version shows that the orthodox Copenhagen interpretation of quantum mechanics does not agree, in this particular case, with the mathematical predictions of the formalism utilized in quantum mechanics.

Discussion of a proof, given by selleri and tarozzi, of the nonlocality of quantum mechanics

Three different interpretations of quantum mechanics are investigated in order to see whether a claim by Selleri and Tarozzi, to the effect that quantum mechanics is observably nonlocal, can be substantiated. It is demonstrated that none of these interpretations does support the claim.

In defence of Copenhagenism

We rebut the objections to the Copenhagen interpretation of quantum mechanics presented by Park [9,10], Margenau [10], and Popper [11]. It seems to us that these authors, having adopted different interpretations of quantum mechanics, have been unable to grasp the perspective of the Copenhagenist. They therefore miss the points which the Copenhagenist is making when he: (a) accords a special status to observations in quantum theory; (b) attributes a state vector to an individual system; (c) places restrictions on the simultaneous measurability of non-commuting observables; (d) hesitates to use his measurements for retrodictions. In our opinion, the arguments of the above authors reflect their incomprehension of Copenhagenism. Elsewhere [5,6] we have discussed two alternative interpretations of quantum mechanics which we have called Copenhagenism and Popperism. We have there shown how the dispute between the schools stems from disparate uses of the word ‘state’. We continue the discussion here within the context of the above points and show how these disparate notions of state are related to diverse notions of ‘behaviour’.

Interpretation of Quantum Mechanics and the Future of Physics

This paper deals with the problem of the interpretation of quantum mechanics, the nature of physical theory, and the future of physics. First, the question of why there are so many different interpretations of quantum mechanics proposed and accepted by outstanding quantum experts is treated. This requires a discussion of the relation between physics and philosophy and drawing a distinction between a physical formalism and a physical explanation. The Copenhagen interpretation is considered, criticized, and found to be unsatisfactory in some respects. Finally, an interpretation that contains ideas from previous interpretations but which may itself be new, is proposed. Hopefully, this is superior to the previous interpretations. It has, I believe, the advantage of logical clarity. In the process of doing this, I introduce a theory of levels of physical theory, according to which microscopic physical theory, as it develops in successive stages, becomes more and more adaptable to explaining—or at least taking cognizance of—fundamental biological or ultimately psychological phenomena.

The Weight of Simplicity in the Construction and Assaying of Scientific Theories

One of the most difficult and interesting problems of rational decision is the choice among possible diverging paths in theory construction and among competing scientific theories—i.e., systems of accurate testable hypotheses. This task involves many beliefs—some warranted and others not as warranted—and marks decisive crossroads. Suffice to recall the current conflict between the general theory of relativity and alternative theories of gravitation (e.g., Whitehead's) that account for the same empirical evidence, the rivalry among different interpretations of quantum mechanics (e.g., Bohr-Heisenberg's, de Broglie-Bohm's, and Landé's), and the variety of cosmological theories (e.g., Tolman's cyclical model and the steady-state theory). They all account for the same observed facts although they may predict different kinds of as yet unknown facts; they are consequently, up to now, empirically equivalent theories even though they are conceptually different and may even involve different philosophical views—i.e., they are conceptually inequivalent.