scholarly journals CORRELATIONS IN ENTANGLED STATES

2006 ◽  
Vol 20 (11n13) ◽  
pp. 1496-1503
Author(s):  
B. C. SANCTUARY
Keyword(s):  
Quantum Mechanics ◽  
Singlet State ◽  
Entangled States ◽  
Quantum Mechanical ◽  
Interpretation Of Quantum Mechanics ◽  
Hidden Variable ◽  
Phase Decoherence ◽  
Classical Correlations ◽  
Spin Pairs ◽  
Ensemble Interpretation

Entangled EPR spin pairs can be treated using the statistical ensemble interpretation of quantum mechanics. As such the singlet state results from an ensemble of spin pairs each with its own specific axis of quantization. This axis acts like a quantum mechanical hidden variable. If the spins lose coherence they disentangle into a mixed state that contains classical correlations. In this paper an infinitesimal phase decoherence is introduced to the singlet state in order to reveal more clearly some of the correlations. It is shown that a singlet state has no classical correlations.

Quantum Interference

2019 ◽  
pp. 66-88
Author(s):  
Jeffrey A. Barrett
Keyword(s):  
Hilbert Space ◽  
Wave Function ◽  
Quantum Mechanics ◽  
Quantum Interference ◽  
Standard Theory ◽  
Quantum Decoherence ◽  
Entangled States ◽  
Quantum Mechanical ◽  
Standard Formulation ◽  
Complex Valued

Moving to more subtle experiments, we consider how the standard formulation of quantum mechanics predicts and explains interference phenomena. Tracking the conditions under which one observes interference phenomena leads to the notion of quantum decoherence. We see why one must sharply distinguish between collapse phenomena and decoherence phenomena on the standard formulation of quantum mechanics. While collapses explain determinate measurement records, environmental decoherence just produces more complex, entangled states where the physical systems involved lack ordinary physical properties. We characterize the quantum-mechanical wave function as both an element of a Hilbert space and a complex-valued function over a configuration space. We also discuss how the wave function is interpreted in the standard theory.

scholarly journals PROLIFERATION OF OBSERVABLES AND MEASUREMENT IN QUANTUM-CLASSICAL HYBRIDS

2012 ◽  
Vol 10 (08) ◽  
pp. 1241012 ◽  
Author(s):  
HANS-THOMAS ELZE
Keyword(s):  
Quantum Mechanics ◽  
Free Will ◽  
Degrees Of Freedom ◽  
Cartesian Product ◽  
Entangled States ◽  
Quantum Mechanical ◽  
Analytical Mechanics ◽  
Hybrid Dynamics

Following a review of quantum-classical hybrid dynamics, we discuss the ensuing proliferation of observables and relate it to measurements of (would-be) quantum mechanical degrees of freedom performed by (would-be) classical ones (if they were separable). Hybrids consist in coupled classical (CL) and quantum mechanical (QM) objects. Numerous consistency requirements for their description have been discussed and are fulfilled here. We summarize a representation of quantum mechanics in terms of classical analytical mechanics which is naturally extended to QM–CL hybrids. This framework allows for superposition, separable, and entangled states originating in the QM sector, admits experimenter's "Free Will", and is local and nonsignaling. Presently, we study the set of hybrid observables, which is larger than the Cartesian product of QM and CL observables of its components; yet it is smaller than a corresponding product of all-classical observables. Thus, quantumness and classicality infect each other.

Constructing deterministic models for quantum mechanical systems

2020 ◽  
Vol 17 (supp01) ◽  
pp. 2040007
Author(s):  
Gerard ’t Hooft
Keyword(s):  
Quantum Mechanics ◽  
Essential Element ◽  
Quantum Mechanical ◽  
Interpretation Of Quantum Mechanics ◽  
Final States ◽  
Deterministic Models ◽  
Quantum Theories ◽  
Initial States ◽  
Quantum Mechanical Systems ◽  
Entire Theory

A sharper formulation is presented for an interpretation of quantum mechanics advocated by the author. We claim that only those quantum theories should be considered for which an ontological basis can be constructed. In terms of this basis, the entire theory can be considered as being deterministic. An example is illustrated: massless, noninteracting fermions are ontological. Subsequently, as an essential element of the deterministic interpretation, we put forward conservation laws concerning the ontological nature of a variable, and the uncertainties concerning the realization of states. Quantum mechanics can then be treated as a device that combines statistics with mechanical, deterministic laws, such that uncertainties are passed on from initial states to final states.

Faster-than-Light Schemes

Lightspeed ◽  
2019 ◽  
pp. 180-220
Author(s):  
John C. H. Spence
Keyword(s):  
Field Theory ◽  
Light Propagation ◽  
Measurement Problem ◽  
Natural Sciences ◽  
Entangled States ◽  
Interpretation Of Quantum Mechanics ◽  
Quantum Field ◽  
Speed Of Light ◽  
Many Body ◽  
Hidden Variable

Developments since Einstein are summarized. Our systems of units and their relationship to the speed of light. Light propagation in vacuum—what stuff is an electric field made of? Quantum field theory ideas. The Casimir force and energy. Olbers’ paradox and the cosmic horizon. Effect of gravity on speed of light. Schemes for messaging at speeds greater than that of light. The Einstein–Rosen–Podolsky paper of 1935 and its interpretation in simple terms. The reality of the quantum world. Hidden variable theories and Bell’s theorem. Interpretation of many-body quantum wavefunctions—Bohm, Born, Schrӧdinger, Heisenberg, de Broglie, their lives and contributions to physics. The Copenhagen interpretation of quantum mechanics and others. The measurement problem and collapse of the wavefunction. Entangled states. The unreasonable effectiveness of mathematics in the natural sciences.

6. Interpreting the quantum

2021 ◽  
pp. 110-132
Author(s):  
David Wallace
Keyword(s):  
Quantum Mechanics ◽  
Narrow Range ◽  
Scientific Practice ◽  
Experimental Results ◽  
Interpretation Of Quantum Mechanics ◽  
Correct Interpretation ◽  
Hidden Variable ◽  
Hidden Variable Theories ◽  
Scientific Results ◽  
Collapse Theories

This chapter surveys various proposals to interpret—that is, make sense of—quantum mechanics. We could attempt to think of quantum mechanics in purely instrumentalist terms, as an algorithm to predict observed experimental results. But this fits badly with scientific practice and is probably not viable. We could attempt to modify quantum mechanics itself to resolve the paradoxes, and there are some simple models that attempt to do that: some are ‘hidden-variable’ theories that add extra properties to the theory, some are ‘dynamical-collapse’ theories that modify the theory’s equations. But none of these models succeed in reproducing quantum theory’s predictions outside a relatively narrow range of applications. Or we could try to take the apparent indefiniteness of quantum mechanics literally, and interpret it as a theory of many parallel worlds. The correct interpretation of quantum mechanics remains controversial, but the search for understanding and interpretation of the theory has led to very substantial scientific results and is likely to lead to more.

scholarly journals Barad, Bohr, and quantum mechanics

Synthese ◽  
2021 ◽  
Author(s):  
Jan Faye ◽  
Rasmus Jaksland
Keyword(s):  
Social Sciences ◽  
Quantum Mechanics ◽  
Science Studies ◽  
Niels Bohr ◽  
Quantum Mechanical ◽  
Strict Sense ◽  
Interpretation Of Quantum Mechanics ◽  
Feminist Science ◽  
Interpretations Of Quantum Mechanics ◽  
Agential Realism

AbstractThe last decade has seen an increasing number of references to quantum mechanics in the humanities and social sciences. This development has in particular been driven by Karen Barad’s agential realism: a theoretical framework that, based on Niels Bohr’s interpretation of quantum mechanics, aims to inform social theorizing. In dealing with notions such as agency, power, and embodiment as well as the relation between the material and the discursive level, the influence of agential realism in fields such as feminist science studies and posthumanism has been profound. However, no one has hitherto paused to assess agential realism’s proclaimed quantum mechanical origin including its relation to the writings of Niels Bohr. This is the task taken up here. We find that many of the implications that agential realism allegedly derives from a Bohrian interpretation of quantum mechanics dissent from Bohr’s own views and are in conflict with those of other interpretations of quantum mechanics. Agential realism is at best consistent with quantum mechanics and consequently, it does not capture what quantum mechanics in any strict sense implies for social science or any other domain of inquiry. Agential realism may be interesting and thought provoking from the perspective of social theorizing, but it is neither sanctioned by quantum mechanics nor by Bohr’s authority. This conclusion not only holds for agential realism in particular, it also serves as a general warning against the other attempts to use quantum mechanics in social theorizing.

scholarly journals On quantum entanglement, counterfactuals, causality and dispositions

Synthese ◽  
2017 ◽  
Vol 197 (10) ◽  
pp. 4161-4185
Author(s):  
Tomasz Bigaj
Keyword(s):  
Quantum Mechanics ◽  
Entangled States ◽  
Causal Mechanism ◽  
Interpretation Of Quantum Mechanics ◽  
Counterfactual Conditionals ◽  
Local Character ◽  
Causal Connections ◽  
Local Correlations ◽  
Non Local ◽  
Counterfactual Approach

Abstract The existence of non-local correlations between outcomes of measurements in quantum entangled systems strongly suggests that we are dealing with some form of causation here. An assessment of this conjecture in the context of the collapse interpretation of quantum mechanics is the primary goal of this paper. Following the counterfactual approach to causation, I argue that the details of the underlying causal mechanism which could explain the non-local correlations in entangled states strongly depend on the adopted semantics for counterfactuals. Several relativistically-invariant interpretations of spatiotemporal counterfactual conditionals are discussed, and the corresponding causal stories describing interactions between parts of an entangled system are evaluated. It is observed that the most controversial feature of the postulated causal connections is not so much their non-local character as a peculiar type of circularity that affects them.

scholarly journals Quantum Mechanics and an Ontology of Intersubjectivity: Perils and Promises

Open Theology ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 325-341
Author(s):  
Marc A. Pugliese
Keyword(s):  
Quantum Mechanics ◽  
New Physics ◽  
Relativity Theory ◽  
Quantum Mechanical ◽  
Interpretation Of Quantum Mechanics ◽  
Experimental Procedure ◽  
Interpretations Of Quantum Mechanics ◽  
Ontological Categories ◽  
Per Se ◽  
The Many

AbstractContemporary theology has realized the importance of integrating what we know from the “new physics”-quantum mechanics and relativity theory-into the metaphysical and ontological categories used by theology to consider God, the world, and the God-world relationship. The categories of subjectivity and relationality have risen to prominence in these discussions. Both academic and popular presentations can obscure the vital distinction between what physicists agree on concerning quantum mechanics and the contested interpretation of quantum mechanics, or what quantum mechanics reveals about reality. After (1) summarizing the significant distinction between quantum mechanics per se and the interpretations of quantum mechanics and (2) the agreed upon quantum mechanical experimental procedure and its attendant mathematical formalism, as well as a few of the foremost interpretations, this paper (3) attempts a minimalist culling of some rudimentary but clear ontological principles and categories from what is agreed upon in quantum mechanics, without appeals-tacit or explicit-to one of the many controversial interpretations or to contestable philosophical assumptions and deductions, and these are: experience, subjectivity, relationship, and event. The paper closes by (4) commending one speculative scheme that is especially conducive to developing an interpretation of quantum mechanics consonant with the ontological principles and categories so derived, that of Alfred North Whitehead

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