arXiv subjects

Donald A. Graft

Publications and source records attributed to Donald A. Graft.

7 recordsLinked to original sources

arXiv2016

Anomalous Postselection in the Hensen et al. Bell Test

It is shown that the data of the Hensen et al. Bell test experiment exhibits anomalous postselection that can fully account for the apparent violation of the CHSH inequality. A simulation of a local realist model implementing similar postselection is presented. The model produces an apparent violation of CHSH indistinguishable from that of the experiment. The experimental data also appears to violate no-signaling, and it is shown how postselection can produce an artifactual violation of no-signaling. The Hensen et al. experiment does not succeed in rejecting classical locality and therefore does not confirm quantum nonlocality.

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arXiv2016

The Quantum Prediction for Einstein-Podolsky-Rosen (EPR) Experiments

Quantum mechanics allows for multiple predictions for the outcome of an EPR experiment. The correct calculation must be used, guided by the physical conditions of the experiment. The quantum joint prediction for EPR correlation is derived and shown to involve a single sampling. The solution for separated measurement, where there are two private samplings, is then developed using orthodox quantum mechanics with Luders' rule for state projection on measurement. The separated solution is shown to duplicate the predictions of the quantum joint solution. However, it is shown that this solution requires superluminal transmission of information and therefore it is physically impossible. Alternative predictions respecting special relativity are developed using both Von Neumann projection and null projection (no projection at all). Conditions for the proper application of state projection rules are considered and Luders' rule is identified as the primary culprit in the EPR paradox. It cannot be applied to EPR.

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arXiv2016

Clauser-Horne/Eberhard inequality violation by a local model

Thanks to its immunity to the detection loophole, the Clauser-Horne/Eberhard inequality plays an important role in tests of locality and in certification of quantum information protocols based on entanglement. I describe a local model that violates the inequality using a plausible mechanism relying upon a parameter of the apparatus, the source emission rate. The effect is generated through the analysis of time-tagged data using a standard windowed coincidence counting method. Significantly, the detection times here are not functions of the measurement settings, i.e., the fair coincidences assumption is satisfied. This finding has implications for the design and interpretation of experiments and for quantum information protocols, as it shows that the coincidence window mechanism cannot be eliminated by a demonstration of independence of the detection times and settings. The paper describes a reliable coincidence counting method and shows that it delivers an accurate count of true coincidences. Recent experimental tests of local realism based on the Clauser-Horne/Eberhard inequality are considered and it is shown that in one case (Christensen et al.) the emission rate is appropriately limited to ensure valid counting, and the data supports locality; in a second case (Giustina et al.) the experiment neglects to appropriately limit the emission rate, and the claimed violation can be accounted for locally.

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arXiv2015

Analysis of the Christensen et al. Clauser-Horne (CH)-Inequality-Based Test of Local Realism

The Clauser-Horne (CH) inequality can validly test aspects of locality when properly applied. This paper analyzes a recent CH-based EPRB experiment, the Christensen et al. experiment. Full details of the data analysis applied to the experiment are given. An alternative analysis is also presented that considers the role of accidental coincidences and confirms and justifies the main analysis. It is shown that the experiment confirms locality and disconfirms the quantum joint prediction. To make sense of this surprising finding, the conclusion presents a new rational interpretation of the EPR paradox. The paper also contributes to promulgation of robust and correct data analysis by describing the important degrees of freedom that affect the analysis, and that must be addressed in the analysis of any EPRB experiment.

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arXiv2014

On Bell-Like Inequalities for Testing Local Realism

Objections to the use of inequalities to address foundational issues are considered and shown to be invalid. The Clauser-Horne (CH) inequality is considered and interpreted in this light. It is shown that, applied correctly, the CH inequality can validly test aspects of locality. This paper establishes a firm methodological ground for a following paper analyzing a recent CH experiment.

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arXiv2013

On reconciling quantum mechanics and local realism

A necessary and natural change in our application of quantum mechanics to separated systems is shown to reconcile quantum mechanics and local realism. An analysis of separation and localization justifies the proposed change in application of quantum mechanics. An important EPRB experiment is reconsidered and it is seen that when it is correctly interpreted it supports local realism. This reconciliation of quantum mechanics with local realism allows the axiom sets of quantum mechanics, probability, and special relativity to be joined in a consistent global axiom set for physics.

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arXiv2013

A Local Realist Account of the Weihs et al EPRB Experiment

Quantum mechanics stands in conflict with local realism only in its treatment of separated systems. A modification of quantum mechanics that changes the handling of separated systems is suggested that can reconcile quantum mechanics with local realism. An apparent obstacle to this program is the experimental evidence, but I argue that the experiments have been misinterpreted. By way of example, I describe a local realistic account of one important EPRB experiment that is claimed to demonstrate nonlocal entanglement. The local model can be calibrated into both quantum and classical domains via adjustment of parameters of the apparatus. Weihs incorrectly dismisses these parameters as uncritical, whereas we show that device calibration is crucial. When properly interpreted, the experiments show that nonlocal entanglement is an error. The rest of quantum mechanics remains intact, and remains highly valued as a powerful probability calculus for observables. Quantum mechanics and local realism can be reconciled, and they each can offer useful paradigms for describing systems.

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