scholarly journals Contiguity and the Quantum Theory of Measurement

1995 ◽  
Vol 48 (4) ◽  
pp. 613 ◽  
Author(s):  
HS Green
Keyword(s):  
Information Theory ◽  
Quantum Mechanics ◽  
Theory Of Measurement ◽  
Hidden Variables ◽  
Conserved Quantities ◽  
Epr Paradox ◽  
Measuring Devices ◽  
Interpretations Of Quantum Mechanics ◽  
Utility Of Information ◽  
Quantum Theory Of Measurement

This paper presents a comprehensive treatement of the problem of measurement in microscopic physics, consistent with the indeterministic Copenhagen interpretation of quantum mechanics and information theory. It is pointed out that there are serious difficulties in reconciling the deterministic interpretations of quantum mechanics, based on the concepts of a universal wave function or hidden variables, with the principle of contiguity. Quantum mechanics is reformulated entirely in terms of observables, represented by matrices, including the statistical matrix, and the utility of information theory is illustrated by a discussion of the EPR paradox. The principle of contiguity is satisfied by all conserved quantities. A theory of the operation of macroscopic measuring devices is given in the interaction repesentation, and the attenuation of the indeterminacy of a microscopic observable in the process of measurement is related to observable changes of entropy.

PROBING BELL'S INEQUALITY WITH CLASSICAL SYSTEMS

2010 ◽  
Vol 09 (04) ◽  
pp. 395-402 ◽  
Author(s):  
D. K. FERRY
Keyword(s):  
Quantum Mechanics ◽  
Bell Inequality ◽  
Hidden Variables ◽  
Optical Polarization ◽  
Bell’S Inequality ◽  
Epr Paradox ◽  
Quantum Theories ◽  
Considerable Evidence ◽  
Classical Systems ◽  
Quantum Behavior

From the early days of quantum mechanics, there has been a discussion on the concept of reality, exemplified by the EPR paradox. To many, the idea of the paradox and the possibility of local hidden variables was dismissed by the Bell inequality. Yet, there remains considerable evidence that this inequality can be violated even by classical systems, so that experiments showing quantum behavior and the violation of the inequality must be questioned. Here, we demonstrate that classical optical polarization experiments can be shown to violate the Bell inequality. Hence, such experiments cannot be used to distinguish between classical and quantum theories.

MATHEMATICAL ASPECTS OF QUANTUM PHASE

1995 ◽  
Vol 09 (20) ◽  
pp. 2597-2687 ◽  
Author(s):  
D.A. DUBIN ◽  
M.A. HENNINGS ◽  
T.B. SMITH
Keyword(s):  
Quantum Mechanics ◽  
Quantum Theory ◽  
Function Theory ◽  
Theory Of Measurement ◽  
Quantum Phase ◽  
Phase Operator ◽  
Current State ◽  
Classical Function ◽  
Quantum Theory Of Measurement

We consider the current state of the quest for a quantum phase operator, which started in the earliest days of quantum mechanics.4–7 Particular emphasis has been placed on analysis of the structure of the several distinct theories, both physical and mathematical, which has led us from classical function theory to the quantum theory of measurement.

Über das Einstein-Podolsky-Rosen Paradoxon / On the Einstein-Podolsky-Rosen Paradox

1974 ◽  
Vol 29 (4) ◽  
pp. 539-548 ◽  
Author(s):  
P. Mittelstaedt
Keyword(s):  
Quantum Mechanics ◽  
Quantum Theory ◽  
Hidden Variables ◽  
Physical Reality ◽  
Experimental Investigations ◽  
Epr Paradox ◽  
Realistic Interpretation ◽  
Epr Experiment ◽  
Einstein Podolsky Rosen ◽  
Ordinary Quantum

The EPR experiment is analysed in terms of ordinary quantum mechanics and shown to be compatible with the orthodox interpretation of this theory. There is no need to refer to Bohrs resolution of the EPR paradox, nor is it necessary to assume any further unusual properties of the quantum physical reality. In particular, it is shown that the EPR experiment does not contradict the fact that incommensurable properties cannot be objectivized simultaneously in a quantum mechanical system, and that the measuring process can be understood in terms of quantum theory as an interaction of the measuring apparatus and the object system. From these results it follows that there is no reason to search for modifications of the quantum theory which might be more convenient for a realistic interpretation of the EPR experiment. Furthermore, the EPR experiment cannot be used as a motivation for introducing hidden variables into the quantum theory. Experimental investigations which try to test quantum mechanics in respect to the possibility of introducing local hidden variables can therefore not be justified by the EPR paradox.

scholarly journals Quantum mechanics teaching resources from the Institute of Physics

2014 ◽  
pp. 40-43
Author(s):  
Antje Kohnle ◽  
Derek Raine
Keyword(s):  
Quantum Mechanics ◽  
Quantum Information ◽  
Teaching And Learning ◽  
Hidden Variables ◽  
Mathematical Structure ◽  
Teaching Resources ◽  
Creative Commons ◽  
Introductory Course ◽  
Interpretations Of Quantum Mechanics ◽  
Two Level Systems

In December 2013, the Institute of Physics (IOP) launched a set of freely available resources at quantumphysics.iop.org for the teaching and learning of quantum mechanics. The website includes about 80 short articles written by experts in the field and 17 interactive simulations with accompanying activities for an introductory course in quantum mechanics starting from two-level systems. The articles are arranged according to five themes, including a focus on quantum information, interpretations of quantum mechanics, the mathematical structure of the theory, physics applications and historical experiments. The resources make topics such as entanglement, hidden variables and quantum information theory accessible to introductory-level students. They can be used flexibly for a variety of instructional aims at both the introductory and more advanced level. The website includes links to pre-readings, suggestions for further reading, a glossary of technical terms and allows users to rate their understanding of articles.Sharing of these resources is encouraged, with all usage under the Creative Commons CC BY-NC-ND licence. Solutions to problems and activities are available for instructors by emailing [email protected]. Instructors interested in evaluating these resources with their students in order to help us further develop and optimize the site are requested to contact the corresponding author.

Schrödinger’s Cat and the Meaning of It All

2017 ◽  
Author(s):  
Frank S. Levin
Keyword(s):  
Quantum Mechanics ◽  
Measuring Instruments ◽  
Measuring Devices ◽  
Interpretations Of Quantum Mechanics ◽  
Schrödinger Cat ◽  
Schrodinger Cat State

Chapter 15 deals with various unresolved issues, such as how measurements are to be described, whether they induce collapse of linear superpositions, and if so, what the result should be. Another is whether quantum mechanics applies to macroscopic measuring devices, and if not, why not. Some of these issues are addressed via the Schrödinger cat-in-the-box experiment, in particular whether the cat is ever half alive and half dead; analogs of the corresponding Schrödinger-cat state (not involving a cat) have been studied experimentally. For Schrödinger, it was ridiculous to apply quantum mechanics to macroscopic situations, nevertheless, it has been explored by many physicists. Whether measurements induce collapse and whether collapse arises in various formulations/interpretations of quantum mechanics is examined in the context of generic measuring instruments known as pointer devices. Various conclusions have been reached, though consensus has not, despite only one interpretation having been verified experimentally.

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