James T. Cushing

Quantum Paradoxes and Physical Reality

1 / Quantum Theorists and the Physical World.- 1.1. Three Central Questions about Physics.- 1.2. The Older Generation.- 1.3. The Middle Generation.- 1.4. The Younger Generation.- 1.5. Conclusions.- 2 / Is Quantum Mechanics a Complete Theory?.- 2.1. The Problem of Completeness and of Hidden Variables.- 2.2. De Broglies Paradox.- 2.3. The Spin-1/2 System in Quantum Mechanics.- 2.4. A Simple Proof of von Neumanns Theorem.- 2.5. The Theorem is not General Enough.- 2.6. Von Neumanns Theorem: Assumptions, Definitions, and Results.- 2.7. General Proof of von Neumanns Theorem.- 2.8. Jauch and Pirons Theorem.- 2.9. The Debate on Impossibility Proofs.- 3 / The Wave-Particle Duality.- 3.1. Duality for Photons.- 3.2. Duality for Neutrons.- 3.3. Einsteins Discovery of Duality.- 3.4. De Broglies Duality.- 3.5. Schrodingers Waves.- 3.6. Bohrs Complementarity.- 3.7. Focks Relativity with Respect to the Means of Observation.- 3.8. Heisenberg Beyond Complementarity.- 3.9. The Consciousness Interpretation.- 3.10. Delayed Choices.- 3.11. How to do what Complementarity Forbids.- 4 / Properties of Quantum Waves.- 4.1. Quantum Waves and Quantum Potential.- 4.2. Experiments on the Nature of Duality.- 4.3. Stimulated Emission.- 4.4. Quantitative Empty Wave Amplification.- 4.5. Two Further Experimental Proposals.- 4.6. Triple-Slit Experiments.- 4.7. The Bohm-Aharonov Effect.- 4.8. Further Ideas about Wave-Particle Duality.- 5 / The Einstein-Podolsky-Rosen Paradox.- 5.1. The Original Formulation.- 5.2. Bohrs Answer.- 5.3. Two Types of State Vectors.- 5.4. Spin States for Two Particles.- 5.5. Reality and Separability.- 5.6. The EPR Paradox: Quantum Mechanics Complete.- 5.7. The EPR Paradox: Quantum Mechanics not Complete.- 5.8. From Theory to Practice.- 5.9. The Experimental Information.- 5.10. Solution 1: Modifying the Past.- 5.11. Solution 2: Superluminal Connections.- 5.12. Solution 3: New Definitions of Probability.- 5.13. Solution 4: Modifications of Quantum Theory.- 6 / The EPR Paradox in the Real World.- 6.1. Criticisms of Einstein Locality.- 6.2. Probabilistic Einstein Locality.- 6.3. New Proof of Bells Inequality.- 6.4. Probabilities for Pairs of Correlated Systems.- 6.5. A New Factorizability Condition.- 6.6. All the Inequalities of Einstein Locality.- 6.7. Tests of the EPR Paradox in Particle Physics.- 6.8. On the Possibility of New Experiments.- 6.9. Variable Probabilities.- 7 / Perspectives of Physical Realism.- 7.1. Objectivity of Scientific Knowledge.- 7.2. Mathematics and Reality.- 7.3. The Role of History of Physics.- 7.4. Fragmentation of Modern Physics.- 7.5. Niels Bohr and Philosophy.- 7.6. Quantum Physics and Biological Sciences.- 7.7. Forms of Physical Realism.

Conceptual Foundations of Quantum Physical an Overview from Modern Perspectives

The Standard Interpretation and Beyond. The Quantum Measurement Paradox. Classical Limit of Quantum Mechanics. Quantum Nonlocality. Wave-Particle Duality of Light and Complementarity. Quantum Zeno Effect. Causality in Quantum Mechanics. Einsteins Critique of Quantum Mechanics: An Appraisal from Modern Perspectives. Index.

Quantum Theory and Explanatory Discourse: Endgame for Understanding?

Empirical adequacy, formal explanation and understanding are distinct goals of science. While no a priori criterion for understanding should be laid down, there may be inherent limitations on the way we are able to understand explanations of physical phenomena. I examine several recent contributions to the exercise of fashioning an explanatory discourse to mold the formal explanation provided by quantum mechanics to our modes of understanding. The question is whether we are capable of truly understanding (or comprehending) quantum phenomena, as opposed to simply accepting the formalism and certain irreducible quantum correlations. The central issue is that of understanding versus merely redefining terms to paper over our ignorance.

From Paradox to Reality: Our Basic Concepts of the Physical World

Preface Part I. At the Roof of the Endeavor: 1. Human limitations 2. Theory and the role of mathematics 3. Scientific objectivity 4. The aim of scientific theory Part II. The World of Relativity: 5. Space and time: from absolute to relative 6. Imposed consistency: special relativity 7. Gravitation as geometry: general relativity 8. Revolutions without revolutions Part III. The Quantum World: 9. The limits of the classical world 10. Concepts of the quantum world 11. From apparent paradox to a new reality 12. The present state of the art Epilogue Notes Glossary of technical terms Name index Subject index.

The spring‐mass system revisited

A vertically oscillating spring of mass m and spring constant k suspended from its upper end and with a mass M attached to its lower end is a system often used for demonstrations and experiments in introductory physics courses. We discuss the motion of this system for arbitrary values of e=m/M, 0≤e<∞ and show explicitly why theory predicts that the amplitude of the lowest normal‐mode frequency makes the major contribution to the motion of M (or of the lower end of the spring) for all values of e. Although a complete understanding of this fact involves detailed mathematical analysis, the results themselves are simply stated and readily verified even by students in an introductory calculus‐based physics course. The various predictions of the theory are easily demonstrated with simple equipment and lend themselves nicely to an introductory physics laboratory. These applications are discussed in some detail, and an analog electric circuit is given which exhibits similar behavior.

Electromagnetic mass, relativity, and the Kaufmann experiments

This paper presents the theoretical background for and the detailed analysis of Kaufmann’s 1901–1905 experiments to determine the e/m ratio for fast electrons. Far from providing the first experimental confirmation of Einstein’s special theory of relativity, as is often claimed in physics textbooks today, these data were initially interpreted as confirming Abraham’s classical model of a rigid spherical electron and as providing evidence against special relativity. Only in 1906–1907, upon Planck’s subsequent reanalysis of Kaufmann’s 1905 data, did these experiments become evidence marginally in favor of relativity over classical models of the electron. This particular issue, of the superiority of special realtivity over classical theory in providing a fit to e/m determinations, was not definitely settled until 1914 with new extensive and accurate data obtained by Neumann. The entire episode provides another example that science does not proceed by a strict falsificationist methodology. It shows rather that...

Vector Lorentz Transformations

A derivation of the vector Lorentz transformation is given by explicitly compounding the pure Lorentz transformation along one spatial axis with pure spatial rotations. The orthogonal matrix is found which expresses the spatial rotation produced by two successive vector Lorentz transformations and is applied to the Thomas precession of an accelerated frame relative to an inertial one. The method used is basically that outlined in Mollers book.

The justification and selection of scientific theories

This paper is a critique of a project, outlined by Laudan et al. (1986) recently in this journal, for empirically testing philosophical models of change in science by comparing them against the historical record of actual scientific practice. While the basic idea of testing such models of change in the arena of science is itself an appealing one, serious questions can be raised about the suitability of seeking confirmation or disconfirmation for large numbers of specific theses drawn from a massive list of claims abstracted from the writings of a few philosophers of science. The present paper discusses what one might reasonably expect from a model of change in science and then compares some clusters of theses from Laudan et al. with developments in recent theoretical physics. The results suggest that such straightforward testing of theses may be largely inconclusive.

Quantum tunneling times: A crucial test for the causal program?

It is generally believed that Bohms version of quantum mechanics is observationally equivalent to standard quantum mechanics. A more careful statement is that the two theories will always make the same predictions for any question or problem that is well posed in both interpretations. The transit time of a “particle” between two points in space is not necessarily well defined in standard quantum mechanics, whereas it is in Bohms theory since there is always a particle following a definite trajectory. For this reason tunneling times (in a scattering configuration through a potential barrier may be a situation in which Bohms theory can make a definite prediction when standard quantum mechanics can make none at all. I summarize some of the theoretical and experimental prospects for an unambiguous comparison in the hope that this question will engage the attention of more physicists, especially those experimentalists who now routinely actually do gedanken experiments.

Is there just one possible world? Contingency vs the bootstrap

Abstract As an example of what might be considered a candidate for an interesting and significant development in the methodology of recent science, I examine some of the epistemological and ontological commitments of the bootstrap conjecture of high energy theoretical physics. This conjecture holds that a well defined but infinite set of self-consistency conditions determines uniquely the entities or paticles which can exist. That is, once we are given any partial information about the actually existing world, nothing else about that world is contingent or arbitrarily adjustable. This almost Leibnizian idea is implemented in S -matrix theory through a unitarity equation, which is a statement of conservation of probability. The S -matrix program is contrasted with quantum field theory which does have arbitrarily assignable quantities. In spite of the highly constrained structure of S -matrix theory, that theory makes far fewer ontological and epistemological assumptions than does quantum field theory.