Inductive Warrant

2021 ◽  
pp. 30-67
Author(s):  
Mark Wilson
Keyword(s):  
Twentieth Century ◽  
Quantum Theory ◽  
Classical Mechanics ◽  
Significant Degree ◽  
Central Argument ◽  
Diagnostic Work

But Hertz’s suggestions did not address his original “small metaphysics” conflicts in a credible manner. The alternative resolution that material scientists currently favor supplies an alternative paradigm upon which this book will later elaborate. To this end, the present chapter reviews the intellectual circumstances that Hertz confronted and why they were important to him. He displayed a keen eye for delicate detail in his diagnostic work, in a manner that should serve as a sterling model of conceptual detective work whenever it is wanted. But the depth of his insights has been frequently misunderstood by later generations, largely due to a greatly diminished form of “classical mechanics” that became popular in the twentieth century because of the parochial requirements of quantum theory. Within this reduced setting, Hertz’s motivating problems disappear, not because they have been solved, but because they have been ignored. As an aftereffect, many philosophers writing today confidently believe that they understand what “the worlds of classical mechanics are like,” although these rash presumptions embody a significant degree of simplistic misrepresentation. The present chapter outlines the forgotten background required to appreciate Hertz’s conceptual puzzles as he confronted them. These details are not required for the central argument of the book, but they nicely illustrate the natural contexts from which “small metaphysics” puzzles characteristically emerge within a gradually evolving discourse.

Subsequent and Subsidiary? Rethinking the Role of Applications in Establishing Quantum Mechanics

2015 ◽  
Vol 45 (5) ◽  
pp. 641-702 ◽  
Author(s):  
Jeremiah James ◽  
Christian Joas
Keyword(s):  
Molecular Structure ◽  
Quantum Mechanics ◽  
Quantum Theory ◽  
Classical Mechanics ◽  
Theory Construction ◽  
Science Pedagogy ◽  
Old Quantum Theory ◽  
The Common ◽  
Complete Quantum

As part of an attempt to establish a new understanding of the earliest applications of quantum mechanics and their importance to the overall development of quantum theory, this paper reexamines the role of research on molecular structure in the transition from the so-called old quantum theory to quantum mechanics and in the two years immediately following this shift (1926–1928). We argue on two bases against the common tendency to marginalize the contribution of these researches. First, because these applications addressed issues of longstanding interest to physicists, which they hoped, if not expected, a complete quantum theory to address, and for which they had already developed methods under the old quantum theory that would remain valid under the new mechanics. Second, because generating these applications was one of, if not the, principal means by which physicists clarified the unity, generality, and physical meaning of quantum mechanics, thereby reworking the theory into its now commonly recognized form, as well as developing an understanding of the kinds of predictions it generated and the ways in which these differed from those of the earlier classical mechanics. More broadly, we hope with this article to provide a new viewpoint on the importance of problem solving to scientific research and theory construction, one that might complement recent work on its role in science pedagogy.

scholarly journals Relativistic quantum mechanics

1932 ◽  
Vol 136 (829) ◽  
pp. 453-464 ◽  
Keyword(s):  
Quantum Mechanics ◽  
Quantum Theory ◽  
Classical Theory ◽  
Correspondence Principle ◽  
Relativistic Quantum ◽  
Classical Mechanics ◽  
Hamiltonian Function ◽  
Relativistic Quantum Mechanics ◽  
Classical Electrodynamics ◽  
Quantum Phenomena

The steady development of the quantum theory that has taken place during the present century was made possible only by continual reference to the Correspondence Principle of Bohr, according to which, classical theory can give valuable information about quantum phenomena in spite of the essential differences in the fundamental ideas of the two theories. A masterful advance was made by Heisenberg in 1925, who showed how equations of classical physics could be taken over in a formal way and made to apply to quantities of importance in quantum theory, thereby establishing the Correspondence Principle on a quantitative basis and laying the foundations of the new Quantum Mechanics. Heisenberg’s scheme was found to fit wonderfully well with the Hamiltonian theory of classical mechanics and enabled one to apply to quantum theory all the information that classical theory supplies, in so far as this information is consistent with the Hamiltonian form. Thus one was able to build up a satisfactory quantum mechanics for dealing with any dynamical system composed of interacting particles, provided the interaction could be expressed by means of an energy term to be added to the Hamiltonian function. This does not exhaust the sphere of usefulness of the classical theory. Classical electrodynamics, in its accurate (restricted) relativistic form, teaches us that the idea of an interaction energy between particles is only an approxi­mation and should be replaced by the idea of each particle emitting waves which travel outward with a finite velocity and influence the other particles in passing over them. We must find a way of taking over this new information into the quantum theory and must set up a relativistic quantum mechanics, before we can dispense with the Correspondence Principle.

Canonical quantization of free fields

2021 ◽  
pp. 70-98
Author(s):  
Iosif L. Buchbinder ◽  
Ilya L. Shapiro
Keyword(s):  
Field Theory ◽  
Quantum Theory ◽  
Electromagnetic Fields ◽  
Classical Theory ◽  
Canonical Quantization ◽  
Classical Mechanics ◽  
Scalar Fields ◽  
Complex Scalar ◽  
Spinor Fields ◽  
Free Fields

This chapter discusses canonical quantization in field theory and shows how the notion of a particle arises within the framework of the concept of a field. Canonical quantization is the process of constructing a quantum theory on the basis of a classical theory. The chapter briefly considers the main elements of this procedure, starting from its simplest version in classical mechanics. It first describes the general principles of canonical quantization and then provides concrete examples. The examples include the canonical quantization of free real scalar fields, free complex scalar fields, free spinor fields and free electromagnetic fields.

scholarly journals The Oxford Questions on the foundations of quantum physics

2013 ◽  
Vol 469 (2157) ◽  
pp. 20130299 ◽  
Author(s):  
G. A. D. Briggs ◽  
J. N. Butterfield ◽  
A. Zeilinger
Keyword(s):  
Twentieth Century ◽  
Quantum Theory ◽  
Quantum System ◽  
Quantum Physics ◽  
Empirical Success ◽  
Sense Of Wonder

The twentieth century saw two fundamental revolutions in physics—relativity and quantum. Daily use of these theories can numb the sense of wonder at their immense empirical success. Does their instrumental effectiveness stand on the rock of secure concepts or the sand of unresolved fundamentals? Does measuring a quantum system probe, or even create, reality or merely change belief? Must relativity and quantum theory just coexist or might we find a new theory which unifies the two? To bring such questions into sharper focus, we convened a conference on Quantum Physics and the Nature of Reality. Some issues remain as controversial as ever, but some are being nudged by theory's secret weapon of experiment.

Einstein: the classical physicist

2005 ◽  
Vol 59 (3) ◽  
pp. 255-271 ◽  
Author(s):  
J.S Rowlinson
Keyword(s):  
Nineteenth Century ◽  
Twentieth Century ◽  
Quantum Theory ◽  
Statistical Mechanics ◽  
Late Nineteenth Century ◽  
Classical Physics ◽  
Foundations Of Physics ◽  
Late Nineteenth

Einstein is remembered for his contributions to the re-ordering of the foundations of physics in the first years of the twentieth century. Much of his achievement was, however, based on the classical physics of the late nineteenth century and it was his work on statistical mechanics that underlay his first contributions to quantum theory. This essay is an account of an aspect of his achievement that is often overlooked.

scholarly journals Conceptual Problems in Bell's Inequality and Quantum Entanglement

2020 ◽  
Author(s):  
Ying-Qiu Gu
Keyword(s):  
Quantum Theory ◽  
Quantum Entanglement ◽  
Classical Mechanics ◽  
Bell State ◽  
Bell’S Inequality ◽  
Heisenberg Uncertainty Principle ◽  
Bell's Inequality ◽  
Micro Particles ◽  
Wave Particle Duality ◽  
New Interpretation

The description of the microscopic world in quantum mechanics is very different from that in classical physics, and there are some points of view that are contrary to intuition and logic. The first is the loss of reality, the behavior of micro particles shows randomness and hopping. The second is the loss of certainty, the conjugate physical variables of a system cannot be determined synchronously, they satisfy the Heisenberg uncertainty principle. The third is the non-local correlation. The measurement of one particle in the quantum entanglement pair will change the state of the other entangled particle simultaneously. In this paper, some concepts related to quantum entanglement, such as EPR correlation, quantum entanglement correlation function, Bell's inequality and so on, are analyzed in detail. Analysis shows that the mystery and confusion in quantum theory may be caused by the logical problems in its basic framework. Bell's inequality is only a mathematical theorem, but its physical meaning is actually unclear. The Bell state of quantum entangled pair may not satisfy the dynamic equation of quantum theory, so it cannot describe the true state of microscopic particles. In this paper, the correct correlation functions of spin entanglement pair and photonic entanglement pair are strictly derived according to normal logic. Quantum theory is a more fundamental theory than classical mechanics, and they are not parallel relation in logic. However, there are still some unreasonable contents in the framework of quantum theory, which need to be improved. In order to disclose the real relationship between quantum theory and classical mechanics, we propose some experiments which show the wave-particle duality simultaneously and provide intuitionistic teaching materials for the new interpretation of quantum theory.

scholarly journals El Mashreq francés en México. Patronazgo, propiedad y la lectura de los cuerpos en la Poscolonia / The French Mashreq in Mexico. Patronage, Property and Body readings in Postcolony

2017 ◽  
pp. 251
Author(s):  
Camila Pastor de Maria y Campos
Keyword(s):  
Twentieth Century ◽  
Privileged Position ◽  
French Mandate ◽  
Central Argument

Resumen: Este texto explora la ambivalencia en la producción estructural y discursiva de las posiciones de clase de migrantes que han circulado entre Líbano, Siria y México a lo largo del siglo veinte. Su argumento central es que la inscripción de su subalternidad como sujetos del mandato francés sobre el Mashreq, durante la primera mitad del siglo veinte, ha sido constitutiva de su acceso a una posición privilegiada en el contexto mexicano.Palabras clave: Mashreq, México, Francia, subalternidad, patronazgo. Abstract: This paper explores the ambivalence in the structural and discursive production of the class positions of migrants that have circulated between Lebanon, Syria and Mexico throughout the twentieth century. Its central argument is that the inscription of their subalternity as subjects of the French mandate on the Mashreq during the first half of the twentieth century has constituted their access to a privileged position in the Mexican context.Key words: Mashreq, México, France, Subalternity, Patronage.

Quantum logic

2018 ◽  
Author(s):  
Peter Forrest
Keyword(s):  
Quantum Theory ◽  
Quantum Logic ◽  
Algebraic System ◽  
Classical Mechanics ◽  
Remarkable Case ◽  
Von Neumann ◽  
Sentential Calculus ◽  
Subsequent Discussion ◽  
Term Logic ◽  
Formal Properties

The topic of quantum logic was introduced by Birkhoff and von Neumann (1936), who described the formal properties of a certain algebraic system associated with quantum theory. To avoid begging questions, it is convenient to use the term ‘logic’ broadly enough to cover any algebraic system with formal characteristics similar to the standard sentential calculus. In that sense it is uncontroversial that there is a logic of experimental questions (for example, ‘Is the particle in region R?’ or ‘Do the particles have opposite spins?’) associated with any physical system. Having introduced this logic for quantum theory, we may ask how it differs from the standard sentential calculus, the logic for the experimental questions in classical mechanics. The most notable difference is that the distributive laws fail, being replaced by a weaker law known as orthomodularity. All this can be discussed without deciding whether quantum logic is a genuine logic, in the sense of a system of deduction. Putnam argued that quantum logic was indeed a genuine logic, because taking it as such solved various problems, notably that of reconciling the wave-like character of a beam of, say, electrons, as it passes through two slits, with the thesis that the electrons in the beam go through one or other of the two slits. If Putnam’s argument succeeds this would be a remarkable case of the empirical defeat of logical intuitions. Subsequent discussion, however, seems to have undermined his claim.

Field theory, classical

2018 ◽  
Author(s):  
Mark Wilson
Keyword(s):  
Field Theory ◽  
Twentieth Century ◽  
Electromagnetic Field ◽  
Physical Quantity ◽  
General Framework ◽  
Degrees Of Freedom ◽  
Classical Mechanics ◽  
Electrical Strength ◽  
Mass Temperature

A physical quantity (such as mass, temperature or electrical strength) appears as a field if it is distributed continuously and variably throughout a region. In distinction to a ’lumped’ quantity, whose condition at any time can be specified by a finite list of numbers, a complete description of a field requires infinitely many bits of data (it is said to ’possess infinite degrees of freedom’). A field is classical if it fits consistently within the general framework of classical mechanics. By the start of the twentieth century, orthodox mechanics had evolved to a state of ontological dualism, incorporating a worldview where massive matter appears as ’lumped’ points which communicate electrical and magnetic influences to one another through a continuous intervening medium called the electromagnetic field. The problem of consistently describing how matter and fields function together has yet to be fully resolved.

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