Role of nonlinearity in non-Hermitian quantum mechanics: Description of linear quantum electrodynamics from the nonlinear Schrödinger-Poisson equation

2016 ◽  
Vol 131 (7) ◽  
Author(s):  
Gilbert C. Reinisch ◽  
Maxime Gazeau
Keyword(s):  
Quantum Mechanics ◽  
Poisson Equation ◽  
Quantum Electrodynamics ◽  
Nonlinear Schrödinger ◽  
Linear Quantum

Randomness and Complexity

2018 ◽  
Author(s):  
Steven E. Vigdor
Keyword(s):  
Quantum Mechanics ◽  
Natural Selection ◽  
Rna World ◽  
Biological Evolution ◽  
Variable Theory ◽  
Cosmological Natural Selection ◽  
Einstein Podolsky Rosen ◽  
World Hypothesis ◽  
Rna World Hypothesis

Chapter 7 describes the fundamental role of randomness in quantum mechanics, in generating the first biomolecules, and in biological evolution. Experiments testing the Einstein–Podolsky–Rosen paradox have demonstrated, via Bell’s inequalities, that no local hidden variable theory can provide a viable alternative to quantum mechanics, with its fundamental randomness built in. Randomness presumably plays an equally important role in the chemical assembly of a wide array of polymer molecules to be sampled for their ability to store genetic information and self-replicate, fueling the sort of abiogenesis assumed in the RNA world hypothesis of life’s beginnings. Evidence for random mutations in biological evolution, microevolution of both bacteria and antibodies and macroevolution of the species, is briefly reviewed. The importance of natural selection in guiding the adaptation of species to changing environments is emphasized. A speculative role of cosmological natural selection for black-hole fecundity in the evolution of universes is discussed.

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.

Bachelard, Gaston (1884–1962)

2018 ◽  
Author(s):  
Mary Tiles
Keyword(s):  
Twentieth Century ◽  
Quantum Mechanics ◽  
Literary Criticism ◽  
Philosophy Of Science ◽  
Relativity Theory ◽  
Creative Imagination ◽  
Scientific Objectivity ◽  
New Science ◽  
Poetic Imagination

One indication of the originality of Bachelard’s work is that he was famous for his writings both in the philosophy of science and on the poetic imagination. His work demonstrates his belief that the life of the masculine, work-day consciousness (animus), striving towards scientific objectivity through reasoning and the rectification of concepts, must be complemented by the life of a nocturnal, feminine consciousness (anima), seeking an expanded poetic subjectivity, as, in reverie, it creates the imaginary. In common with other scientist-philosophers writing in the first half of the twentieth century, Bachelard reflected on the upheavals wrought by the introduction of relativity theory and quantum mechanics. The views at which he arrived were, however, unlike those of his contemporaries; he argued that the new science required a new, non-Cartesian epistemology, one which accommodated discontinuities (epistemological breaks) in the development of science. It was only after he had established himself as one of France’s leading philosophers of science, by succeeding Abel Rey in the chair of history and philosophy of science at the Sorbonne, that Bachelard began to publish works on the poetic imagination. Here his trenchantly anti-theoretical stance was provocative. He rejected the role of literary critic and criticized literary criticism, focusing instead on reading images and on the creative imagination.

Philosophical Issues in (Sub)Disciplinary Contexts: The Case of Quantum Chemistry

2016 ◽  
Author(s):  
Kostas Gavroglu ◽  
Ana Simões
Keyword(s):  
Quantum Mechanics ◽  
Quantum Chemistry ◽  
Philosophical Problem ◽  
Ontological Status ◽  
Energy Resonance ◽  
Straightforward Application ◽  
History Of ◽  
Chemical Character ◽  
State Of Affairs

IN A WAY, QUANTUM chemistry was “born” as a philosophical problem: It was, of course, chemistry, but owed its scientific status to physics; it was physics with the promise of explaining all of chemistry. Thankfully, following P. A. M. Dirac’s verdict (1929), this state of affairs, at least some years after 1929, was for a future world, an almost utopian world. In the meantime, chemists, physicists, and mathematicians for about half a century defying Dirac’s soothing call that all is well, but only on principle, brought about a new subdiscipline and all the methodological, epistemological, and philosophical problems that go along with the formation of any subdiscipline. In this chapter we put forward a proposal as to how we can write the history of an “in-between” discipline such as quantum chemistry, suggesting that this proposal can be extended to other “in-between” disciplines. Then, we address the role of theory in chemistry, and specifically in quantum chemistry, including the issues surrounding the ontological status of theoretical entities, and proceed to discuss the implications of the introduction of computers in quantum chemistry and the concomitant reconceptualization of experiment. Finally, we reappraise the question of reductionism from the perspective of the practitioners of quantum chemistry. From the very beginning of the period when chemical problems were examined quantum mechanically, everyone involved in the subsequent developments tried to understand the chemical character of what was begotten in the encounter(s) of chemistry with quantum mechanics. Was quantum chemistry the subdiscipline for all those chemical problems formulated in the language of physics which could be dealt with by a straightforward application of quantum mechanics with, of course, the ensuing conceptual readjustments? Was it the case that chemical problems could be dealt with only through an intricate process of appropriation of quantum mechanics by the chemists’ culture? Furthermore, the development of quantum chemistry brought about new entities whose ontological status was continuously under negotiation: exchange energy, resonance, and orbitals were some of the more intriguing entities.

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