scholarly journals The historical role of the Adiabatic Principle in Bohr's quantum theory

2016 ◽  
Vol 528 (7-8) ◽  
pp. 530-534
Author(s):  
Blai Pié i Valls ◽  
Enric Pérez
Keyword(s):  
Quantum Theory ◽  
Adiabatic Principle ◽  
Historical Role

Guiding Principles

2019 ◽  
pp. 205-258
Author(s):  
Anthony Duncan ◽  
Michel Janssen
Keyword(s):  
Quantum Theory ◽  
Classical System ◽  
Special Role ◽  
Quantum Numbers ◽  
Adiabatic Principle ◽  
Old Quantum Theory ◽  
Underlying Principle ◽  
Guiding Principles ◽  
Action Variables

The development of the complex of assumptions and methods now referred to as the “old quantum theory” mainly took place in the first five years following the introduction of the Bohr atomic model in 1913. Three guiding principles emerged that were used, sometimes in overlapping ways, to explain the flood of spectroscopic data that needed to be explained. First, quantization rules (or conditions) were proposed to single out the allowed orbital motions of electrons in atoms. These rules were derived in various forms by Planck, Sommerfeld, and Wilson, but were put into their most general form by Schwarzschild, who recognized the underlying principle as the quantization of the action variables of a multiply periodic classical system. Second, the special role of the action variables in quantization was given convincing support by the transfer of the adiabatic principle of mechanics to quantum theory (work primarily due to Paul Ehrenfest). Third, the correspondence principle, or statement of asymptotic coincidence of quantum and classical theory in the limit of large quantum numbers, originally introduced by Bohr in 1913 as a supporting argument for his quantization of angular momentum in his theory of the hydrogen atom, was extended by Bohr and Kramers to provide selection rules and approximate intensity predictions evening the regime low quantum numbers.

Fundamentality

2017 ◽  
Author(s):  
Richard Healey
Keyword(s):  
Quantum Theory ◽  
High Energy Physics ◽  
Physical Property ◽  
Natural World ◽  
High Energy ◽  
Quantum Field Theories ◽  
Fundamental Physics ◽  
The World ◽  
Energy Physics

The metaphor that fundamental physics is concerned to say what the natural world is like at the deepest level may be cashed out in terms of entities, properties, or laws. The role of quantum field theories in the Standard Model of high-energy physics suggests that fundamental entities, properties, and laws are to be sought in these theories. But the contextual ontology proposed in Chapter 12 would support no unified compositional structure for the world; a quantum state assignment specifies no physical property distribution sufficient even to determine all physical facts; and quantum theory posits no fundamental laws of time evolution, whether deterministic or stochastic. Quantum theory has made a revolutionary contribution to fundamental physics because its principles have permitted tremendous unification of science through the successful application of models constructed in conformity to them: but these models do not say what the world is like at the deepest level.

scholarly journals The Historical Role of Leviticus 25 in Naturalizing Anti-Black Racism

Religions ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 570
Author(s):  
James W. Watts
Keyword(s):  
Seventeenth Century ◽  
Early Modern ◽  
High Probability ◽  
Middle Eastern ◽  
American Colonies ◽  
History Of ◽  
Historical Role ◽  
Permanent Property

Leviticus 25:39–46 describes a two-tier model of slavery that distinguishes Israelites from foreign slaves. It requires that Israelites be indentured only temporarily while foreigners can be enslaved as chattel (permanent property). This model resembles the distinction between White indentured slaves and Black chattel slaves in the American colonies. However, the biblical influence on these early modern practices has been obscured by the rarity of citations of Lev. 25:39–46 in sixteenth- and seventeenth-century sources about slavery. This article reviews the history of slavery from ancient Middle Eastern antiquity through the seventeenth century to show the unique degree to which early modern institutions resembled the biblical model. It then exposes widespread knowledge of Leviticus 25 in early modern political and economic debates. Demonstrating this awareness shows with high probability that colonial cultures presupposed the two-tier model of slavery in Leviticus 25:39–46 to naturalize and justify their different treatment of White indentured slaves and Black chattel slaves.

scholarly journals Metabolic Surgery and Cancer Risk: An Opportunity for Mechanistic Research

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3183
Author(s):  
Edward R. Sauter ◽  
Brandy Heckman-Stoddard
Keyword(s):  
Weight Loss ◽  
Cancer Risk ◽  
Risk Reduction ◽  
Dramatic Improvement ◽  
Role Of Government ◽  
Sustained Weight Loss ◽  
Historical Role ◽  
Cancer Risk Reduction

Metabolic (bariatric) surgery (MBS) is recommended for individuals with a BMI > 40 kg/m2 or those with a BMI 35–40 kg/m2 who have one or more obesity related comorbidities. MBS leads to greater initial and sustained weight loss than nonsurgical weight loss approaches. MBS provides dramatic improvement in metabolic function, associated with a reduction in type 2 diabetes mellitus and cardiovascular risk. While the number of MBS procedures performed in the U.S. and worldwide continues to increase, they are still only performed on one percent of the affected population. MBS also appears to reduce the risk of certain obesity related cancers, although which cancers are favorably impacted vary by study, who benefits most is uncertain, and the mechanism(s) driving this risk reduction are mostly speculative. The goal of this manuscript is to highlight 1) emerging evidence that MBS influences cancer risk, and that the potential benefit appears to vary based on cancer, gender, surgical procedure, and likely other variables; 2) the role of the NIH in MBS research in T2DM and CV risk for many years, and more recently in cancer; and 3) the opportunity for research to understand the mechanism(s) by which MBS influences cancer. There is evidence that women benefit more from MBS than men, that MBS may actually increase the risk of colorectal cancer in both women and men, and there is speculation that the benefit in cancer risk reduction may vary according to which MBS procedure an individual undergoes. Herein, we review what is currently known, the historical role of government, especially the National Institutes of Health (NIH), in driving this research, and provide suggestions that we believe could lead to a better understanding of whether and how MBS impacts cancer risk, which cancers are impacted either favorably or unfavorably, the role of the NIH and other research agencies, and key questions to address that will help us to move the science forward.

scholarly journals The Invariant Set Postulate: a new geometric framework for the foundations of quantum theory and the role played by gravity

2009 ◽  
Vol 465 (2110) ◽  
pp. 3165-3185 ◽  
Author(s):  
T. N. Palmer
Keyword(s):  
Quantum Theory ◽  
Science Fiction ◽  
State Space ◽  
Fractal Geometry ◽  
Quantum Physics ◽  
Nonlinear Dynamical Systems ◽  
Physical Reality ◽  
Invariant Set ◽  
Geometric Framework

A new law of physics is proposed, defined on the cosmological scale but with significant implications for the microscale. Motivated by nonlinear dynamical systems theory and black-hole thermodynamics, the Invariant Set Postulate proposes that cosmological states of physical reality belong to a non-computable fractal state-space geometry I , invariant under the action of some subordinate deterministic causal dynamics D I . An exploratory analysis is made of a possible causal realistic framework for quantum physics based on key properties of I . For example, sparseness is used to relate generic counterfactual states to points p ∉ I of unreality, thus providing a geometric basis for the essential contextuality of quantum physics and the role of the abstract Hilbert Space in quantum theory. Also, self-similarity, described in a symbolic setting, provides a possible realistic perspective on the essential role of complex numbers and quaternions in quantum theory. A new interpretation is given to the standard ‘mysteries’ of quantum theory: superposition, measurement, non-locality, emergence of classicality and so on. It is proposed that heterogeneities in the fractal geometry of I are manifestations of the phenomenon of gravity. Since quantum theory is inherently blind to the existence of such state-space geometries, the analysis here suggests that attempts to formulate unified theories of physics within a conventional quantum-theoretic framework are misguided, and that a successful quantum theory of gravity should unify the causal non-Euclidean geometry of space–time with the atemporal fractal geometry of state space. The task is not to make sense of the quantum axioms by heaping more structure, more definitions, more science fiction imagery on top of them, but to throw them away wholesale and start afresh. We should be relentless in asking ourselves: From what deep physical principles might we derive this exquisite structure? These principles should be crisp, they should be compelling. They should stir the soul. Chris Fuchs ( Gilder 2008 , p. 335)

The historical role of the UN in the modern world

2021 ◽  
pp. 6-21
Author(s):  
L. Grishaeva
Keyword(s):  
International Law ◽  
New World ◽  
International Security ◽  
Modern World ◽  
World War ◽  
Global Organization ◽  
Global Problems ◽  
Historical Role ◽  
Historical Origins

The author writes about the historical role of the United Nations in the modern world. About the historical origins of many of the problems facing the UN at the present time. About the UN as a global organization with universal competence and a broad representative composition. On the UN Charter, which is the basis for the legitimacy of decision-making to maintain peace and strengthen international security. On the urgent need to restore the rule of international law in solving global problems. On the erosion of the Yalta system and the need to preserve the unique architecture of the UN. About the reasons allowing the UN to prevent a new world war for 75 years.

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