Searcharxiv⌕ Search

SEARCH · Searcharxiv

Results for “physics.hist-ph”

Search indexed arXiv papers on artificial intelligence, large language models, computer vision and robotics. Read source abstracts and follow links to arXiv.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 811 records · Page 45Linked to original sources
arXiv2019

Strong emergence in condensed matter physics

This paper argues that the physics of condensed matter cannot be fully reduced to the supposedly fundamental quantum mechanical theory for all the atoms of which the system consists. In fact, there are many reasons to reject the idea that the world of physics is causally closed with everything being determined bottom-up by fundamental microscopic laws. This is illustrated by considering how condensed-matter theory is done in practice. It is never done by starting with a microscopic theory for the interaction of all the atoms of the system. Instead, approximations, plausible assumptions, intuitive models, and phenomenological theories are used to mathematically describe and explain the properties of systems that consist of a macroscopic number of particles. I argue that this is not merely a matter of convenience, but that there are fundamental and qualitative differences or even contradictions between the microscopic theory and the theory that is used in practice. The paper includes a list of arguments in favor of strong emergence and top-down causation within the realm of physics, and a response to several widespread objections against this view.

physics.hist-ph↗
arXiv2019

Scientific relations between Uruguay and Argentina in the 1920s: the exact sciences

The scientific career of Uruguayan theoretical physicist Enrique Loedel Palumbo in Argentina illustrates the intense intellectual exchange that existed between these neighboring countries in the first third of the twentieth century. In this paper we briefly discuss the scientific training of this scientist in Uruguay, his subsequent incorporation to the Institute of Physics of La Plata, in Buenos Aires, and his first steps in research under the tutelage of German professor Richard Gans.

physics.hist-ph↗
arXiv2019

Non-Associative Algebras and Quantum Physics -- A Historical Perspective

We review attempts by Pascual Jordan and other researchers, most notably Lawrence Biedenharn to generalize quantum mechanics by passing from associative matrix or operator algebras to non-associative algebras. We start with Jordan's work from the early 1930ies leading to Jordan algebras and the first attempt to incorporate the alternative ring of octonions into physics. Jordan's work on the octonions from 1932 till 1952 will be covered, discussing aspects of the exceptional Jordan algebra and how to express probabilities when working with the octonions and the exceptional Jordan algebra. From the 1950ies onwards Jordan and others also considered one-sided distributive systems like near-fields, near-rings, quasi-fields and exceptional Segal systems (the last two examples being not necessarily associative). As the set of non-linear operators forms a near-ring and even a near-algebra, this may be of interest for attempts to pass from a linear to a non-linear setting in the study of quantum mechanics. Moreover, ideas introduced in the late 1960ies to use non-power-associative algebras to formulate a theory of a minimal length will be covered. Lawrence Biedenharn's and Jordan's ideas related to non-power-associative octonionic matrix algebras will be briefly mentioned, a long section is devoted to a summary of Horst Rühaak's PhD thesis from 1968 on matrix algebras over the octonions. Finally, recent attempts to use non-associative algebras in physics will be described.

math-ph↗
arXiv2019

The ontological identity of empirical indiscernibles: Leibniz's methodological principle and its significance in the work of Einstein

This article explores the following methodological principle for theory construction in physics: if an ontological theory predicts two scenarios that are ontologically distinct but empirically indiscernible, then this theory should be rejected and replaced by one relative to which the scenarios are ontologically the same. I defend the thesis that this methodological principle was first articulated by Leibniz as a version of his principle of the identity of indiscernibles, and that it was applied repeatedly to great effect by Einstein in his development of the special and general theories of relativity. I argue for an interpretation of the principle as an inference to the best explanation, defend it against some criticisms, discuss its potential applications in modern physics, and explain how it provides an attractive middle ground in the debate between empiricist and realist philosophies of science.

physics.hist-ph↗
arXiv2019

How Nature is Conformable to Herself: A View from Quantum Cosmology

In his essay "Nature Conformable to Herself" the late Murray Gell-Mann expands on an observation of Newton that theories of seemingly disparate phenomena in the universe often make use of similar ideas and similar mathematical structure. Newton summarized that by saying that nature was very consonant and conformable to herself. This essay uses a model of quantum cosmology to illustrate how, why, and when nature is conformable to herself.

gr-qc↗
arXiv2019

Ontological Foundations of the Variational Principles and the Path Integral Formalism

In this paper, I consider the issue of how two mathematical models of modern physics, the variational principles and the quantum path integral formalism, relate to reality. I assume that the observed phenomena are consistent with the calculations because both of these models have some common ontological foundations. According to the hypothesis of the summation of coexisting alternative possibilities, at the quantum level, the system at once moves along all histories that possible in given boundary conditions. The actual history is a mere result of the summation of all these alternative possible histories. This resultant history differs from others with the minimal action and maximal probability. I observe this history as a macroscopic trajectory of the system.

physics.hist-ph↗
arXiv2019

Lev Lipatov: my friend and renowned physicist

These notes are written for the book "From the past to the future: the legacy of Lev Lipatov", editors: Jochen Bartels et all, which will be published by WS. I tried to share with you the atmosphere and the flavour of everyday life in Gribov's theory department, where Lev matured as an independent researcher and wrote all his breakthrough papers.

physics.hist-ph↗
arXiv2019

Is the Reality Criterion Analytic?

Tim Maudlin has claimed that EPR's Reality Criterion is analytically true. We argue that it is not. Moreover, one may be a subjectivist about quantum probabilities without giving up on objective physical reality. Thus, would-be detractors must reject QBism and other epistemic approaches to quantum theory on other grounds.

quant-ph↗
arXiv2019

Not the Earth, but its orbit: Andre Tacquet and the question of star sizes in a heliocentric universe

This paper consists of a translation of Andre Tacquet's discussion of the question of sizes of stars in a heliocentric universe, as published in his posthumous Opera Mathematica of 1668, along with introductory material and analysis. While Robert Hooke mentions Tacquet as one of the "great Anti-copernicans", who argued the question of star sizes against the heliocentric theory with "great vehemency and insulting", Tacquet's discussion has received only scant attention. The kernel of Tacquet's argument is that the absence of any detectable parallax in the stars, combined with the measured apparent sizes of the stars, means that, in a heliocentric universe, the sizes of stars compare to the size of Earth's orbit via the same proportion that they compare to the size of the Earth in a geocentric universe. The translated material presents this argument in a straightforward manner, insulting absent.

physics.hist-ph↗
arXiv2019

Challenges for the periodic systems of elements: chemical, historical and mathematical perspectives

Unveiling numerical trends among either atomic or equivalent weights that somehow preserved resemblances among elements was frequent in the 1860s. Standing out from the crowd, Meyer and Mendeleev went beyond numerical relationships, certainly motivated by a pedagogical aim. Both were after a system synthesizing the chemical knowledge of their times in an appealing way to be presented to chemistry students. Is it still the periodic system aiming at that? Is it really a map of the current chemistry landscape? Solving these questions entails addressing others such as: what is the periodic system? If it is about chemical elements, do we really know what a chemical element is? Is the system unique? How was and how is currently built up? Is it actually used to conduct chemical research? A suitable tool for chemical predictions? Or is it just a mnemotechnic for fancy trends? Does it have a limit, or multiple ones, instead? Let us try to address these questions and let us begin by analysing the concept of chemical element.

physics.hist-ph↗
arXiv2019

Straddling between determinism and randomness: Chaos theory vis-a-vis Leibniz

The problematic relationship between science and philosophy has, since the beginning of modernity, divided the world into two separate domains: nature and human. Some of today's schools of philosophy and epistemological inquiry have maintained a radical separation to the point where they refuse to maintain any commonality within the two. We argue that such a dichotomy will not only destroy the idea of the unity of knowledge from a theoretical perspective but, it will destroy a unified understanding of reality. This article is a critique of now mainstream belief of such dichotomy through re-reading of Leibniz's idea on the unity of knowledge. The distinctive feature of Leibniz's approach, which was specifically laid down in his correspondence with Clarke, is that his way of reasoning is philosophical as well as physical. In Leibniz's view what guarantees the soundness of philosophical principles cannot defy the laws of physics. We shall also demonstrate that Chaos Theory is consistent with the affinities of Leibniz's approach. The main focus of this article is on re-evaluating views on causal determinism and randomness as well as free will. The final claim of this article is that the natural world and human world follow the same causal deterministic laws, and that causal laws are however nonlinear. Knowledge of our reality should be rigorously sought in both the domains of humanities and natural sciences, but this causal determinism should distance itself from a simple linear causal model. What is thought of as random events or probabilistic events in the physical world, as well as in the human world, are not ontologically run by chance. The complexity and vastness of reality are such that our knowledge of reality always suffers a lack, and it is this lack of knowledge that is usually being called randomness.

physics.hist-ph↗
arXiv2019

Why Halley did not discover proper motion and why Cassini did

In 1717 Halley compared contemporaneous measurements of the latitudes of four stars with earlier measurements by ancient Greek astronomers and by Brahe, and from the differences concluded that these four stars showed proper motion. An analysis with modern methods shows that the data used by Halley do not contain significant evidence for proper motion. What Halley found are the measurement errors of Ptolemaios and Brahe. Halley further argued that the occultation of Aldebaran by the Moon on 11 March 509 in Athens confirmed the change in latitude of Aldebaran. In fact, however, the relevant observation was almost certainly made in Alexandria where Aldebaran was not occulted. By carefully considering measurement errors Jacques Cassini showed that Halley's results from comparison with earlier astronomers were spurious, a conclusion partially confirmed by various later authors. Cassini's careful study of the measurements of the latitude of Arcturus provides the first significant evidence for proper motion.

physics.hist-ph↗
arXiv2019

Historical and Philosophical Insights about General Relativity and Space-time from Particle Physics

Historians recently rehabilitated Einstein's "physical strategy" for General Relativity (GR). Independently, particle physicists similarly re-derived Einstein's equations for a massless spin 2 field. But why not a light \emph{massive} spin 2, like Neumann and Seeliger did to Newton? Massive gravities are bimetric, supporting conventionalism over geometric empiricism. Nonuniqueness lets field equations explain geometry but not \emph{vice versa}. Massive gravity would have blocked Schlick's critique of Kant's synthetic \emph{a priori}. Finally in 1970 massive spin 2 gravity seemed unstable or empirically falsified. GR was vindicated, but later and on better grounds. However, recently dark energy and theoretical progress have made massive spin 2 gravity potentially viable again.

physics.hist-ph↗
arXiv2019

How Dualists Should (Not) Respond to the Objection from Energy Conservation

The principle of energy conservation is widely taken to be a serious difficulty for interactionist dualism (whether property or substance). Interactionists often have therefore tried to make it satisfy energy conservation. This paper examines several such attempts, especially including E. J. Lowe's varying constants proposal, showing how they all miss their goal due to lack of engagement with the physico-mathematical roots of energy conservation physics: the first Noether theorem (that symmetries imply conservation laws), its converse (that conservation laws imply symmetries), and the locality of continuum/field physics. Thus the "conditionality response", which sees conservation as (bi)conditional upon symmetries and simply accepts energy non-conservation as an aspect of interactionist dualism, is seen to be, perhaps surprisingly, the one most in accord with contemporary physics (apart from quantum mechanics) by not conflicting with mathematical theorems basic to physics. A decent objection to interactionism should be a posteriori, based on empirically studying the brain.

physics.hist-ph↗
arXiv2019

Model Pluralism

This paper introduces and defends an account of model-based science that I dub model pluralism. I argue that despite a growing awareness in the philosophy of science literature of the multiplicity, diversity, and richness of models and modeling-practices, more radical conclusions follow from this recognition than have previously been inferred. Going against the tendency within the literature to generalize from single models, I explicate and defend the following two core theses: (i) any successful analysis of models must target sets of models, their multiplicity of functions within science, and their scientific context and history and (ii) for almost any aspect x of phenomenon y, scientists require multiple models to achieve scientific goal z.

physics.hist-ph↗
arXiv2019

A democratic Cosmos?

Despite the success of our best models in Theoretical Physics, especially concerning Cosmology and Particle Physics, we still face persistent challenges. Among them we have the cosmological singularity problem, understanding the late-time acceleration of the Universe, and comprehending the fundamental nature of time. We believe relevant new insights to tackle each of these issues may be found in the Philosophy of Cosmology. We elaborate on three philosophical principles that shall guide us on how to improve our current theories. They are the Copernican Principle for Scales, the Cosmological Heterarchical Principle and the Cosmological Principle of Irreversibility. Following these principles, and using some of our current physical theories as a proxy to implement them, we consider a new assessment of each of these challenges, and show how they may be either explained away, hinting towards new physics, or summarized in a new philosophical principle.

physics.hist-ph↗
arXiv2019

Edwin P. Hubble, astropolítico

Rather than offering chronologically ordered encyclopedic knowledge of a lifetime, only some of the most striking events of the existence of this well-known scientist are here pointed out. Sections: Life; Man of laws; Interest in philosophy; Astronomer, astrophysicist, cosmologist; The discovery of the expansion of the Universe; Reasonable doubt about the expansion; The astropolitician. Apart from his scientific ideas of cosmological scope, his worldview has been that of a pragmatic thinker with training in law, who converts science into a large company and the scientific hypothesis into a convenient truth that deserves to be defended and arrogated, although deep down it is known that such reasons are not exclusive or original and that there are also reasons to defend the opposite thing. ------ Más que ofrecer un conocimiento enciclopédico cronológicamente ordenado de toda una vida, señalaré solamente algunos de los eventos más llamativos de la existencia del ampliamente reconocido científico. Secciones: Vida; Hombre de leyes; Interés por la filosofía; Astrónomo, astrofísico, cosmólogo; El descubrimiento de la expansión del Universo; Duda razonable sobre la expansión; El astropolítico. Aparte de sus ideas científicas de alcance cosmológico, su cosmovisión ha sido la de un pensador pragmático con formación de abogado, que convierte la ciencia en una gran empresa y la hipótesis científica en una verdad conveniente que merece defenderse y arrogarse, aunque en el fondo se sepa que no son exclusivas ni originales tales razones y que hay también razones para defender lo contrario.

physics.hist-ph↗