Condensed Matter Physics

Solid state physics, the study of the physical properties of solid matter, was the most populous subfield of Cold War American physics. Despite prolific contributions to consumer and medical technology, such as the transistor and magnetic resonance imaging, it garnered less professional prestige and public attention than nuclear and particle physics. Solid State Insurrection argues that solid state physics was essential to securing the vast social, political, and financial capital Cold War physics enjoyed in the twentieth century. Solid state’s technological (...) bent, and its challenge to the “pure science” ideal many physicists cherished, helped physics as a whole respond more readily to Cold War social, political, and economic pressures. Its research kept physics economically and technologically relevant, sustaining its cultural standing and policy influence long after the sheen of the Manhattan Project had faded. (shrink)

O perspectivă contemporană asupra materiei, care ia în considerare toate entităţile ştiinţifice observabile, cu accent pe fenomene. În principiu, definiţia materiei se limitează la astfel de entităţi explorate de fizică. În funcţie de condiţiile termodinamice diferite, cum ar fi temperatura şi presiunea, materia poate exista în diferite “faze”, cele mai familiare fiind cele de solid, lichid, şi gaz. Alte faze pot fi cele de plasmă, superfluid, şi condensat Bose-Einstein. Atunci când materia trece dintr-o fază în alta, este supusă la ceea (...) ce este cunoscut ca tranziţie de fază, un fenomen studiat în termodinamică. -/- CUPRINS: -/- Natura atomică a materiei - Ipoteze atomice - Proprietățile atomilor - - Proprietăți nucleare - - Masa - - Forma și dimensiunea - - Dezintegrarea radioactivă - - Momentul magnetic - - Nivelurile energetice - - Valența și comportamentul legăturilor - - Stări - Imagistica atomică - Structura atomului - - Particule subatomice - - Nucleul - - Norul de electroni - Elemente chimice - - Descriere - - Originea elementelor - - Abundenţa - Tabelul periodic al elementelor - - Prezentare generală - - Metode de grupare - - - Grupe - - - Perioade - - - Blocuri - - - Metale, metaloide și nemetale - Izotopi (Variații, ocurența, aplicații) - - Proprietăți chimice și moleculare - - Proprietăți nucleare și stabilitatea - - Numere de izotopi per element - - Numerele de nucleoni pare și impare - - Existența în natură - - Aplicații ale izotopilor - - - Purificarea izotopilor - - - Utilizarea proprietăților chimice și biologice - - - Utilizarea proprietăților nucleare - Compuși și amestecuri - - Compuși chimici - - - Definiții - - - Legături și forțe - - Amestecuri - - - Caracteristicile amestecului - Molecule - - Legături - - - Covalente - - - Ionice - - Dimensiunea moleculară - - Geometria moleculară - - Spectroscopia moleculară - - Aspecte teoretice - Antimateria - - Definiție formală - - Istoria conceptului - - Notaţie - - Proprietăți - - Origine și asimetrie - Materia întunecată - - Definiție tehnică - - Compoziția materiei întunecate: barionică vs. nonbarionică - - - Materia barionică - - - Materia non-barionică - - - Agregarea materiei întunecate și obiectele dense de materie întunecată Solide - Microscopia cu ioni în câmp - - Introducere - - Design, limitări și aplicații - Structura cristalelor - - Celula unitară - - - Indicii Miller - - - Planuri și direcții - - - - Structuri cubice - Densitatea solidelor - - Istorie - - Măsurarea densității - - - Materiale omogene - - - Materiale heterogene - - - Materiale non-compacte - Elasticitatea - - Prezentare generală - - Elasticitatea liniară - - Aplicații - Rezistența materialelor - - Definiție - - Tipuri de sarcini - - Condiții de stres - - Condiții de rezistență - - Condiții de deformare - - Relațiile stres-deformare Lichide - Aplicații - Presiunea - - Definiție - - Unități - - Presiunea fluidelor - - Presiunea în lichid - - - Direcția presiunii lichidului - Flotabilitatea - Principiul lui Arhimede - - Formula - - Rafinare - Forțe în cazurile scufundării și plutirii - - Model simplificat - Stabilitatea statică - Flotarea - Principiul lui Pascal - - Definiție - - Explicaţie - - Butoiul lui Pascal - - Aplicațiile legii lui Pascal - Tensiunea superficială - - Cauze - - Efectele tensiunii de suprafață - - - Apa - - - Surfactanţi - Capilaritatea - - Fenomenul și fizica acțiunii capilare - - La plante și animale - - Exemple - - Înălțimea unui menisc - - Transportul lichidelor în medii poroase Gaze - Caracteristici fizice - Atmosfera - - Scurgeri de atmosferă - - Teren - - Compoziție - - Structura Pământului - - Circulație - - Importanța - - Presiunea atmosferică - - - Mecanism - - - Atmosfera standard - - - Presiunea medie a nivelului mării - - - Variația altitudinii - - - Variația locală - Barometru - - Tipuri - - - Barometre pe bază de apă - - - Barometre cu mercur - - - Barometru cu ulei de pompă de vid - - - Barometre aneroide - - - Barografe - - - Barometre MEMS - - Aplicații - - Barometre și calcularea presiunii atmosferice - Legea lui Boyle - - Istorie - - Definiție - - Relația cu teoria cinetică și gazele ideale - - Ecuaţia - - Sistemul respirator uman - Flotabilitatea în aer (Aerostate) - - Baloane - - Dirijabile - - Aerostate hibride - - Gaze flotante - - - Aer cald - Principiul lui Bernoulli - - Aplicații - - Efectul Coandă - - - Descoperire - - - Mecanismul efectului Coandă - - - Aplicații Plasma - Definiție - Proprietăți și parametri - - Grad de ionizare - - Temperaturi - - Plasme termice vs. nontermice - - Ionizare completă vs. incompletă - - Potențialul plasmei - - Magnetizare - - Comparația fazelor de plasmă și gaz - Plasma în natură, artificială și aplicații - - Plasmă în astronomie și astrofizică - - Plasma comună Schimbarea de fază - Clasificarea tranzițiilor de fază - - Clasificarea Ehrenfest - - Clasificarea modernă a tranzițiilor de fază - Proprietăți ale tranzițiilor de fază - - Puncte critice - - Simetria - - Exponenți critici și clase de universalitate - Evaporarea - - Teorie - - - Echilibru evaporativ - - Factorii care influențează rata de evaporare - Condensarea - - Inițiere - - Scenarii de reversibilitate - - Cele mai frecvente scenarii - - Cum este măsurată condensarea - - Aplicații ale condensării - - Adaptarea biologică - - Condensarea în construcția de clădiri - Ceaţa - - Definiție - - Formare - Nori - - Formarea și distribuția - - - Cum devine saturat aerul - - - Convergența de-a lungul zonelor cu presiune scăzută - - - Divergența de-a lungul zonelor de înaltă presiune - - Efecte asupra climei și atmosferei - Fierberea - - Tipuri - - - Nucleația - - - Fluxul de căldură critic - - - Tranziția - - - Filmul - - - Distilarea - - Fierberea vs. evaporarea - Înghețarea/Solidificarea - - Cristalizare - - Suprarăcirea - - Exotermicități - - Vitrificarea - - Expansiunea - - Înghețarea organismelor vii - - - Bacterii - - - Plante - - - Animale - - Conservarea alimentelor - Topirea - - Topirea ca o tranziție de fază de prim ordin - - Criteriile de topire - - Suprarăcirea - - Topirea solidelor amorfe (sticle) - Căldura latentă - - Folosire - - - Meteorologie - - Căldură latentă specifică Probleme nerezolvate - Fizica materiei condensate - Fizica plasmei Referințe Despre autor - Nicolae Sfetcu - - De același autor - - Contact Editura - MultiMedia Publishing. 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With the help of syncretiсs as a new philosophical logic, the philosophy of carriers, the theory of similarity and the theory of Infinite Hierarchical Nesting of Matter, the problems of modern physics are analyzed. We consider the classical and relativistic mechanics, the special and general theories of relativity, the theory of electromagnetic and gravitational fields, of weak and strong interactions. The goal is axiomatization of these theories, building models of elementary particles and of their interactions with each other. The main (...) obtained results are: description of the electrokinetic theory of the origin of magnetic fields in cosmic bodies; calculation of metric in the uniformly accelerated reference frame; the axiomatic construction of electrodynamics, Lorentz invariant (LITG) and covariant theories of gravitation (CTG); comparing CTG with the general theory of relativity and with the results of gravitational experiments. Among other results – the analysis of the properties of ether as the medium responsible for transfer of electromagnetic and gravitational waves, and derivation of the formula for entropy in a tensor form. For students and researchers, as well as for those interested in physical and philosophical problems. (shrink)

Despite the close connection between the central limit theorem and renormalization group (RG) methods, the latter should be considered fundamentally distinct from the kind of probabilistic framework associated with statistical mechanics, especially the notion of averaging. The mathematics of RG is grounded in dynamical systems theory rather than probability, which raises important issues with respect to the way RG generates explanations of physical phenomena. I explore these differences and show why RG methods should be considered not just calculational tools but (...) the basis for a physical understanding of complex systems in terms of structural properties and relations. (shrink)

This is an introduction to renormalization group methods in quantum field theory aimed at philosophers of science. review path integral methods, the relationship between early renormalization theory and renormalization group methods, and conceptual shifts in thinking about quantum field theory spurred by the development of renormalization group methods.

In this article we argue that idealizations and limiting cases in models play an exploratory role in science. Four senses of exploration are presented: exploration of the structure and representational capacities of theory; proof-of-principle demonstrations; potential explanations; and exploring the suitability of target systems. We illustrate our claims through three case studies, including the Aharonov-Bohm effect, the emergence of anyons and fractional quantum statistics, and the Hubbard model of the Mott phase transitions. We end by reflecting on how our case (...) studies and claims compare to accounts of idealization in the philosophy of science literature such as Michael Weisberg’s three-fold taxonomy. (shrink)

It has been recently debated whether there exists a so-called “easy road” to nominalism. In this essay, I attempt to fill a lacuna in the debate by making a connection with the literature on infinite and infinitesimal idealization in science through an example from mathematical physics that has been largely ignored by philosophers. Specifically, by appealing to John Norton’s distinction between idealization and approximation, I argue that the phenomena of fractional quantum statistics bears negatively on Mary Leng’s proposed path to (...) easy road nominalism, thereby partially defending Mark Colyvan’s claim that there is no easy road to nominalism. (shrink)

Various claims regarding intertheoretic reduction, weak and strong notions of emergence, and explanatory fictions have been made in the context of first-order thermodynamic phase transitions. By appealing to John Norton’s recent distinction between approximation and idealization, I argue that the case study of anyons and fractional statistics, which has received little attention in the philosophy of science literature, is more hospitable to such claims. In doing so, I also identify three novel roles that explanatory fictions fulfill in science. Furthermore, I (...) scrutinize the claim that anyons, as they are ostensibly manifested in the fractional quantum Hall effect, are emergent entities and urge caution. Consequently, it is suggested that a particular notion of strong emergence signals the need for the development of novel physical–mathematical research programs. (shrink)

Two approaches to understanding the idealizations that arise in the Aharonov–Bohm effect are presented. It is argued that a common topological approach, which takes the non-simply connected electron configuration space to be an essential element in the explanation and understanding of the effect, is flawed. An alternative approach is outlined. Consequently, it is shown that the existence and uniqueness of self-adjoint extensions of symmetric operators in quantum mechanics have important implications for philosophical issues. Also, the alleged indispensable explanatory role of (...) said idealizations is examined via a minimal model explanatory scheme. Last, the idealizations involved in the AB effect are placed in a wider philosophical context via a short survey of part of the literature on infinite and essential idealizations. (shrink)

This paper looks at the nature of idealizations and representational structures appealed to in the context of the fractional quantum Hall effect, specifically, with respect to the emergence of anyons and fractional statistics. Drawing on an analogy with the Aharonov–Bohm effect, it is suggested that the standard approach to the effects— the topological approach to fractional statistics—relies essentially on problematic idealizations that need to be revised in order for the theory to be explanatory. An alternative geometric approach is outlined and (...) endorsed. Roles for idealizations in science, as well as consequences for the debate revolving around so-called essential idealizations, are discussed. (shrink)

I present a novel approach to the scholarly debate that has arisen with respect to the philosophical import one should infer from scientific accounts of phase transitions by appealing to a distinction between representation understood as denotation, and faithful representation understood as a type of guide to ontology. It is argued that the entire debate is misguided, for it stems from a pseudo-paradox that does not license the type of claims made by scholars and that what is really interesting about (...) phase transitions is the manner by which they force us to rethink issues regarding scientific representation, idealizations, and realism. (shrink)

Recent discussions of emergence in physics have focussed on the use of limiting relations, and often particularly on singular or asymptotic limits. We discuss a putative example of emergence that does not fit into this narrative: the case of phonons. These quasi-particles have some claim to be emergent, not least because the way in which they relate to the underlying crystal is almost precisely analogous to the way in which quantum particles relate to the underlying quantum field theory. But there (...) is no need to take a limit when moving from a crystal lattice based description to the phonon description. Not only does this demonstrate that we can have emergence without limits, but also provides a way of understanding cases that do involve limits. (shrink)

The framework of effective field theory is a natural one in which to understand the claim that the spacetime of general relativity is an emergent low-energy phenomenon. I argue for a pragmatic understanding of EFT, given that the appropriate conception of emergence it suggests is necessarily epistemological in a sense. Analogue models of spacetime are examples of the top-down approach to EFT. They offer concrete illustrations of spacetime emergent within an EFT, and lure us toward a strong analogy between condensed (...) matter physics and GR. I argue that we should be wary of this strong analogy, not least because the pragmatic view of EFT places limits on how much we can legitimately draw from it. On the other hand, programs that treat GR as an EFT and calculate quantum corrections are an example of the bottom-up approach and are explicitly pragmatic in character. I explore what we may learn about the nature of emergent spacetime by comparing these two approaches. (shrink)

Atomistic metaphysics motivated an explanatory strategy which science has pursued with great success since the scientific revolution. By decomposing matter into its atomic and subatomic parts physics gave us powerful explanations and accurate predictions as well as providing a unifying framework for the rest of science. The success of the decompositional strategy has encouraged a widespread conviction that the physical world forms a compositional hierarchy that physics and other sciences are progressively articulating. But this conviction does not stand up to (...) a closer examination of how physics has treated composition, as a variety of case studies will show. (shrink)

It is commonly claimed that the universality of critical phenomena is explained through particular applications of the renormalization group. This article has three aims: to clarify the structure of the explanation of universality, to discuss the physics of such RG explanations, and to examine the extent to which universality is thus explained. The derivation of critical exponents proceeds via a real-space or a field-theoretic approach to the RG. Building on work by Mainwood, this article argues that these approaches ought to (...) be distinguished: while the field-theoretic approach explains universality, the real-space approach fails to provide an adequate explanation. (shrink)