Littérature scientifique sur le sujet « Analog cosmology »
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Articles de revues sur le sujet "Analog cosmology"
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Bilic, Neven, et Dijana Tolic. « Analogue cosmology in a hadronic fluid ». Facta universitatis - series : Physics, Chemistry and Technology 12, no 2 (2014) : 77–83. http://dx.doi.org/10.2298/fupct1402077b.
Texte intégralRésumé :
Analog gravity models of general relativity seem promising routes to providing laboratory tests of the foundation of quantum field theory in curved space-time. In contrast to general relativity, where geometry of a spacetime is determined by the Einstein equations, in analog models geometry and evolution of analog spacetime are determined by the equations of fluid mechanics. In this paper we study the analogue gravity model based on massless pions propagating in a expanding hadronic fluid. The analog expanding spacetime takes the form of an FRW universe, with the apparent and trapping horizons defined in the standard way.
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ELLIS, JOHN, D. V. NANOPOULOS et N. E. MAVROMATOS. « A STRING SCENARIO FOR INFLATIONARY COSMOLOGY ». Modern Physics Letters A 10, no 23 (30 juillet 1995) : 1685–98. http://dx.doi.org/10.1142/s0217732395001800.
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We describe a scenario for inflation in the framework of noncritical string theory, which does not employ an inflaton field. There is an exponential expansion of the volume of the Universe, induced by enormous entropy production in the early stages of cosmological evolution. This is associated with the loss of information carried by global string modes that cross the particle horizon. It is the same loss of information that induces irreversible time flow when target time is identified with the worldsheet Liouville mode. The resulting scenario for inflation is described by a string analog of the Fokker-Planck equation that incorporates diffusion and dissipative effects. Cosmological density perturbations are naturally small.
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Falomir, Horacio, Jorge Gamboa et Fernando Mendez. « A Noncommutative Model of Cosmology with Two Metrics ». Symmetry 12, no 3 (9 mars 2020) : 435. http://dx.doi.org/10.3390/sym12030435.
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We propose a bicosmology model which reduces to the classical analog of noncommutative quantum mechanics. From this point of view, one of the sources in the so modified Friedmann-Robertson- Walker equations is a kind of dark energy governed by a Chapligyn-like equation of state. The parameters of noncommutativity θ and B are interpreted in terms of the Planck area and a magnetic-like field, which presumably acts as a seed for magnetogenesis.
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Socorro, J., Luis O. Pimentel et Abraham Espinoza-García. « Classical Bianchi Type I Cosmology in K-Essence Theory ». Advances in High Energy Physics 2014 (2014) : 1–11. http://dx.doi.org/10.1155/2014/805164.
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We use one of the simplest forms of the K-essence theory and we apply it to the classical anisotropic Bianchi type I cosmological model, with a barotropic perfect fluid (p=γρ) modeling the usual matter content and with cosmological constantΛ. Classical exact solutions for anyγ≠1andΛ=0are found in closed form, whereas solutions forΛ≠0are found for particular values in the barotropic parameter. We present the possible isotropization of the cosmological model Bianchi I using the ratio between the anisotropic parameters and the volume of the universe. We also include a qualitative analysis of the analog of the Friedmann equation.
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GÓRKA, PRZEMYSŁAW, TOMASZ KOSTRZEWA et ENRIQUE G. REYES. « THE RELLICH LEMMA ON COMPACT ABELIAN GROUPS AND EQUATIONS OF INFINITE ORDER ». International Journal of Geometric Methods in Modern Physics 10, no 02 (5 décembre 2012) : 1220030. http://dx.doi.org/10.1142/s0219887812200307.
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Partially motivated by a class of nonlinear equations of interest for string theory, cosmology and p-adic analysis, we continue our research on Sobolev spaces on arbitrary locally compact abelian (LCA) groups. In this paper we focus on an analog for LCA groups of the classical Rellich compactness theorem. As an application, we prove the existence of continuous solutions to a generalized Euclidean bosonic string equation posed on a compact abelian group.
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Górka, Przemysław, Tomasz Kostrzewa et Enrique G. Reyes. « Sobolev Spaces on Locally Compact Abelian Groups : Compact Embeddings and Local Spaces ». Journal of Function Spaces 2014 (2014) : 1–6. http://dx.doi.org/10.1155/2014/404738.
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We continue our research on Sobolev spaces on locally compact abelian (LCA) groups motivated by our work on equations with infinitely many derivatives of interest for string theory and cosmology. In this paper, we focus on compact embedding results and we prove an analog for LCA groups of the classical Rellich lemma and of the Rellich-Kondrachov compactness theorem. Furthermore, we introduce Sobolev spaces on subsets of LCA groups and study its main properties, including the existence of compact embeddings intoLp-spaces.
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GIANG, DAN, et CHARLES C. DYER. « CONSTRUCTING AN INHOMOGENEOUS BRANEWORLD THROUGH SPACE–TIME MATCHING ». International Journal of Modern Physics D 18, no 12 (30 novembre 2009) : 1913–41. http://dx.doi.org/10.1142/s021827180901576x.
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We attempt to construct the braneworld analog of the cheese slice universe, an inhomogeneous cosmology constructed from alternating layers of Kasner and FLRW space–times. This construction is possible in four dimensions and we find that the energy conditions can be satisfied in the braneworld context. However, an extension into the bulk becomes more problematic. We use a 3 + 1 + 1 decomposition inspired by the ADM decompositions to show that structure is required in the bulk to support an inhomogeneous brane.
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Gorobey, Natalia, et Alexander Lukyanenko. « Ground state of the universe in quantum cosmology ». International Journal of Modern Physics A 31, no 02n03 (20 janvier 2016) : 1641014. http://dx.doi.org/10.1142/s0217751x16410141.
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We find a physical state of a closed universe with the minimal excitation of the universe expansion energy in quantum gravity. It is an analog of the vacuum state of the ordinary quantum field theory in the Minkowsky space, but in our approach an energy of space of a closed universe together with the energy of its matter content are minimized. This ground state is chosen among an enlarged set of physical states, compared with the ordinary covariant quantum gravity. In our approach, physical states are determined by weak constraints: quantum mechanical averages of gravitational constraint operators equal zero. As a result, they appear to be non-static in such a modification of quantum gravity. Quantum dynamics of the universe is described by Schrödinger equation with a cosmic time determined by weak gravitational constraints. In order to obtain the observed megascopic universe with the inflation stage just after its quantum beginning, a lot of the energy in the form of the inflaton scalar field condensate is prescribed to the initial state. Parameters of the initial state for a homogeneous model of the universe are calculated.
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K.Shchigolev, V. « Applying He's variational iteration method to FRW cosmology ». International Journal of Advanced Astronomy 7, no 2 (20 septembre 2019) : 39. http://dx.doi.org/10.14419/ijaa.v7i2.29428.
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This work is devoted to the investigation of Friedmann-Robertson-Walker (FRW) cosmological models with the help of the so-called Variational Iteration Method (VIM). For this end, we briefly recall the main equations of the cosmological models and the basic idea of VIM. In order to approbate the VIM in FRW cosmology and demonstrate the main steps in solving by this method, we consider the test example of the universe with dust for which the exact solution of the model is known. Then, a solution for the spatially flat FRW model of the universe filled with the dust and quintessence is obtained when the exact analytic solution cannot be found. A comparison of our solution with the corresponding numerical solution shows that it is of a high degree of accuracy. Moreover, the Dynamical System Analysis to the dynamics of the homogeneous and isotropic FRW universes is used as a special case of generalized Lotka–Volterra system where the competitive species are the barotropic fluids filling the Universe. With the help of VIM, we have found the iterative formulae for the density parameters of the cosmological analog of the generalized Lotka–Volterra set of equations. All solutions illustrated graphically by means of Maple software.
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Nojiri, Shin'ichi, et Sergei D. Odintsov. « Multiple lambda cosmology : Dark fluid with time-dependent equation of state as classical analog of cosmological landscape ». Physics Letters B 649, no 5-6 (juin 2007) : 440–44. http://dx.doi.org/10.1016/j.physletb.2007.02.042.
Texte intégralThèses sur le sujet "Analog cosmology"
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Rossoni, Mattos Diego. « Design and characterization of an 8gsps flash analog-to-digital converter for radio astronomy and cosmology applications ». Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14653/document.
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Un Convertisseur Analogique-Numérique (CAN) pour les applications spatiales en astrophysique et cosmologie a été développé au cours de cette thèse. Cette catégorie de circuits demande des bandes passantes très larges, de très hautes fréquences d'échantillonnage et une faible résolution. L’architecture flash a été retenue pour sa rapidité et sa bande passante. La fréquence d’échantillonnage est de 8GHz. La technologie utilisée est la CMOS 65 nm de chez STMicroeletronics. La conception a été faite en deux phases. Une première qui a amené à un prototype d'un échantillonneur-bloqueur et une deuxième qui a amené au CAN. Les deux prototypes ont été caractérisés et à partir de ces résultats des perspectives d'amélioration pour les nouvelles implémentations ont été retrouvées.Pour atteindre l'objectif final du CAN multi-bits (6-bit sont visés) il a été décidé de dessiner une première version du CAN avec la moitié de la résolution initialement prévue (on passe de 6-bit à 3-bit). L'objectif est de nous permettre d’analyser le comportement des blocs fonctionnels intégrés et ensuite passer à une deuxième voire troisième version pour remplir le cahier des charges initialAn Analog-to-Digital Converter (ADC) has been developed for astrophysical and cosmological applications. This class of circuits demands, especially in the millimeter wavelength domain, ultra wide bandwidths, ultra high sampling frequencies and a low resolution. The “flash” architecture has been chosen for its speed and bandwidth. This ADC samples at 8Gsps and it has been fabricated in 65nm CMOS technology from STMicroelectornics.The design has been done in two steps. The first was the prototype of a track-and-hold circuit. The second was the ADC. Both circuits have been characterized and from these results some perspectives for further improvements have been proposed.In order to achieve the final goal of the multi-bit ADC (6-bit resolution) we have decided to design a first prototype with half the final resolution, namely a 3-bit resolution ADC. Our idea was, with this first prototype, to conduct a first analysis of the behavior of the integrated functional blocks and, consequently, find the correct improvements required for the ADC final version
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Holanda, Rodrigo Fernandes Lira de. « Análogos clássicos para cosmologias relativísticas aceleradas : uma abordagem lagrangiana ». Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/14/14131/tde-19022008-172443/.
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Nesta dissertação, uma revisão dos modelos cosmológicos newtonianos e neo-newtonianos baseados na formulação da hidrodinâmica clássica é apresentada, com especial ênfase para os resultados básicos e as limitações mais importantes dessas abordagens. Em seguida, mostramos que a descrição Lagrangiana clássica proposta por Lima, Moreira e Santos (1998) para fluidos simples, pode ser generalizada para incluir modelos com misturas de fluidos, e portanto, cosmologias mais realísticas contendo bárions, matéria escura e energia escura, bem como qualquer forma de interação entre essas componentes. Neste trabalho propomos uma descrição lagrangiana clássica para modelos relativísticos do tipo FRW. Nesta descrição, o comportamento dinâmico do fator de escala a(t), como previsto pelas cosmologias relativísticas, é substituído pelo movimento unidimensional de uma partícula teste de massa m sob a ação de um potencial clássico, V(x), onde x é a coordenada unidimensional da partícula. O tratamento pode ser aplicado para os mais diversos cenários de energia escura. Para exemplificar, discutimos com detalhe os seguintes modelos contendo matéria escura e energia escura: XCDM, X(z)CDM, Lambda CDM, Lambda(t) e gás de Chaplygin. Por completeza, modelos multidimensionais do tipo FRW também são considerados. Em todos esses modelos, o parâmetro de curvatura k das seções espaciais das cosmologias determina a energia total da partícula teste pela relação, E=-mk/2, tal como ocorre nos modelos de fluidos simples. As propriedades dinâmicas associadas com o presente estágio de aceleração do universo são univocamente descritas em termos da função potencial do sistema. Finalmente, utilizando os dados da distância de luminosidade provenientes das supernovas do tipo Ia, discutimos como o potencial unidimensional pode ser reconstruído a partir das observações.In this dissertation, a review of the Newtonian and neo-Newtonian cosmological models based on the classical hydrodynamics formulation is presented with special emphasis to the basic results and the main limitations of such approaches. Next, we show that the classical Lagrangian description as proposed by Lima, Moreira & Santos (1998) for simple fluids, can be generalized to include fluid mixtures, and, therefore, more realistic cosmologies containing baryons, dark matter and dark energy, as well as, any kind of interaction among such components. In the lagrangian description, the dynamic behavior of the scale factor a(t), as predicted by the relativistic cosmologies, is replaced by the unidimensional motion of a test particle with mass m under the action of a classical potential, V(x), where x(t) is the coordinate of the particle. The treatment can be applied for many different scenarios of dark energy. In order to exemplify, we discuss with detail the following models containing dark matter and dark energy: XCDM, X(z)CDM, Lambda(t)CDM and the Chaplygin gas. For completeness, FRW type multidimensional models are also considered. For all these models, the curvature parameter k of the spatial sections in the relativistic cosmologies determines the total energy by the relation, E=-mk/2, as occurs in the simple fluid models. The dynamic property associated with the present accelerating stage of the Universe are univocally described in terms of the potential function of the system. Finally, by using the data from luminosity distance of supernovae type Ia, we discuss how the unidimensional potential can be reconstructed from the observations.
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Azevedo, Frankbelson dos Santos. « Contribution to the Study of Topological Defects and their Applications in Optics ». Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0198/document.
Texte intégralRésumé :
Dans cette thèse, notre étude porte sur les défauts topologiques en cosmologie et en physique de la matière condensée. Nous proposons d’étudier l’analogie entre les défauts qui apparaissent dans ces domaines. Par exemple, nous discutons l’analogie entre les cordes cosmiques et les disinclinaisons présentes dans les cristaux liquides. Cependant, nous concentrons nos efforts sur l’étude de la gravité et des aspects géométriques des défauts linéaires; cordes cosmiques «ondulées» et les disinclinaisons hyperboliques. Le champ gravitationnel des cordes ondulées est analogue à celui des cordes régulières mais avec un potentiel newtonien non nul. Pour cette raison, outre le fait que l’espace-temps a une géométrie conique, les cordes produisent également une traction gravitationnelle sur les objets situés dans leur voisinage. Ceci a pour conséquence: l’apparition de nouveaux effets en plus de la lentille gravitationnelle. En réalité, nous constatons que les champs massiques et non-massiques sont confinés au voisinage de la corde quand nous examinons la propagation non perpendiculaire à son axe. Cette affirmation est basée sur l’analyse des trajectoires et l’application du formalisme ondulatoire. Enfin, nous proposons la conception d’un guide d’onde optique ayant l’indice de réfraction spécifique permettant de simuler l’effet des cordes ondulées en laboratoire. Bien que la disinclinaison hyperbolique soit très similaire à la disinclinaison ordinaire, le milieu résultant est un métamatériau anisotrope dans lequel le rapport entre les permittivités ordinaire et extraordinaire est négatif. En fait, notre analyse concernant la disinclinaison hyperbolique étant très proche de la précédente pour la corde ondulée, nous appliquons alors le formalisme ondulatoire avec des traitements d’optique géométrique pour comprendre la propagation de la lumière. Nous trouvons que pour un agencement spécifique du champ directeur du cristal liquide hyperbolique, la lumière est confinée et dirigée vers l’axe du métamatériau. Plus précisément, on obtient un dispositif optique qui concentre les rayons de lumière, quelles que soient les conditions d’injectionIn this thesis, we study topological defects in cosmology and condensed matter physics. We propose to investigate the analogy between defects that appear in these two realms with respect to aspects of formation and gravity. For instance, we discuss the analogy between cosmic strings and disclinations existing in liquid crystals. In particular, we concentrate our efforts on the study of gravity/geometric aspects of two linear defects: wiggly cosmic string and hyperbolic disclination. The gravitational field of wiggly strings is analogous to the one of regular strings, but with a non-vanishing Newtonian potential. For that reason, besides the spacetime has conical geometry, the string also produces gravitational pullings on objects located in its vicinity. This new fact leads to new effects in addition to the already expected gravitational lensing. In fact, we find that both massive and massless fields are confined to the string when we examine non-perpendicular propagation to the string axis. This statement is based on the analysis of trajectories and by applying the wave formalism. Finally, we propose the design of an optical waveguide having the specific refractive index likely to simulate the effects of wiggly strings in the laboratory. Even though the hyperbolic disclination is very similar to the ordinary one, the resulting medium is an anisotropic metamaterial, in which the ratio between ordinary and extraordinary permittivities is negative. In fact, as our analysis concerning the hyperbolic medium is very close to the previous one for the wiggly string, we also apply the wave formalism together with geometrical optics treatment to understand how light propagates. Interestingly, we find that for one specific director field arrangement of the hyperbolic liquid crystal metamaterial, light is confined and directed to the metamaterial axis. More specifically, we come into possession of an optical device that concentrates light rays, no matter how they are injected in it
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ROITBERG, ALICE. « Gross-Pitaevskii hydrodynamics in Riemannian manifolds and application in Black Hole cosmology ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2023. https://hdl.handle.net/10281/404710.
Texte intégralRésumé :
In questa tesi ci si propone di analizzare le implicazioni fisiche della geometria dello spazio ambiente nel contesto dei condensati di Bose-Einstein (BEC) e le possibili applicazioni nell’ambito dei modelli analogici della cosmologia dei buchi neri. A tal fine si deriva la formulazione idrodinamica dell'equazione di Gross-Pitaevskii (GPE) nel caso di una generica varietà Riemanniana e si osserva la comparsa di una nuova forza, che dipende essenzialmente da due parametri: la geometria della varietà e le derivate prime del profilo di densità. Si studiano le condizioni stazionarie in relazione alla presenza di varietà a curvatura scalare negativa. Analizzando tali varietà si stabilisce una relazione esplicita tra le superfici a curvatura negativa e l'equazione di seno-Gordon, che risulta un'approssimazione della GPE nel caso di accoppiamento di fasi.
Assumendo condizioni stazionarie, si ottiene un nuovo tipo di equazioni di Einstein e si è spinti a ricercare altri legami tra le equazioni che governano i condensati e la cosmologia. A tal fine si considerano i BEC relativistici, che vengono utilizzati nello studio del comportamento dell'universo primordiale e della sua espansione. Facendo uso delle conoscenze ottenute nel caso di varietà Riemanniane generiche, otteniamo nuove equazioni di Einstein nel caso multi-dimensionale. Successivamente, si considerano i modelli analogici utilizzati per lo studio della formazione di buchi neri e per il calcolo della radiazione di Hawking. Attraverso un processo di linearizzazione si nota come sia possibile far emergere una metrica acustica Lorentziana che governi il moto delle fluttuazioni della fase; a questo scopo si considera il caso di un vortice dritto che presenta un profilo di densità in cui le derivate prime assumono un valore massimo all’interno del tubo vorticoso e la geometria dello spazio ambiente diventa rilevante. In questa situazione si scopre che è effettivamente possibile far emergere una metrica Lorentziana, e si propongono alcune approssimazioni utili per la sua determinazione esplicita.
Infine, vengono presentate alcune osservazioni conclusive su possibili direzioni di ricerca future, quali lo studio dell'evoluzione delle superfici isofase in casi relativistici e lo studio dei condensati sottoposti a torsione.In this thesis we analyze the physical implications of the geometry of the ambient space in the context of Bose-Einstein condensates (BECs) and possible applications to the field of analogue models in the cosmology of black holes. To this end we derive the hydrodynamic formulation of the Gross-Pitaevskii equation (GPE) in the case of a generic Riemannian manifold. We observe the appearance of a new force, which essentially depends on two parameters: the geometry of the manifold and the first derivatives of the density profile. The stationary conditions are studied in relation to the presence of manifolds with negative scalar curvature. By analyzing these manifolds, an explicit relationship is established between the negatively curved surfaces and the sine-Gordon equation, which results in an approximation of the GPE in the presence of phase coupling. By assuming stationary conditions, we obtain a new type of Einstein field equations and we look for other possible connections between the equations governing condensates and cosmology. For this purpose, we consider relativistic BECs, that are used in the study of the early universe and its expansion, and we obtain Einstein equation in the multi-dimensional case. Then we consider the analogue models used for the study of the formation of black holes and for the calculation of Hawking radiation. Through a linearization process it is possible to derive a Lorentzian acoustic metric for the phase fluctuations; for this purpose, we consider the case of a straight vortex defect with a density profile where the first derivatives have maximum value inside the vortex tube and the geometry of the ambient space becomes relevant. In this situation it turns out that it is possible to determine a Lorentzian metric, and some useful approximations are proposed for its explicit computation. Finally, some concluding remarks are presented on possible future research directions, given by the study of the evolution of isophase surfaces in relativistic cases, and the study of condensates subject to twist.
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Geier, Kevin Thomas. « Probing Dynamics and Correlations in Cold-Atom Quantum Simulators ». Doctoral thesis, Università degli studi di Trento, 2022. http://hdl.handle.net/11572/351120.
Texte intégralRésumé :
Cold-atom quantum simulators offer unique possibilities to prepare, manipulate, and probe quantum many-body systems. However, despite the high level of control in modern experiments, not all observables of interest are easily accessible. This thesis aims at establishing protocols to measure currently elusive static and dynamic properties of quantum systems. The experimental feasibility of these schemes is illustrated by means of numerical simulations for relevant applications in many-body physics and quantum simulation. In particular, we introduce a general method for measuring dynamical correlations based on non-Hermitian linear response. This enables unbiased tests of the famous fluctuation-dissipation relation as a probe of thermalization in isolated quantum systems. Furthermore, we develop ancilla-based techniques for the measurement of currents and current correlations, permitting the characterization of strongly correlated quantum matter. Another application is geared towards revealing signatures of supersolidity in spin-orbit-coupled Bose gases by exciting the relevant Goldstone modes. Finally, we explore a scenario for quantum-simulating post-inflationary reheating dynamics by parametrically driving a Bose gas into the regime of universal far-from-equilibrium dynamics. The presented protocols also apply to other analog quantum simulation platforms and thus open up promising applications in the field of quantum science and technology.I simulatori quantistici ad atomi freddi offrono possibilità uniche per preparare, manipolare e sondare sistemi quantistici a molti corpi. Tuttavia, nonostante l'alto livello di controllo raggiunto negli esperimenti moderni, non tutte le osservabili di interesse sono facilmente accessibili. Lo scopo di questa tesi è quello di stabilire protocolli per misurare delle proprietà statiche e dinamiche dei sistemi quantistici attualmente inaccessibili. La fattibilità sperimentale di questi schemi è illustrata mediante simulazioni numeriche per applicazioni rilevanti nella fisica a molti corpi e nella simulazione quantistica. In particolare, introduciamo un metodo generale per misurare le correlazioni dinamiche basato su una risposta lineare non hermitiana. Ciò consente test imparziali della famosa relazione fluttuazione-dissipazione come sonda di termalizzazione in sistemi quantistici isolati. Inoltre, sviluppiamo tecniche basate su ancilla per la misura di correnti e correlazioni di corrente, consentendo la caratterizzazione della materia quantistica fortemente correlata. Un'altra applicazione è orientata a rivelare l'impronta della supersolidità nei gas Bose con accoppiamento spin-orbita eccitando il corrispondente modo di Goldstone. Infine, esploriamo uno scenario per la simulazione quantistica della dinamica di riscaldamento post-inflazione modulando parametricamente un gas Bose e portandolo nel regime della dinamica universale lontana dall'equilibrio. I protocolli presentati si applicano anche ad altre piattaforme di simulazione quantistica analogica e aprono quindi applicazioni promettenti nel campo della scienza e della tecnologia quantistica.
Quantensimulatoren auf Basis ultrakalter Atome eröffnen einzigartige Möglichkeiten zur Präparation, Manipulation und Untersuchung von Quanten-Vielteilchen-Systemen. Trotz des hohen Maßes an Kontrolle in modernen Experimenten sind jedoch nicht alle interessanten Observablen auf einfache Weise zugänglich. Ziel dieser Arbeit ist es, Protokolle zur Messung aktuell nur schwer erfassbarer statischer und dynamischer Eigenschaften von Quantensystemen zu etablieren. Die experimentelle Realisierbarkeit dieser Verfahren wird durch numerische Simulationen anhand relevanter Anwendungen in der Vielteilchenphysik und Quantensimulation veranschaulicht. Insbesondere wird eine allgemeine Methode zur Messung dynamischer Korrelationen basierend auf der linearen Antwort auf nicht-hermitesche Störungen vorgestellt. Diese ermöglicht unabhängige Tests des berühmten Fluktuations-Dissipations-Theorems als Indikator der Thermalisierung isolierter Quantensysteme. Darüber hinaus werden Verfahren zur Messung von Strömen und Strom-Korrelationen mittels Kopplung an einen Hilfszustand entwickelt, welche die Charakterisierung stark korrelierter Quantenmaterie erlauben. Eine weitere Anwendung zielt auf die Enthüllung spezifischer Merkmale von Supersolidität in Spin-Bahn-gekoppelten Bose-Einstein-Kondensaten ab, indem die relevanten Goldstone-Moden angeregt werden. Schließlich wird ein Szenario zur Quantensimulation post-inflationärer Thermalisierungsdynamik durch die parametrische Anregung eines Bose-Gases in das Regime universeller Dynamik fern des Gleichgewichts erschlossen. Die dargestellten Protokolle lassen sich auch auf andere Plattformen für analoge Quantensimulation übertragen und eröffnen damit vielversprechende Anwendungen auf dem Gebiet der Quantentechnologie.
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Reyburn, Duncan. « Chestertonian dramatology ». Thesis, University of Pretoria, 2012. http://hdl.handle.net/2263/30301.
Texte intégralRésumé :
This study proposes an answer to the question of what the contemporary relevance of the writings of GK Chesterton (1874-1936) may be to the field of visual culture studies in general and to discourse on visual hermeneutics in particular. It contends that Chesterton’s distinctive hermeneutic strategy is dramatology: an approach rooted in the idea that being, which is disclosed to itself via language, has a dramatic, storied structure. It is this dramatology that acts as an answer to any philosophical outlook that would seek to de-dramatise the hermeneutic experience. The structure of Chesterton’s dramatology is unpacked via three clear questions, namely the question of what philosophical foundation describes his horizon of understanding, the question of what the task or goal of his interpretive process is and, finally, the question of what tools or elements shape his hermeneutic outlook. The first question is answered via an examination of his cosmology, epistemology and ontology; the second question is answered by the proposal that Chesterton’s chief aim is to uphold human dignity through his defenses of the common man, common sense and democracy; and the third question is answered through a discussion of the three principles that underpin his rhetoric, namely analogy, paradox and defamiliarisation. After proposing the structure of Chesterton’s dramatology via these considerations, the study offers one application of this dramatology to Terrence Malick’s film 'The tree of life' (2011). This is sustained in terms of the incarnational paradox between mystery and revelation that acts as the primary tension and hermeneutic key in Chesterton’s work.Thesis (PhD)--University of Pretoria, 2012.
Visual Arts
unrestricted
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Radermacher, Katharina Maria. « Strong Cosmic Censorship and Cosmic No-Hair in spacetimes with symmetries ». Doctoral thesis, KTH, Matematik (Avd.), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-220400.
Texte intégralRésumé :
This thesis consists of three articles investigating the asymptotic behaviour of cosmological spacetimes with symmetries arising in Mathematical General Relativity. In Paper A and B, we consider spacetimes with Bianchi symmetry and where the matter model is that of a perfect fluid. We investigate the behaviour of such spacetimes close to the initial singularity ('Big Bang'). In Paper A, we prove that the Strong Cosmic Censorship conjecture holds in non-exceptional Bianchi class B spacetimes. Using expansion-normalised variables, we further show detailed asymptotic estimates. In Paper B, we prove similar estimates in the case of stiff fluids. In Paper C, we consider T2-symmetric spacetimes satisfying the Einstein equations for a non-linear scalar field. To given initial data, we show global existence and uniqueness of solutions to the corresponding differential equations for all future times. In the special case of a constant potential, a setting which is equivalent to a linear scalar field on a background with a positive cosmological constant, we investigate in detail the asymptotic behaviour towards the future. We prove that the Cosmic No-Hair conjecture holds for solutions satisfying an additional a priori estimate, an estimate which we show to hold in T3-Gowdy symmetry.Denna avhandling består av tre artiklar som undersöker det asymptotiska beteendet hos kosmologiska rumstider med symmetrier som uppstår i Matematisk Allmän Relativitetsteori. I Artikel A och B studerar vi rumstider med Bianchi symmetri och där materiemodellen är en ideal fluid. Vi undersöker beteendet av sådana rumstider nära ursprungssingulariteten ('Big Bang'). I Artikel A bevisar vi att den Starka Kosmiska Censur-förmodan håller för icke-exceptionella Bianchi klass B-rumstider. Med hjälp av expansions-normaliserade variabler visar vi detaljerade asymptotiska uppskattningar. I Artikel B visar vi liknande uppskattningar för stela fluider. I Artikel C betraktar vi T2-symmetriska rumstider som uppfyller Einsteins ekvationer för ett icke-linjärt skalärfält. För givna begynnelsedata visar vi global existens och entydighet av lösningar till motsvarande differentialekvationer för all framtid. I det speciella fallet med en konstant potential, en situation som motsvarar ett linjärt skalärfält på en bakgrund med en positiv kosmologisk konstant, undersöker vi i detalj det asymptotiska beteendet mot framtiden. Vi visar att den Kosmiska Inget-Hår-förmodan håller för lösningar som uppfyller en ytterligare a priori uppskattning, en uppskattning som vi visar gäller i T3-Gowdy-symmetri.
QC 20171220
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Lacoste, Frédéric. « L'oiseau dans la poésie de Saint-John Perse, Kenneth White et Philippe Jaccottet : une pensée analogique au service du mystère ». Bordeaux 3, 2006. https://extranet.u-bordeaux-montaigne.fr/memoires/diffusion.php?nnt=2006BOR30021.
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La question de l'oiseau dans la poésie contemporaine se pose avec une certaine évidence. Impossible, semble-t-il, d'ouvrir un recueil de poèmes sans tomber à de nombreuses reprises sur des références explicites à l'oiseau : à son vol bien sûr, mais aussi à son chant, à sa présence discrète mais permanente. Comment expliquer cette re��currence dans la production contemporaine ? Et qu'est-ce qui constitue la singularité de l'oiseau dans le règne animal ? Après avoir justifié le rapprochement des trois poètes de notre corpus, nous avons fondé notre travail selon des perspectives analogiques et transdisciplinaires. Renouant à un certain degré avec la mystique médiévale, la poésie cherche les frontières de l'homme dans l'univers-macrocosme. L'oiseau, qui semble une limite ultime pour le psychisme humain, nous permet de redéfinir l'animalité selon un principe de "consanguinité" (Saint-John Perse). Contre la propension moderne à l'émiettement, au dispersé, au catalogique, cette pensée analogique à l'œuvre dans la production poétique de nos auteurs, cherche à reconstituer la trame et à "recoudre l'univers". La dimension métaphysique, souvent non revendiquée chez nos poètes, reste ainsi constamment sous-jacente. Au-delà d'une lecture du réel qui s'appuie sur la précision de la science, une "autre dimension", proche de l'Ouvert rilkéen, imprègne leurs œuvres. L'oiseau, à travers les motifs du vol et du chant, dessine alors les contours d'une poétique liée à la modernité esthétiqueThe question of the bird in contemporary poetry seems to be obvious. It's really impossible to open a collection of poems without seeing lots of explicit references to the bird : his fly, his singing, and his discreet but permanent presence. How to explain this recurrence in contemporary production ? And what's the foundation of the bird's particularity in the animal kingdom ? After justifying the connection of the three poets of our corpus, we based our work on analogical and transdiciplinary viewpoints. Reviving the medieval mysticism, poetry looks for the limits of human nature in the world-macrocosm. The bird, that seems the last limit for the human psychism, allows us to redefine animality in accordance with a principle of "consanguinity" (Saint-John Perse). Against the modern proclivity to dispersion and catalogue, this analogical thought circulating in the poems of our authors, wants to reconstruct the weft, to "sew up the universe". The metaphysical dimension, that is not often clearly claimed by our poets, is always underlying. Beyond a description of the real world, that is leaning on the precision of the science, another dimension, verging on rilkean "Ouvert", impregnates their works. The bird, through the patterns of the flight and the singing, draws the lines of poetics linked by aesthetic modernity
Livres sur le sujet "Analog cosmology"
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Cosmology and self in the Apostle Paul : The material spirit. Oxford : Oxford University Press, 2010.
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War and ethics in the ancient Near East : Military violence in light of cosmology and history. Berlin : Walter de Gruyter, 2009.
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Annihilation or renewal ? : The meaning and function of new creation in the book of Revelation. Tübingen : Mohr Siebeck, 2011.
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Mashhoon, Bahram. Nonlocal Newtonian Cosmology. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198803805.003.0010.
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We explore some of the cosmological implications of nonlocal gravity (NLG) theory, in which nonlocality is due to the gravitational memory of past events. Memory dies out in space and time. The fading of memory in time implies that in NLG the strength of the gravitational interaction must decrease with cosmic time. In the Newtonian regime of NLG, the nonlocal character of gravity simulates dark matter in spiral galaxies and clusters of galaxies. However, dark matter is considered indispensable as well for structure formation in standard models of cosmology. Can nonlocal gravity solve the problem of structure formation in cosmology without recourse to dark matter? In this chapter, a beginning is made in this direction by extending nonlocal gravity in the Newtonian regime to the cosmological domain. The nonlocal analog of the Zel’dovich solution is formulated and the consequences of the resulting nonlocal Zel’dovich model are investigated in detail.
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Wittman, David M. Beyond the Schwarzschild Metric. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199658633.003.0019.
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General relativity explains much more than the spacetime around static spherical masses.We briefly assess general relativity in the larger context of physical theories, then explore various general relativistic effects that have no Newtonian analog. First, source massmotion gives rise to gravitomagnetic effects on test particles.These effects also depend on the velocity of the test particle, which has substantial implications for orbits around black holes to be further explored in Chapter 20. Second, any changes in the sourcemass ripple outward as gravitational waves, and we tell the century‐long story from the prediction of gravitational waves to their first direct detection in 2015. Third, the deflection of light by galaxies and clusters of galaxies allows us to map the amount and distribution of mass in the universe in astonishing detail. Finally, general relativity enables modeling the universe as a whole, and we explore the resulting Big Bang cosmology.
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Schenck, Kenneth L. Cosmology and Eschatology in Hebrews : The Settings of the Sacrifice. Cambridge University Press, 2007.
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Schenck, Kenneth L. Cosmology and Eschatology in Hebrews : The Settings of the Sacrifice. Cambridge University Press, 2009.
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Schenck, Kenneth L. Cosmology and Eschatology in Hebrews : The Settings of the Sacrifice. Cambridge University Press, 2008.
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Schenck, Kenneth L. Cosmology and Eschatology in Hebrews : The Settings of the Sacrifice. Cambridge University Press, 2010.
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Schenck, Kenneth L. Cosmology and Eschatology in Hebrews : The Settings of the Sacrifice. Cambridge University Press, 2007.
Trouver le texte intégralChapitres de livres sur le sujet "Analog cosmology"
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« THE GOLD ANALOGY IN THE TIMAEUS ». Dans Platonic cosmology, 99–107. BRILL, 1985. http://dx.doi.org/10.1163/9789004320642_006.
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Anderson, Judith H. « Proportional Thinking in Kepler’s Science of Light ». Dans Light and Death. Fordham University Press, 2017. http://dx.doi.org/10.5422/fordham/9780823272778.003.0006.
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Light is at the center of Kepler’s optics, astronomy, and cosmology. Verbal and mathematical analogy, whether as concept, proportion, or both, is crucial to his methodology and his habits of thought. Kepler is an intellectual hybrid who combines Neoplatonic and perspectivist ideas about light with mathematical and physical discoveries anticipating those of Descartes and Newton. Kepler is strikingly engaged with the interface of the immaterial with the material that light effects, as well as with correspondences and other connections between the celestial and terrestrial realms. Analogy, the salient means of linking the known with the unknown, the abstract with the sensible, is conspicuous throughout his work. This chapter focuses on Kepler’s study of light, geometric optics, and their bearing on the observation of astronomical phenomena. Both Donne and Milton were acquainted with Kepler’s ideas (as with Spenser’s).
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Allen, Edward. « Nocturne ». Dans Forms of Late Modernist Lyric, 243–78. Liverpool University Press, 2022. http://dx.doi.org/10.3828/liverpool/9781789622423.003.0011.
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This chapter is about the night song, or nocturne, and the extent to which it has provided J. H. Prynne with a formal correlative for his nocturnal habits. It did so at a crucial moment in the poet’s career – the 1960s – just as he was composing the lyrics that would eventually find a home in The White Stones (1969). Those years witnessed significant strides in space exploration – particularly for the Soviet Union and for the United States – just as they did for political causes of one kind and another, including the Civil Rights movement. Prynne was attentive to such movements, with the result that the nocturne became in his hands a vehicle for thinking about the sorts of macro-historical developments that others (Ezra Pound, Charles Olson) had once explored in the epic form. The chapter is about the politics of cosmology, then, but it is also about the longer history of nocturne-writing. As well as touching on poets central to the evolving genre, the chapter looks to other media such as visual art and music (James McNeill Whistler’s paintings, Fryderyk Chopin’s piano writing) in order to assess the kinds of analogy that might help to thicken a description of the nocturne genre.
Actes de conférences sur le sujet "Analog cosmology"
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PORTO, RAFAEL A., et A. ZEE. « REASONING BY ANALOGY : ATTEMPTS TO SOLVE THE COSMOLOGICAL CONSTANT PARADOX ». Dans Quantum Mechanics, Elementary Particles, Quantum Cosmology and Complexity. WORLD SCIENTIFIC, 2010. http://dx.doi.org/10.1142/9789814335614_0035.
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Marshall, Oriel, Rita Tojeiro et Anne-Marie Weijmans. « Demonstrating cosmological and Doppler redshift in the classroom ». Dans Symposium on Space Educational Activities (SSAE). Universitat Politècnica de Catalunya, 2022. http://dx.doi.org/10.5821/conference-9788419184405.098.
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Cosmology is often a difficult subject to teach as it can involve many confusing and sometimes abstract concepts. One particular topic with many existing misconceptions and difficulties surrounding it is redshift, specifically the difference between Doppler shift (due to the peculiar velocities of galaxies) and cosmological redshift (due to the expansion of the side). Redshift of galaxies, despite being an extremely useful and interesting scientific tool, can often become a tedious subject to teach as it is largely theoretical and usually does not include demonstrations or interaction in the classroom. It can be challenging to understand, and therefore also challenging to explain, the differences between Doppler and cosmological redshift, often leading to this distinction being overlooked entirely. The set of demonstrations developed during this astrophysics masters project, along with the accompanying presentation, worksheet, and teacher notes, aim to explain both Doppler and cosmological redshift clearly and in an engaging and memorable way. The demonstrations use remote control vehicles to represent peaks of a travelling wave of light. When demonstrating Doppler shift, the vehicles are released from a plastic board that is being pulled away, representing a receding source of light. When demonstrating cosmological redshift, the vehicles are driven along a wide stretchy exercise band, representing a section of the expanding Universe through which this wave of light is travelling. This teaching resource will introduce interactive learning, proven to be very effective when teaching astronomy, and provides a useful and fun physical analogy to demonstrate an often-misunderstood subject.
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ANDRADE, GIOVANI LUZ, RAMON ALVES DOS SANTOS, IAN LIMA SANTANA et CARLOS TAKIYA. « SOBRE A RELAÇÃO ENTRE A FÍSICA DE PARTÍCULAS E A COSMOLOGIA : UMA ABORDAGEM E PROPOSTA DIDÁTICA PARA O ENSINO MÉDIO ». Dans Brazilian Congress. brazco, 2020. http://dx.doi.org/10.51162/brc.dev2020-00041.
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Neste trabalho e feita uma descricao da relacao existente entre a Fisica de Particulas e a Cosmologia e, nesse interim, e realizada uma abordagem basica dos conceitos envolvidos nessa relacao, bem como propostas didatica e experimental para o ensino medio. Nessas propostas, abordamos o uso de livros de divulgacao cientifica como material complementar para o ensino medio e uma atividade experimental que permite uma analogia da expansao do universo. Mostra-se neste estudo que, a introducao de obras de divulgacao como material complementar em sala de aula proporciona um grande potencial para o processo de ensino e aprendizagem. Ademais, apresentada a proposta didatica de atividade experimental, pode-se dizer que a mesma permite um entendimento mais simples sobre a expansao do universo, de forma que ela possibilite ao professor explicar de uma maneira mais didatica os conceitos envolvidos nesse processo para seus alunos e estes, ter maior participacao na aula e um entendimento mais claro desses conceitos.,
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Ferreira, Tiago D., João Novo, Orfeu Bertolami, Nuno A. Silva et Ariel Guerreiro. « Analogue cosmology : using techniques from nonlinear optics to study modified theories of gravity with non-minimal coupling between curvature and matter ». Dans Nonlinear Optics and Applications XII, sous la direction de Anatoly V. Zayats, Mario Bertolotti et Alexei M. Zheltikov. SPIE, 2021. http://dx.doi.org/10.1117/12.2592316.
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