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Displaying entries 31 through 45 of 130 found.
Animate Cosmos > Information
The Digital and the Real Universe: Foundations of Natural Philosophy and Computational Physics.
A paper for a Contemporary Natural Philosophy collection by the Technical University of Munich “emeritus of excellence” scholar (search) which describes how our viable, developmental cosmos seems to be running some manner of informative program which serves to generate life’s long course from origins to humanities.
In the age of digitization, the world seems to be reducible to a digital computer. However, mathematically, modern quantum field theories do not only depend on discrete, but also continuous concepts. Ancient debates in natural philosophy on atomism versus the continuum are deeply involved in modern research on digital and computational physics. This example underlines that modern physics, in the tradition of Newton’s Principia Mathematica Philosophiae Naturalis, is a further development of natural philosophy with the rigorous methods of mathematics, measuring, and computing. We consider fundamental concepts of natural philosophy with mathematical and computational methods and ask for their ontological and epistemic status. The following article refers to the author’s new book, The Digital and the Real World: Computational Foundations of Mathematics, Science, Technology, and Philosophy (World Scientific, February 2019). (Abstract)
Animate Cosmos > Information > Quant Info
Relation between Observers and Effects of Number Valuation in Science.
A latest entry by the octogenarian Argonne National Laboratory mathematician (search) which continues his lifetime studies of quantum physical reality so as to distill a natural unification. See also a steady 21st century posting of his papers on the e-print site, along with work on quantum information theory.
This paper is a small step towards the goal of constructing a coherent theory of physics and mathematics together. It is based on two ideas, the localization of mathematical systems in space or space time, and the separation of the concepts of number from number value. The presence of a location dependent number value field affects theoretical descriptions of many physical and geometric quantities. The localization of mathematical systems and the separation of number from number value or meaning both emphasize the role of observers. Nothing, including numbers, has value or meaning to an unconscious observer. It is hoped that this work will lead to a better understanding of the relation between the foundations of mathematics and physics, and the role that observers play in this relation. (Abstract Excerpt)
Animate Cosmos > Information > Quant Info
Strasberg, Philipp, et al.
Quantum and Information Thermodynamics: A Unifying Framework Based on Repeated Interactions.
Physical Review X.
We cite this entry by PS, Gernot Schaller and Tobias Brandes, Technical University of Berlin, and Massimiliano Esposito, University of Luxembourg as an example of the fluid intersect of these several fields as this foundational phase continues to morph into identities and comprehensions far removed from 20th century rudiments.
We expand the standard thermodynamic framework of a system coupled to a thermal reservoir by considering a stream of independently prepared units repeatedly put into contact with the system. These units can be in any nonequilibrium state and interact with the system with an arbitrary strength and duration. We show that this stream constitutes an effective resource of nonequilibrium free energy, and we identify the conditions under which it behaves as a heat, work, or information reservoir. We discuss how nonautonomously driven systems, micromasers, lasing without inversion and the electronic Maxwell demon can be thermodynamically analyzed within our framework. (Abstract excerpt)
Animate Cosmos > Thermodynamics > quant therm
At this point, it is worth revisiting the debated question of whether quantum thermodynamics offers advantages (e.g., in terms of a higher power output or efficiency) in comparison to classical thermodynamics. There is ample evidence that states with quantum properties such as entanglement, coherence, or squeezing can be used to extract more work than from thermal states. However, this by no means implies that quantum thermodynamics outperforms classical thermodynamics. In the repeated interaction framework, the nonequilibrium free energy captures both quantum and classical effects, and we will now use it to analyze the thermodynamics of work extraction. (26)
Goold, John, et al.
The Role of Quantum Information in Thermodynamics: A Topical Review.
Journal of Physics A.
Five physicists with postings in Italy, Spain, Switzerland and the UK contribute forty pages to this whole scale revision of what constitutes nature’s deepest phase. It’s course spans from a rudimentary 20th century strangeness onto energetic and communicative features similar to every other universe stage and instance. See also Quantum and Information Thermodynamics by Philipp Strasberg, et al in Physical Review X (7/2, 2017).
This topical review article gives an overview of the interplay between quantum information theory and thermodynamics of quantum systems. We focus on several trending topics including the foundations of statistical mechanics, resource theories, entanglement in thermodynamic settings, fluctuation theorems and thermal machines. This is not a comprehensive review of the diverse field of quantum thermodynamics; rather, it is a convenient entry point for the thermo-curious information theorist. Furthermore this review should facilitate the unification and understanding of different interdisciplinary approaches emerging in research groups around the world. (Abstract)
Animate Cosmos > Fractal
Banda-Barragan, Wladimir, et al.
On the Dynamics and Survival of Fractal Clouds in Galactic Winds.
Astrophysicists posted in Germany, Ecuador, Australia, and Japan, surely a global galaxy, quantify how all manner of celestial, interstellar gaseous phenomena seem to draw upon and exhibit a common self-similar geometry.
Recent observations suggest that dense gas clouds can survive even in hot galactic winds. Here we show that the inclusion of turbulent densities with different statistical properties has significant effects on the evolution of wind-swept clouds. We compare uniform, fractal solenoidal, and fractal compressive cloud models in both 3D and 2D hydrodynamical simulations. By comparing the cloud properties at the destruction time, we find that dense gas entrainment is more effective in uniform clouds than in either of the fractal clouds, and it is more effective in solenoidal than in compressive models. (Abstract excerpt)
Animate Cosmos > Fractal
Kempkes, Sander, et al.
Design and Characterization of Electrons in a Fractal Geometry.
As the Abstract details, Utrecht University physicists deftly show how even atoms and electrons, in their dynamic forms, naturally take on this iterative patterning. We offer two comments. When this section was first posted in 2004, the presence of a common, natural self-similarity was spurious and patchy. Fifteen years later it has become robustly evident that every universal, atomic, and animate complexity is graced by this infinite iteration. Whomever in the cosmos are we peoples to consider and begin a second materiality by way of “artificial atoms.” See also in the same issue Quantum Fractals by Dario Bercioux and Ainhoa Iriguez.
Here, we show how arrays of artificial atoms can be defined by controlled positioning of CO molecules on a Cu (111) surface, and how these sites couple to form electronic Sierpiński fractals. We characterize the electron wavefunctions at different energies with scanning tunnelling microscopy and spectroscopy, and show that they inherit the fractional dimension. Wavefunctions delocalized over the Sierpiński structure decompose into self-similar parts at higher energy, and this scale invariance can also be retrieved in reciprocal space. Our results show that electronic quantum fractals can be artificially created by atomic manipulation in a scanning tunnelling microscope. Moreover, the rational concept of artificial atoms can readily be transferred to planar semiconductor electronics, allowing for the exploration of electrons in a well-defined fractal geometry, including interactions and external fields. (Abstract)
Animate Cosmos > Fractal
Evolution of the Early Universe in the Scale Invariant Theory.
The Geneva Observatory astronomer (search) expands his collegial quantification of a universally repetitious self-similarity onto the whole evolutionary cosmos. See also The Growth of the Density Fluctuations in the Scale-Invariant Vacuum Theory by AM and Vesselin Gueorguiev at 1811.03495.
Analytical solutions are obtained for the early cosmological phases in the scale invariant models with curvature k=0. The physical properties in the radiative era are derived from conservation laws and compared to those of current standard models. The critical runs of the temperature and of the expansion rate of the scale invariant models with low densities, are quite similar at the time of nucleosynthesis to those of standard models, leading to the same freezing number ratio of neutrons to protons. These results are consistent with the fact that the scale invariant models appear to not require the presence of dark matter. (Abstract)
Animate Cosmos > Fractal
Von Korff, Modest and Thomas Sander.
Molecular Complexity Calculated by Fractal Dimension.
Nature Scientific Reports.
Scientific Computing Drug Discovery, Idorsia Pharmaceuticals, Switzerland researchers achieve another novel recognition that nature’s proclivity to adopt and display a self-similar, iterative essence can be traced even to molecular and atomic forms and sub-structures.
Molecular complexity is an important characteristic of organic molecules for drug discovery. How to calculate molecular complexity has been discussed in the scientific literature for decades. It was known from early on that the numbers of substructures that can be cut out of a molecular graph are of importance. However, it was never realized that the cut-out substructures show self-similarity to the parent structures. Such a series shows self-similarity similar to fractal objects. The fractal dimension of a molecule is a new matter constant that incorporates all features that are currently known to be important for describing molecular complexity.(Abstract)
Animate Cosmos > Astrobiology
During our work on repetitive molecular features we realized that every molecular substructure displays self-similarity to its parent structure. Self-similarity means that an object is similar to a part of itself. Let us derive the concept of self-similarity for organic molecules at the example of n-hexane, a linear alkane. A linear alkane consists of a chain of carbon atoms saturated with hydrogen atoms. Removing one of the two outmost carbon-atoms and the connecting bond creates a new chain with one bond less. To the chain carbon-atom from where the bond was removed, a hydrogen atom has to be added for completing the saturation of the chain. (2)
Kolb, Vera, ed.
Handbook of Astrobiology.
Boca Raton: CRC Press,
The editor is a University of Wisconsin astrochemist and author for these fertile fields. This volume is an 850 page survey to date all about Earth and cosmic life definitions, multifaceted origins, early evolutions, biochemicals and microbes in space, planetary habitability, whence intelligence, exoEarth searches, ethical issues and educative methods. For example Mind in the Universe by David Duner, Where Are They by Nikos Prantzos, The Evolution of Habitability by Charles Lineweaver, et al, The Origin of Life by Iris Fry, Complex Organic Molecules in Space by Sun Kwok, and Communication as the Main Characteristic of Life by Guenther Witzany (search).
Animate Cosmos > Astrobiology
Organics in the Solar System.
The University of Hong Kong prolific researcher and longtime advocate of astrobiochemical science continues to catalog how profusely our cosmic nature fills itself with all the vital substances that life needs to evolve and learn.
Complex organics are now commonly found in meteorites, comets, asteroids, planetary satellites, and interplanetary dust particles. The chemical composition and possible origin of these organics are presented. Specifically, we discuss the possible link between Solar System organics and the complex organics synthesized during the late stages of stellar evolution. Implications of extraterrestrial organics on the origin of life on Earth and the possibility of existence of primordial organics on Earth are also discussed. (Abstract)
Animate Cosmos > exoearths
Andrews, Sean, et al.
The Disk Substructures at High Angular Resolution Project (DSHARP): 1. Motivation, Sample, Calibration, and Overview.
Astrophysical Journal Letters.
An introduction to Focus on DSHARP Results, a 10 paper collection herein about the project and its first round of findings. Their significance is noted in Science as Hints of Young Planets Puzzle Theorists by Daniel Clery (362/1337, 2018), see second quote.
We introduce the Disk Substructures at High Angular Resolution Project (DSHARP), one of the initial Large Programs conducted with the Atacama Large Millimeter/submillimeter Array (ALMA). The primary goal is to find and characterize substructures in the spatial distributions of solid particles for a sample of 20 nearby protoplanetary disks, using very high resolution observations of their 240 GHz continuum emission. These data provide a first look at the small-scale disks that are relevant to planet formation, their prevalence, morphologies, spatial scales, spacings, symmetry, and amplitudes, with a variety of disk and stellar hosts. Here we discuss the motivation for the project, describe the survey design and the sample properties, detail the observations and data calibration, highlight some basic results, and provide a general overview of the key conclusions that are presented in more detail in a series of accompanying articles. (Abstract excerpt)
Animate Cosmos > exoearths
HL Tau, a mere stripling of a star at no more than 1 million years old, was swaddled in a surprise. Four years ago, the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile revealed rings and gaps in a bright disk of dust around HL Tau—apparently swept clean by unseen planets that had formed millions of years earlier than astronomers thought possible. But now, an ALMA survey of 20 disks around nearby young stars suggests the precocious planets around HL Tau are no anomalies. The results, published in 10 papers last week in The Astrophysical Journal Letters, suggest disks with rings, gaps, and other features are the norm, not an exception—a result that will keep theorists busy for years. (Clery Summary)
Universal Life: An Inside Look Behind the Race to Discover Life Beyond Earth.
New York: Oxford University Press,
The Carnegie Institute for Science, Washington, DC astrophysicist and author is also chair of NASA’s Exoplanet Exploration Analysis Group. A veteran of individual and management contributions to national and worldwide exoplanet programs, this volume details the administrative machinations that went on so this endeavor to could find myriad exoworlds suggestive of a cosmic vitality. A special theme is the Kepler Space Telescope and what it took by its main advocate William Borucki to make it happen and succeed.
We now know that Earth-like planets are universal, and we expect that life will be just as universal, even if it is primarily microbial, as earth life was for most of its history. Considering the wide variety of exoplanets found to date, far beyond the imagination of the most fertile science fiction writers, we can only dream about the weird life forms that might inhabit these worlds and about how equally weird we would appear to them. (192)
Animate Cosmos > exoearths
Gelino, Dawn and Jason Wright.
NASA and the Search for Technosignatures.
The 70 page main report from a September 2018 Workshop on how we Earthlings might look for and validly detect the presence of exo-civilizations with technical capacities. Some sections are Pulsed Radio, Continuous Wave Radio, Laser, Searches, also Limits of Megastructures, Waste Heat for Stars and Galaxies, and much more as our human to Anthropo sapience is just beginning to explore cosmic neighborhoods.
Bornholdt, Stefan and Stuart Kauffman.
Ensembles, Dynamics, and Cell Types: Revisiting the Statistical Mechanics Perspective on Cellular Regulation.
University of Bremen and Institute for Systems Biology, Seattle senior theorists look back 50 years to review Kauffman’s 1969 paper Metabolic Stability and Epigenesis in Randomly Constructed Genetic Nets (Journal of Theoretical Biology, 22/3, Abstract below). His 1993 work The Origins of Order played a major part in establishing the field of complex system studies. This posting continues its Self-Organization and Selection in Evolution subtitle by adding a statistical mechanics basis for biological regulation, along with selective effects. Into 2019 his prescient glimpses are well proven as we now know that gene regulatory networks do seek a self-organized criticality (search Bryan Daniels, Universality, Autocatalytic sections and elsewhere).
Genetic regulatory networks control ontogeny. For fifty years Boolean networks have served as models of such systems, ranging from ensembles of random Boolean networks as models for generic properties of gene regulation to working dynamical models of a growing number of sub-networks of real cells. At the same time, their statistical mechanics has been thoroughly studied. Here we recapitulate their original motivation in the context of current theoretical and empirical research. We discuss ensembles of random Boolean networks whose dynamical attractors model cell types. There is now strong evidence that genetic regulatory networks are dynamically critical, and that evolution is exploring the critical sub-ensemble. The generic properties of this sub-ensemble predict essential features of cell differentiation. Thus, the theory correctly predicts a power law relationship between the number of cell types and the DNA contents per cell, and a comparable slope. (2019 Abstract excerpt)
Proto-organisms probably were randomly aggregated nets of chemical reactions. The hypothesis that contemporary organisms are also randomly constructed molecular automata is examined by modeling the gene as a binary (on-off) device and studying the behavior of large, randomly constructed nets of these binary “genes”. The results suggest that, if each “gene” is directly affected by two or three other “genes”, then such random nets behave with great order and stability; undergo behavior cycles whose length predicts cell replication time as a function of the number of genes per cell; and under the stimulus of noise are capable of differentiating directly from any mode of behavior to at most a few other modes of behavior. The possibility of a general theory of metabolic behavior is suggested. (1969 SK Abstract excerpt)
Lesne, Annick and Michel Lagues.
Scale Invariance: From Phase Transitions to Turbulence.
Parisian physicists achieve a dedicated volume to express current realizations of nature’s own propensity to reliably repeat in kind the same structures and dynamics across universe to human scales, indeed from physics to people. By way of mathematic theories, albeit in abstractions as self-organized criticality, a robust veracity of a fractal-like “universality” is described from cosmic condensed matter to chemical, polymeric realms, biological systems, and onto somatic physiologies. See also From Newton to Mandelbrot by D. Stauffer, E. Stanley, and A. Lesne (Springer 2017) for a further excursion.
During a century from the Van der Waals mean field description of gases in the 1870s until the introduction of the renormalization group (RG) in the 1970s, thermodynamics and statistical physics were unable to account for the incredible universality observed in critical phenomena. The success of RG techniques is not only to solve this challenge of critical behaviour in thermal transitions but to introduce useful tools across a wide field where a system exhibits scale invariance. Since then, a new physics of scaling laws and critical exponents allows quantitative descriptions of numerous occasions, ranging from phase transitions to earthquakes, polymer conformations, heartbeat rhythm, diffusion, interface growth and roughening, DNA sequence, dynamical systems, chaos and turbulence. The chapters are jointly written by an experimentalist and a theorist.