Libros de Física, página 33 de 363

Networks are everywhere, from the Internet, to social networks, and the genetic networks that determine our biological existence. Illustrated throughout in full colour, this pioneering textbook, spanning a wide range of topics from physics to computer science, engineering, economics and the social sciences, introduces network science to an interdisciplinary audience. From the origins of the six degrees of separation to explaining why networks are robust to random failures, the author explores how viruses like Ebola and H1N1 spread, and why it is that our friends have more friends than we do. Using numerous real-world examples, this innovatively designed text includes clear delineation between undergraduate and graduate level material. The mathematical formulas and derivations are included within Advanced Topics sections, enabling use at a range of levels. Extensive online resources, including films and software for network analysis, make this a multifaceted companion for anyone with an interest in network science.

This book is a treatise on time and on background independence in physics. It first considers how time is conceived of in each accepted paradigm of physics: Newtonian, special relativity, quantum mechanics (QM) and general relativity (GR). Substantial differences are moreover uncovered between what is meant by time in QM and in GR. These differences jointly source the Problem of Time: Nine interlinked facets which arise upon attempting concurrent treatment of the QM and GR paradigms, as is required in particular for a background independent theory of quantum gravity. A sizeable proportion of current quantum gravity programs - e.g. geometrodynamical and loop quantum gravity approaches to quantum GR, quantum cosmology, supergravity and M-theory - are background independent in this sense. This book's foundational topic is thus furthermore of practical relevance in the ongoing development of quantum gravity programs. This book shows moreover that eight of the nine facets of the Problem of Time already occur upon entertaining background independence in classical (rather than quantum) physics.By this development, and interpreting shape theory as modelling background independence, this book further establishes background independence as a field of study. Background independent mechanics, as well as minisuperspace (spatially homogeneous) models of GR and perturbations thereabout are used to illustrate these points.

You are reading the word "now" right now. But what does that mean? What makes the ephemeral moment "now" so special? Its enigmatic character has bedeviled philosophers, priests, and modern-day physicists from Augustine to Einstein and beyond. Einstein showed that the flow of time is affected by both velocity and gravity, yet he despaired at his failure to explain the meaning of "now." Equally puzzling: why does time flow? Some physicists have given up trying to understand, and call the flow of time an illusion, but the eminent experimentalist physicist Richard A. Muller protests. He says physics should explain reality, not deny it. In Now, Muller does more than poke holes in past ideas; he crafts his own revolutionary theory, one that makes testable predictions. He begins by laying out-with the refreshing clarity that made Physics for Future Presidents so successful-a firm and remarkably clear explanation of the physics building blocks of his theory: relativity, entropy, entanglement, antimatter, and the Big Bang. With the stage then set, he reveals a startling way forward.Muller points out that the standard Big Bang theory explains the ongoing expansion of the universe as the continuous creation of new space. He argues that time is also expanding and that the leading edge of the new time is what we experience as "now." This thought-provoking vision has remarkable implications for some of our biggest questions, not only in physics but also in philosophy-including the ongoing debate about the reality of free will. Moreover, his theory is testable. Muller's monumental work will spark major debate about the most fundamental assumptions of our universe, and may crack one of physics's longest-standing enigmas

From the reviews: "...useful for experts in mathematical physics...this is a very interesting book, which deserves to be found in any physical library." (OPTICS & PHOTONICS NEWS, July/August 2005

Quantum information theory is at the frontiers of physics, mathematics and information science, offering a variety of solutions that are impossible using classical theory. This book provides an introduction to the key concepts used in processing quantum information and reveals that quantum mechanics is a generalisation of classical probability theory. After a gentle introduction to the necessary mathematics the authors describe the geometry of quantum state spaces. Focusing on finite dimensional Hilbert spaces, they discuss the statistical distance measures and entropies used in quantum theory. The final part of the book is devoted to quantum entanglement - a non-intuitive phenomenon discovered by Schrodinger, which has become a key resource for quantum computation. This richly-illustrated book is useful to a broad audience of graduates and researchers interested in quantum information theory. Exercises follow each chapter, with hints and answers supplied.

This introductory text treats thermodynamics as an incomplete description of quantum systems with many degrees of freedom. Its main goal is to show that the approach to equilibrium - with equilibrium characterized by maximum ignorance about the open system of interest - neither requires that many particles nor is the precise way of partitioning, relevant for the salient features of equilibrium and equilibration. Furthermore, the text depicts that it is indeed quantum effects that are at work in bringing about thermodynamic behavior of modest-sized open systems, thus making Von Neumann's concept of entropy appear much more widely useful than sometimes feared, far beyond truly macroscopic systems in equilibrium. This significantly revised and expanded second edition pays more attention to the growing number of applications, especially non-equilibrium phenomena and thermodynamic processes of the nano-domain. In addition, to improve readability and reduce unneeded technical details, a large portion of this book has been thoroughly rewritten.

This book presents a unified approach to a rich and rapidly evolving research domain at the interface between statistical physics, theoretical computer science/discrete mathematics, and coding/information theory. It is accessible to graduate students and researchers without a specific training in any of these fields. The selected topics include spin glasses, error correcting codes, satisfiability, and are central to each field. The approach focuses on large random instances and adopts a common probabilistic formulation in terms of graphical models. It presents message passing algorithms like belief propagation and survey propagation, and their use in decoding and constraint satisfaction solving. It also explains analysis techniques like density evolution and the cavity method, and uses them to study phase transitions.

This book presents the Proceedings of the 15th International Conference on Non-Hermitian Hamiltonians in Quantum Physics, held in Palermo, Italy, from 18 to 23 May 2015. Non-Hermitian operators, and non-Hermitian Hamiltonians in particular, have recently received considerable attention from both the mathematics and physics communities. There has been a growing interest in non-Hermitian Hamiltonians in quantum physics since the discovery that PT-symmetric Hamiltonians can have a real spectrum and thus a physical relevance. The main subjects considered in this book include: PT-symmetry in quantum physics, PT-optics, Spectral singularities and spectral techniques, Indefinite-metric theories, Open quantum systems, Krein space methods, and Biorthogonal systems and applications. The book also provides a summary of recent advances in pseudo-Hermitian Hamiltonians and PT-symmetric Hamiltonians, as well as their applications in quantum physics and in the theory of open quantum systems.

"...useful for experts in mathematical physics...this is a very interesting book, which deserves to be found in any physical library." (OPTICS & PHOTONICS NEWS, July/August 2005).

El presente libro busca ser un apoyo para la asignatura Física I: Fundamentos de mecánica y termodinámica, que se imparte en el primer curso de ingeniería en la escuela politécnica de la Universidad Antonio de Nebrija. Los autores consideran que el texto es válido para el estudio de esta asignatura de primer curso, y que es transversal para los grados en Física, Química o cualquier ingeniería en otra escuela dentro del sistema actual de estudios universitarios

Este libro pretende facilitar herramientas matemáticas y modelos que se emplean en diversos campos (por ejemplo, coordenadas curvilíneas no ortogonales, concepto de tensor, fluido newtoniano) pero cuya dispersion en programas y bibliografia dificultan una vision de conjunto. Teniendo en cuenta que la termodinamica de no-equilibrio es una herramienta basica para el estudio de los sistemas continuos.

Este es un libro que abarca un amplio campo de la fisica pura y aplicada. En cada capitulo se establece en ofrma clara y concisa las definiciones, los principios y teoremas, los problemas tanto propuestos como resultos son expuestos en forma ordenada de menor a mayor grado de dificultad, y cumplen la funcion de revisar toda la teoria expuesta a traves de cada capitulo.

FORWARD ROBERT L.Desde que Albert Einstein, Paul Dirac, Carl Anderson, Emilio Segre y Owen Chamberlain, entre otros, descubrieron los secretos de la antimateria y de sus componentes, físicos de todo el mundo han comenzado a tratarla como una realidad. Han inventado complejas tecnicas para crear, almacenar y manipularla y se han enfrentado a los problemas de la aniquilacion materia-antimateria. Sin embargo, el verdadero uso de la antimateria sigue siendo ciencia ficcion. Los autores narran detalladamente la historia de este espectacular descubrimiento y describen los impresionantes medios tecnicos que lo hicieron posible. Explican cuales son todavia hoy las dificultades de los fisicos para manipular la antimateria y muestran las perspectivas futuras de su uso. Tal vez en vida de los lectores de este libro se podra lograr su fabricacion en cantidades suficientes para ser utilizada como "combustible" para propulsar naves espaciales en viajes interplanetarios.