Libros de Física, página 44 de 362

Life is an enduring mystery. Yet, science tells us that living beings are merely sophisticated structures of lifeless molecules. If this view is correct, where do the seemingly purposeful motions of cells and organisms originate? In Life's Ratchet, physicist Peter M. Hoffmann locates the answer to this age-old question at the nanoscale. Below the calm, ordered exterior of a living organism lies microscopic chaos, or what Hoffmann calls the molecular storm--specialized molecules immersed in a whirlwind of colliding water molecules. Our cells are filled with molecular machines, which, like tiny ratchets, transform random motion into ordered activity, and create the "purpose" that is the hallmark of life. Tiny electrical motors turn electrical voltage into motion, nanoscale factories custom-build other molecular machines, and mechanical machines twist, untwist, separate and package strands of DNA. The cell is like a city--an unfathomable, complex collection of molecular workers working together to create something greater than themselves. Life, Hoffman argues, emerges from the random motions of atoms filtered through these sophisticated structures of our evolved machinery. We are agglomerations of interacting nanoscale machines more amazing than anything in science fiction. Rather than relying on some mysterious "life force" to drive them--as people believed for centuries--life's ratchets harness instead the second law of thermodynamics and the disorder of the molecular storm. Grounded in Hoffmann's own cutting-edge research, Life's Ratchet reveals the incredible findings of modern nanotechnology to tell the story of how the noisy world of atoms gives rise to life itself.

What astronomers know about our universe changes every day. For the past twenty years, Universe has been the most thrilling way to communicate the excitement of discovery in astronomy to students of all scientific backgrounds. The new edition of Universe gives students the means to explore like never before. In addition to covering all the top discoveries, the text contains spectacular images, captivating writing, and a media and supplements package that guides students on a fascinating journey around the cosmos and back again.

Our understanding of galaxies has advanced significantly in recent years. New observations from ground- and space-based telescopes, the discovery of dark matter, and powerful computer simulations have been instrumental in this. This textbook provides graduate students with a complete and thorough introduction to galactic dynamics. The first two parts of the book define the astrophysical problems and the methods for building sound physical models. Next, the observational properties and models of spiral then elliptical galaxies are examined in detail. Finally, a selection of exciting topics from contemporary research are introduced, including the formation and evolution of galaxies, cooling flows, accretion disks, and galaxies at high redshift. Throughout, the emphasis is on developing a clear understanding and good physical intuition of the processes involved. Full derivations are provided for key results and helpful problems are included. This textbook provides graduate students with a self-contained and accessible introduction to modern galactic dynamics.

This is an introduction to Lie algebras and their applications in physics. The first three chapters show how Lie algebras arise naturally from symmetries of physical systems and illustrate through examples much of their general structure. Chapters 4 to 13 give a detailed introduction to Lie algebras and their representations, covering the Cartan-Weyl basis, simple and affine Lie algebras, real forms and Lie groups, the Weyl group, automorphisms, loop algebras and highest weight representations. Chapters 14 to 22 cover specific further topics, such as Verma modules, Casimirs, tensor products and Clebsch-Gordan coefficients, invariant tensors, subalgebras and branching rules, Young tableaux, spinors, Clifford algebras and supersymmetry, representations on function spaces, and Hopf algebras and representation rings. A detailed reference list is provided, and many exercises and examples throughout the book illustrate the use of Lie algebras in real physical problems. The text is written at a level accessible to graduate students, but will also provide a comprehensive reference for researchers.

La Mecánica clásica actual está lejos de ser un tema cerrado. Las tres últimas decadas han visto la floración de nuevos desarrollos en Mecánica clásica, el abordaje de nuevos problemas y la aplicación de las tecnicas de la Mecanica clasica a cuestiones de largo alcance de la Fisica y la Quimica.Repaso de los principios elementales. Principios variacionales y ecuaciones de Lagrange. Problemas de los dos cuerpos. Cinematica del cuerpo rigido. Ecuaciones de movimiento del cuerpo rigido. Oscilaciones pequeñas. Relatividad especial en Mecanica clasica.

Este libro explica los principios fundamentales de la Física en el contexto de la Tecnología moderna. Se ha escrito para una amplia clase de estudiantes de orientación técnica (Arquitectos, Ingenieros, Maestros industriales, etc.) que necesitan un conocimiento general de la Física y de su relación con su tarea. A lo largo de todo el libro se utilizan aplicaciones reales de la Física a la Ciencia y a la Industria, tanto para aclarar los principios físicos como para explicar aspectos importantes de la Tecnología moderna.

La Física Cuántica es la física de nuestro siglo. Su contenido es hoy imprescindible no sólo para el físico, sino también para otros profesionales (químicos, ingenieros, médicos…).El libro ha sido re