Artículos con la etiqueta ‘Física y Filosofía’

Schwinger’s Quantum Action Principle. I. From Dirac’s Formulation through Feynman’s Path Integrals to the Schwinger-Keldysh Method

Por • 23 feb, 2014 • Category: Leyes

Starting from the earlier notions of stationary action principles, we show how Schwinger’s Quantum Action Principle descended from Dirac’s formulation, which independently led Feynman to his path-integral formulation of quantum mechanics. The connection between the two is brought out, and applications are discussed. The Keldysh-Schwinger time-cycle method of extracting matrix elements is described. Part II will discuss the variational formulation of quantum electrodynamics and the development of source theory.

Why Do We See a Classical World?

Por • 6 ene, 2012 • Category: Filosofía

From a general abstract system theoretical perspective, a quantum-like system description in the spirit of a generalized quantum theory may appear to be simpler and more natural than a classically inspired description. We investigate the reasons why we nevertheless conceive ourselves embedded into a classically structured world

The Riddle of Gravitation

Por • 9 dic, 2011 • Category: Opinion

There is no doubt that both the special and general theories of relativity capture the imagination. The anti-intuitive properties of the special theory of relativity and its deep philosophical implications, the bizzare and dazzling predictions of the general theory of relativity: the curvature of spacetime, the exotic characteristics of black holes, the bewildering prospects of gravitational waves, the discovery of astronomical objects as quasers and pulsers, the expansion and the (possible) recontraction of the universe…, are all breathtaking phenomena. In this paper, we give a philosophical non-technical treatment of both the special and the general theory of relativity together with an exposition of some of the latest physical theories. We then give an outline of an axiomatic approach to relativity theories due to Andreka and Nemeti that throws light on the logical structure of both theories. This is followed by an exposition of some of the bewildering results established by Andreka and Nemeti concerning the foundations of mathematics using the notion of relativistic computers. We next give a survey on the meaning and philosophical implications of the the quantum theory and end the paper by an imaginary debate between Einstein and Neils Bohr reflecting both Einstein’s and Bohr’s philosophical views on the quantum world.