Gauge invariance and time symmetry breaking
Employing an arbitrary velocity gauge transformation this contribution argues that the breaking of time symmetry is a natural consequence of irreversibility.
physics.gen-ph↗
arXiv subjects
R Assumpcao
Publications and source records attributed to R Assumpcao.
Time and Entropy in the Foundations of Mechanics
This contribution analyses the classical laws of motion by means of an approach relating time and entropy. We argue that adopting the notion of change of states as opposed to the usual derivation of Newton's laws in terms of fields a broader picture is obtained, suggesting that diverse branches of physics- classical, quantum, relativistic and statistical mechanics - turn out to be related by a common foundation.
physics.gen-ph↗
Relativity in Classical Mechanics: Momentum, Energy and the Third Law
Most of the logical objections against the classical laws of motion, as they are usually presented in textbooks, centre on the fact that defining force in terms of mass and acceleration, the first two laws are mere assertions of concepts to be introduced in the theory; conversely, the third law expresses the experimental fact that the ratio of masses is inversely proportional to the ratio of accelerations, but it is known to fail when the interacting bodies are rapidly accelerated or far apart, leading to objections at the research level, particularly when electromagnetic phenomena is present. Following a specification of the coordinate system with respect to which velocities and accelerations are to be measured, relative to a fixed spacetime point, this contribution argues that the limitation of the third law is removed; as a consequence, Energy and Momentum relations are given an alternative formulation, extending their fundamental aspects and terms to the relativistic level. Most important, the presented alternative relations seem to preserve exactly the same form of the concepts as originally used by Newton in the Principia.
physics.gen-ph↗
One more experiment on "fast-light"
Contemporary observational and theoretical studies on the temporal nature of microscopic measurements renewed the discussion about the fundamental constants, leading to the possibility of light speed variation and superluminal pulse propagation. Gain assisted experiments using anomalous dispersion near an absorption line in atomic gas, a "fast - light" medium, seem to lead to a wave group velocity vG exceeding c, the vacuum speed of light; moreover, definition of the information velocity vi sets the question of interpretation of the three speeds: one view is that vi = vG, but this violates Causality; another view is that vi = c in all situations, but this limits, a priori, the transport of information. Another view is that vi, vG and c are distinct. This contribution follows the last possibility. A draft discussion on space-time is given.
physics.gen-ph↗