Classical Physics

David Hodgson

By the end of the nineteenth century, tremendous advances had been made in the understanding of the physical world; and classical physics as developed up to that time provided powerful and coherent models for a wide range of phenomena. In order to suggest the range and power of classical physics, this chapter starts by reviewing briefly some areas of classical physics, and pointing out certain assumptions about the world and about measurement which underlie and are reflected in classical physics. It then outlines, as an extension of classical physics and as part of pre-quantum physics, aspects of the theory of relativity. The remainder of the chapter explains why the reasonable and common-sense views of classical physics had to be discarded; and gives some understanding of the historical development of quantum physics and of the refutations of common-sense views involved.

A. O. Bolivar

R. Asokamani

Gary E. Bowman

This introductory chapter outlines the differences between classical physics and quantum physics by positing three imaginary worlds. World 1 is governed by the laws of classical Newtonian mechanics, World 2 by classical field physics, and World 3 by quantum physics. The point is that classical physics deals with well-defined, continuously-existing physical quantities, including trajectories, while quantum physics is fundamentally about physical quantities defined in terms of probability functions.

Marmo, G, David Martı́n de Diego, Lecanda, Miguel

Yao Shen, Liang Hao, Gui‐Lu Long

It is pointed out that the noncloning theorem in quantum mechanics also holds for unknown state in linear classical physics. The apparent capability of copying of a classical state is essentially the capability of perfect measurement in classical physics. The difference in copying between quantum and classical physics is the difference in measurement between the two theories. A classical copying process is the combined action of measurement of an unknown state and the preparation of this state onto another system. Hence perfect measurability in classical physics enables the copying of a classical state.