# Elements of Quantum Theory

## Abstract

When we are dealing with relatively simple systems, in which we can measure distances and time intervals accurately, the ideas of force, potential and kinetic energies, and so on, are meaningful and useful terms to employ in describing phenomena. In many cases, however, e.g. in atomic systems, we cannot analyse the situation in quite the same way, because it is rather difficult to locate the particles and specify their velocities at a given time. We are then thrown back on to the “conservation” laws in order to find “observables” or “measureables”. The systems in which we shall be interested are those in which the total energy is conserved. When we write the total energy as the sum of the potential and kinetic energy functions, it is called the Hamiltonian of the system.

## Keywords

Angular Momentum Quantum Theory Dirac Equation Variational Theorem Potential Energy Versus## Preview

Unable to display preview. Download preview PDF.