Appendix D

Electromagnetic Forces at the Quantum Level

In 1900, Max Planck presented a theory on the quantization of energy levels of thermal radiation and this is considered the birth of quantum physics. In 1905, Albert Einstein postulated that all energy is quantized, including light and electromagnetism. The photon, the quanta of electromagnetic energy, can be considered to have characteristics that are like a localized particle, and characteristics that are like a wave. Quantum physics stipulates that any energy must consist of individual packets, or quanta, and that stipulation can be described quite clearly when the field is in motion and energy is changing. The statement implies, however, that even static (unchanging) electromagnetic fields must consist of particles. These particles are called virtual photons.

The core concept behind energy quanta is the idea that all electromagnetic energy is transferred in integer quantities of a fundamental unit. This unit is called Planckʼs constant and itʼs represented by the letter h. Another principle of quantum physics is the Heisenberg uncertainty principle. It states that you can never know both the exact position and momentum of any particle and bounds the errors in determining both in the expression ∆p∆x ≥ h/4π where ∆p is the momentum and ∆x is the position. The uncertainty principle is not a limit set by the accuracy of measuring equipment. It is a fundamental property of nature.

The uncertainty principle can also be used to conclude that particles of small enough energy and short enough life spans can exist, but you can never measure them. This idea can be stated by the expression ∆E∆t ≤ h/4π where ∆E is the energy and ∆t is the life time. This expression allows for virtual photons which can spontaneously appear and disappear as long as they obey both the uncertainty principle and the law of conservation of energy.

The stored energy in the near field of an electromagnetic radiator allows the creation of virtual photons. They carry the electromagnetic force in the non-radiating portion of the field. The virtual photons have all the properties of real photons that make up the radiating fields except that they exist for a very short time and they cease to exist if their source is no longer present.

Copyright 2003 - Joseph Bardwell