# Quantized Field Effects

## Document Type

Article

## Publication Date

1-1-2006

## Abstract

quantized field effects The electromagnetic field appears almost everywhere in physics. Following the introduction of Maxwell's equations in 1864, Max Planck initiated quantum theory when he discovered h = 2πℏ in the laws of black-body radiation. In 1905 Albert Einstein explained the photoelectric effect on the hypothesis of a corpuscular nature of radiation and in 1917 this paradigm led to a description of the interaction between atoms and electromagnetic radiation. The study of quantized field effects requires an understanding of the quantization of the field which leads to the concept of a quantum of radiation, the photon. Specific nonclassical features arise when the field is prepared in particular quantum states, such as squeezed states. When the radiation field interacts with an atom, there is an important difference between a classical field and a quantized field. A classical field can have zero amplitude, in which case it does not interact with the atom. On the other hand a quantized field always interacts with the atom, even if all the field modes are in their ground states, due to vacuum fluctuations. These lead to various effects such as spontaneous emission and the Lamb shift. The interaction of an atom with the many modes of the radiation field can conveniently be described in an approximate manner by a master equation where the radiation field is treated as a reservoir. Such a treatment gives a microscopic and quantum mechanically consistent description of damping.

## Publication Source (Journal or Book title)

Springer Handbooks

## First Page

1141

## Last Page

1165

## Recommended Citation

Freyberger, M., Vogel, K., Schleich, W., & O'Connell, R.
(2006). Quantized Field Effects.* Springer Handbooks*, 1141-1165.
https://doi.org/10.1007/978-0-387-26308-3_78