Experiments to Control Atom Number and Phase-Space Density in ...

Chapter 1
Introduction
Atomic physics is the study of the atomic energy level structure and of atomic
interactions with other particles, external magnetic fields, and external electric fields.
It has also been a testing ground for theories of quantum mechanics. As such, it is a
research field with a long tradition.
One could argue that modern atomic physics started with J.J. Thomson’s dis-
covery of the electron [1]. Ernest Rutherford, and the discovery of atomic structure
consisting of a nucleus surrounded by a cloud of orbiting electrons, was the next step
only a few years later [2]. Max Planck’s postulate of energy quantization of oscillators
in a black body, and Niels Bohr’s model of the atomic nucleus surrounded by electrons
moving in circular orbits were the first attempts to explain quantum phenoma such as
the spectral emission lines of hydrogen in terms of the underlying atomic structure [3, 4].
In the following years of the early 20th century many exciting discoveries were made and
theories developed, including work by Einstein and deBroglie, ultimately leading to the
development of quantum mechanics by Heisenberg, Schrödinger and others.
Even though much progress in the understanding of atomic structure was made
during the mid 20th century, the experimental techniques used in this dissertation were
not developed until the 1980s, when William Phillips, Harold Metcalf and co-workers
developed the Zeeman slower to reduce the velocity of an effusive atomic beam [5–7].
Following this development was the experimental realization of optical molasses and
magneto-optical trapping in 1987 [8], work for which Steven Chu was awarded the nobel
prize in 1997, together with Claude Cohen-Tannoudji and William Phillips. These are
still the standard techniques used today to cool and trap neutral atoms, and they have
led to the realization of Bose-Einstein condensates [9–11] and degenerate Fermi gases
[12–14].
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