15
Bits and pieces
15.1 Casimir eect - forces from nothing
For many quantum systems, such as the harmonic oscillator, there is still some energy associated
with the lowest quantum state. This zero-point energy is real, and can be measured in the
Casimir e

12
12.1
Scattering in three dimensions
Cross sections and geometry
Most experiments in physics consist of sending one particle to collide with another, and looking
at what comes out.
The quantity we can usually measure is the scattering cross section: by

11
11.1
Fundamentals of Quantum Scattering Theory
Centre of Mass Frame and the Two-body Problem
The problem of a particle in a given potential can be solved classically from Newtons equations.
The Schroedinger equation can be used to describe the behaviou

13
13.1
Further Concepts in Quantum Scattering Theory
Born Series, Green Functions - A Hint of Quantisation of the Field
Solving the Schroedinger equation using Green Functions automatically gives a solution in a form
appropriate for scattering. By making