Double well potentials and quantum gates

C. J. Foot, M. Shotter

Published 2009-02-25, updated 2011-03-22Version 2

The quantum system of particles in a double well potential is a widely studied and extremely useful example for understanding quantum mechanics. This simple system has recently been used in theoretical proposals and related experiments as a way to make quantum logic gates for ultra-cold atoms confined in optical lattices (periodic potentials arising from the interaction of atoms with standing waves of laser light). Such quantum gates are the fundamental building blocks for quantum information processing; in this context the regular array of cold atoms in the optical lattice serves as the quantum register. The purpose of this paper is to explain how this current research can be understood in terms of well-known principles for systems of identical particles, and hence furnish an up-to-date example for the teaching of quantum mechanics.