How far apart are classical and quantum systems?
arXiv:quant-ph/0308049
Abstract
As is well known, classical systems approximate quantum ones -- but how well? We introduce a definition of a "distance" on classical and quantum phase spaces that offers a measure of their separation. Such a distance scale provides a means to measure the quality of approximate solutions to various problems. A few simple applications are discussed.
LaTeX, 10 pages, no figures