1302.0932 (S. J. van Enk et al.)

When quantum tomography goes wrong: drift of quantum sources and other
errors    [PDF]

S. J. van Enk, Robin Blume-Kohout

The principle behind quantum tomography is that a large set of observations -- many samples from a "quorum" of distinct observables -- can all be explained satisfactorily as measurements on a single underlying quantum state or process. Unfortunately, this principle may not hold. When it fails, any standard tomographic estimate should be viewed skeptically. Here we propose a simple way to test for this kind of failure using Akaike's Information Criterion (AIC). We point out that the application of this criterion in a quantum context, while still powerful, is not as straightforward as it is in classical physics. This is especially the case when future observables differ from those constituting the quorum.

View original: http://arxiv.org/abs/1302.0932