Feynman's Integral is About Mutually Unbiased Bases
arXiv:0708.3079
Abstract
The Feynman integral can be seen as an attempt to relate, under certain circumstances, the quantum-information-theoretic separateness of mutually unbiased bases to causal proximity of the measuring processes.
v3: fixed typos v2: two reference added, fixed some typos and one obvious error, 12 pages