Minimal Informationally Complete Measurements for Pure States
Abstract
We consider measurements, described by a positive-operator-valued measure (POVM), whose outcome probabilities determine an arbitrary pure state of a D-dimensional quantum system. We call such a measurement a pure-state informationally complete (PSI-complete) POVM. We show that a measurement with 2D-1 outcomes cannot be PSI-complete, and then we construct a POVM with 2D outcomes that suffices, thus showing that a minimal PSI-complete POVM has 2D outcomes. We also consider PSI-complete POVMs that have only rank-one POVM elements and construct an example with 3D-2 outcomes, which is a generalization of the tetrahedral measurement for a qubit. The question of the minimal number of elements in a rank-one PSI-complete POVM is left open.
Keywords
Cite
@article{arxiv.quant-ph/0404137,
title = {Minimal Informationally Complete Measurements for Pure States},
author = {Steven T. Flammia and Andrew Silberfarb and Carlton M. Caves},
journal= {arXiv preprint arXiv:quant-ph/0404137},
year = {2009}
}
Comments
2 figures, submitted for the Asher Peres festschrift