On coexistence and joint measurability of rank-1 quantum observables

: Juha-Pekka Pellonpää

Publisher: IOP PUBLISHING LTD

: 2014

: Journal of Physics A: Mathematical and Theoretical

: JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL

: J PHYS A-MATH THEOR

: 052002

: 47

: 5

: 12

: 1751-8113

DOI: https://doi.org/10.1088/1751-8113/47/5/052002

We show that a rank-1 quantum observable (POVM) M is jointly measurable with a quantum observable M' exactly when M' is a smearing of M. If M is extreme, rank-1 and discrete, then M and M' are coexistent if and only if they are jointly measurable.