Room 117

Quantum Theory Contains Maximally Incompatible Observables

Sibasish Ghosh

IMSc

I will talk about the following paper of P. Busch, T. Heinosaari, and J. Schultz, arXiv:1210.4142 [quant-ph].

Abstract: In any no-signalling probabilistic theory (PT), the joint measurability region D(A, B) of any pair of observables (A, B) is defined to be the collection of all pairs (a, b) in [0, 1] X [0, 1] such that noisy pair (aA + (1 - a)T_1, bB + (1 - b)T_2) becomes jointly measurable for trivial observables T_1 and T_2. The joint measurability region D_{PT} for any given PT is the common portion among all D(A, B)'s. The present paper showed that the joint measuarability region D_{QM} is always contained in D_{PT} for all PT. I will also try to compare this result with a result of Wolf et al. [Phys. Rev. Lett., vol. 103, 230402 (2009)] on the issue of incompatibility of pair of observables.