Abstract
We prove that for a programmable measurement device that approximates every POVM with an error , the dimension of the program space has to grow at least polynomially with . In the case of qubits we can improve the general result by showing a linear growth. This proves the optimality of the programmable measurement devices recently designed in G. M. D’Ariano and P. Perinotti, Phys. Rev. Lett. 94, 090401 (2005).
- Received 9 February 2006
DOI:https://doi.org/10.1103/PhysRevA.73.052315
©2006 American Physical Society