1112.3642 (Won-Young Hwang)

How to Device-Independently Generate States for Which Unambiguous State
Discrimination is Impossible    [PDF]

Won-Young Hwang

We describe how to device-independently generate a set of quantum states for which unambiguous state discrimination is not possible. First we derive a formula that a certain non-signaling black-box must satisfy. Then we describe how to generate a set of quantum states. Devices for generating states and possible measurement on the states can be put into a black-box. Because this black-box is non-signaling, it satisfies the formula. Using the formula, we prove that USD is not possible for the generated states. Because we did not consider internal mechanism but only outcomes, our argument is valid for any (imperfect) devices.

View original: http://arxiv.org/abs/1112.3642