Repozytorium publikacji - Politechnika Gdańska

It is one of fundamental features of quantum formalism that o n one hand it provides a new infor- mation processing resources and on the other hand puts funda mental constraints on the processing of quantum information implying “no-go” theorems for cloni ng [1–3], bit commitment [4, 5] and deleting [6] in quantum theory. Here we ask about possibilit y of “zero knowledge” scenario which, for its simplicity, can be considered as a quantum primitive or model scenario for any problems of similar kind. Consider two parties: Alice and Bob and suppos e that Bob is given a qubit system in a quantum state φ , unknown to him. Alice knows φ and she is supposed to convince Bob that she knows φ sending some test message. Is it possible for her to convince Bob providing him ”zero knowledge” i. e. no information about φ he has? We prove that there is no ”zero knowledge” protocol of that kind. In fact it turns out that basing on Alic e message, Bob (or third party - Eve - who can intercept the message) can synthetize a copy of t he unknown qubit state φ with nonzero probability. This ”no-go” result puts general cons trains on information processing where information about quantum state is involved.

Autorzy

• prof. dr hab. Paweł Horodecki link otwiera się w nowej karcie ,
• Ryszard Horodecki,
• Michał Horodecki link otwiera się w nowej karcie