Universal and original-preserving quantum copying is impossible
نویسندگان
چکیده
منابع مشابه
(Nonrelativistic) Quantum Bit Commitment Really Is Impossible
Unconditionally secure (nonrelativistic) quantum bit commitment has been shown to be impossible by Mayers [23] and Lo and Chau [19, 20], but the claim is repeatedly challenged. The bit commitment theorem is reviewed here and the central conceptual point, that an ‘Einstein-Podolsky-Rosen’ attack or cheating strategy can always be applied, is clarified. The question of whether following such a ch...
متن کاملUnconditionally secure quantum bit commitment is impossible
The claim of quantum cryptography has always been that it can provide protocols that are unconditionally secure, that is, for which the security does not depend on any restriction on the time, space or technology available to the cheaters. We show that this claim does not hold for any quantum bit commitment protocol. Since many cryptographic tasks use bit commitment as a basic primitive, this r...
متن کاملHamiltonian for Quantum Copying
We derive an explicit Hamiltonian for copying the basis up and down states of a quantum two-state system—a qubit—onto n " copy " qubits (n ≥ 1) initially all prepared in the down state. In terms of spin components , for spin-1 2 particle spin states, the resulting Hamiltonian involves n-and (n + 1)-spin interactions. The case n = 1 also corresponds to a quantum-computing controlled-NOT gate.
متن کاملQuantum copying: A network
V. Bužek, S. L. Braunstein, M. Hillery, and D. Bruß 1 Optics Section, The Blackett Laboratory, Imperial College, London SW7 2BZ, United Kingdom 2 Institute of Physics, Slovak Academy of Sciences, Dubravská cesta 9, 842 28 Bratislava, Slovakia 3 University of Wales, Dean Street, Bangor LL57 1UT, United Kingdom 4 Department of Physics and Astronomy, Hunter College, CUNY, 695 Park Avenue, New York...
متن کاملA Hamiltonian for Quantum Copying
We derive an explicit Hamiltonian for copying the basis up and down states of a quantum two-state system—a qubit—onto n " copy " qubits (n ≥ 1) initially all prepared in the down state. In terms of spin components , for spin-1 2 particle spin states, the resulting Hamiltonian involves n-and (n + 1)-spin interactions. The case n = 1 also corresponds to a quantum-computing controlled-NOT gate.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Physics Letters A
سال: 2002
ISSN: 0375-9601
DOI: 10.1016/s0375-9601(02)00388-2