Quantum cryptography Page 1 Quantum cryptography Nicolas Gisin, Grégoire Ribordy,
Wolfgang Tittel, and Hugo Zbinden Group of Applied Physics, University of Geneva, 1211 …

The impossibility of perfectly copying (or cloning) an unknown quantum state is one of the
basic rules governing the physics of quantum systems. The processes that perform the …

A strong converse theorem for the classical capacity of a quantum channel states that the
probability of correctly decoding a classical message converges exponentially fast to zero in …

Although perfect copying of unknown quantum systems is forbidden by the laws of quantum
mechanics, approximate cloning is possible. A natural way of realizing quantum cloning of …

Entangled photon pairs—discrete light quanta that exhibit non-classical correlations—play a
crucial role in quantum information science (for example, in demonstrations of quantum non …

We observe polarization entanglement between four photons produced from a single down-
<? format?> conversion source. The nonclassical correlations between the measurement …

No-cloning theorem is fundamental for quantum mechanics and for quantum information
science that states an unknown quantum state cannot be cloned perfectly. However, we can …

In classical computation, a 'bit'of information can be flipped (that is, changed in value from
zero to one and vice versa) using a logical NOT gate; but the quantum analogue of this …

We demonstrate genuine multipartite quantum entanglement of four photons in their orbital
angular momentum degrees of freedom, where a high-dimensional discrete Hilbert space is …

A transformation achieving the optimal symmetric N→ M cloning of coherent states is
presented. Its implementation requires only a phase-insensitive linear amplifier and a …