Quantum cloning machines for equatorial qubits
نویسندگان
چکیده
Quantum cloning machines for equatorial qubits are studied. For 1 to 2 phase-covariant quantum cloning machine, using Hilbert-Schmidt norm and Bures fidelity, we show that our transformation can achieve the bound of the fidelity. Networks consisting of quantum gates are presented to realize the quantum cloning transformations. The copied equatorial qubits are shown to be separable by using Peres-Horodecki criterion. The optimal 1 to M phase-covariant quantum cloning transformations are given. PACS: 03.67.-a, 03.65.Bz, 89.70.+c.
منابع مشابه
Optimal quantum cloning networks for equatorial qubits
Considering the optimal quantum cloning transformations for equatorial qubits, the quantum cloning networks for equatorial qubits consisting of quantum gates are presented. The copied equatorial qubits are separable by using Peres-Horodecki criterion. The phase-covariant optimal quantum triplicators are given. PACS: 03.67.-a, 03.65.Bz, 89.70.+c.
متن کاملThe Coordinate Ratios as a Tool to Analyze the Intrusion Based on Bužek-hillery Quantum Copying Machine
The intrusion based on Bužek-Hillery universal quantum copying machine (UQCM) is investigated. A major problem to the eavesdropper Eve is how to choose the intrusion parameters required by the copying machine in order to take out the maximum of information on the transmitted qubits while making her intrusion as discrete as possible. The present paper attempts to investigate the equatorial and i...
متن کاملRealization of the 1 → 3 optimal phase - covariant quantum cloning machine
The 1 → 3 quantum phase covariant cloning, which optimally clones qubits belonging to the equatorial plane of the Bloch sphere, achieves the fidelity F1→3 cov = 0.833, larger than for the 1 → 3 universal cloning F1→3 univ = 0.778. We show how the 1 → 3 phase covariant cloning can be implemented by a smart modification of the standard universal quantum machine by a projection of the output state...
متن کاملSeparability in asymmetric phase-covariant cloning
Here, asymmetric phase-covariant quantum cloning machines are defined and trade-off between qualities of their outputs and its impact on entanglement properties of the outputs are studies. In addition, optimal families among these cloners are introduced and also their entanglement properties are investigated. An explicit proof of optimality is presented for the case of qubits, which is based on...
متن کاملOptimal Cloning and No Signaling
It is shown that no signaling constraint generates the whole class of 1 → 2 optimal quantum cloning machines of single qubits
متن کامل