Optimal manipulations with qubits: Universal quantum entanglers
| Autoři | |
|---|---|
| Rok publikování | 2000 |
| Druh | Článek v odborném periodiku |
| Časopis / Zdroj | Physical Review A |
| Fakulta / Pracoviště MU | |
| Citace | |
| www | http://publish.aps.org/abstract/PRA/v62/e022303 |
| Obor | Teoretická fyzika |
| Klíčová slova | STATES; CLONING; SEPARABILITY; INFORMATION; ENSEMBLES |
| Popis | We analyze various scenarios for entangling two initially unentangled qubits. In particular, we propose an optimal universal entangler that entangles a qubit in unknown state \psi] with a qubit in a reference (known) state \0]. That is, our entangler generates the output state that is as close as possible to the pure (symmetrized) state (\psi]\0]+\0]\psi]). The most attractive feature of this entangling machine, is that the fidelity of its performance (i.e., the distance between the output and the ideally entangled-symmetrized state) does not depend on the input and takes the constant value F = (9 + 3 root 2)/14 similar or equal to 0.946. We also analyze how to optimally generate from a single qubit initially prepared in an unknown state \psi]) a two qubit entangled system, which is as close as possible to a Bell state (\psi]\psi(perpendicular to)]+\psi(perpendicular to)]\psi]), where [psi\psi(perpendicular to)] = 0. |
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