Discrimination of the Bell states of qudits by means of linear optics

OPTICS COMMUNICATIONS

卷:199

Article

Dusek, M

关键词: qudit;    bell state;    quantum computation;    linear optics;    Bell measurement;    quantum information;   

DOI  :  10.1016/S0030-4018(01)01565-6

来源: Elsevier

【 摘 要 】

The question of the discrimination of the Bell states of two qudits (i.e., d-dimensional quantum systems) by means of passive linear optical elements and conditional measurements is discussed. A qudit is supposed to be represented by d optical modes containing exactly one photon altogether. From recent results of Calsamiglia it follows that there is no way how to distinguish the Bell states of two qudits for d > 2-not even with the probability of success lower than one-without any auxiliary photons in ancillary modes. Following the results of Carollo and Palma it is proved that it is impossible to distinguish even only one such Bell state with certainty (i.e., with the probability of success equal to one), irrespective of how many auxiliary photons are involved. However, it is shown that auxiliary photons can help to discriminate the Bell states of qudits with the high probability of success: A Bell-state analyzer based on the idea of linear optics quantum computation that can achieve the probability of success arbitrarily close to one is described. It requires many auxiliary photons that must be first combined into entangled states. (C) 2001 Published by Elsevier Science B.V.

【 授权许可】

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