Distribuição Quântica de Chaves em Canais Quânticos com Decaimento Coletivo de Amplitude


One of the most mature quantum information tech- niques nowadays is quantum key distribution (QKD) in which two legitimate parties make use of a protocol to create a symme- tric private key using a quantum channel. The quantum channel is not secure, since there may be an eavesdropper intercepting and re-sending the quantum states that are sent through it. One of the main problems in using QKD protocols is the existence of noise which can difficult the task of eavesdropping checking. Considering these issues, this paper presents a QKD protocol over a collective amplitude damping quantum channel that makes use of decoherence-free subspaces and subsystems. The QKD protocol proposed is noiseless despite the errors existing in the quantum channel and its use results in an asymptotically negligible probability of the eavesdropper retrieve the secret key. Besides, the probability of eavesdropper detection is stable during the whole communication which eases the eavesdropping checking procedures.

In: Workshop-Escola de Computação e Informação Quânticas, WECIQ 2015. Campina Grande, Paraíba.