Biomedical subjects

Antoni Wójcik

Publications and source records attributed to Antoni Wójcik.

2 recordsLinked to original sources

PubMed2004

Quasiperiodic dynamics of a quantum walk on the line.

We study the dynamics of a generalization of a quantum coin walk on the line, which is a natural model for a diffusion modified by quantum or interference effects. In particular, our results provide surprisingly simple explanations for recurrence phenomena observed by Bouwmeester et al. [Phys. Rev. A 61, 13410 (1999)]] in their optical Galton board experiment, and a description of a stroboscopic quantum walk given by Buerschaper and Burnett [quant-ph/0406039] through numerical simulations. We also provide heuristic explanations for the behavior of our model which show, in particular, that its dynamics can be viewed as a discrete version of Bloch oscillations.

Journal Article↗

PubMed2003

Eavesdropping on the "ping-pong" quantum communication protocol.

Security of the "ping-pong" quantum communication protocol recently proposed by Boström and Felbinger [Phys. Rev. Lett. 89, 187902 (2002)]] is analyzed in the case of considerable quantum channel losses. The eavesdropping scheme is presented, which reveals that the ping-pong protocol is not secure for transmission efficiencies lower than 60%. Our scheme induces 50% losses, which, however, can be hidden in the channel losses if one replaces the original lossy channel with a less lossy one. Finally, a possible improvement of the ping-pong protocol security is proposed.

Journal Article↗