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arXiv · 1812.00624

From classical to quantum walk via erasure of which-way information

Mikolaj Lewandowski·Tomasz Kopyciuk·Pawel Kurzynski
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Abstract

Decoherence transforms a ballistic quantum walk into a diffusive classical random walk. After each step the environment measures the particle's path and the outside world gets to know the which-way information. The relation between the which-way information and the classicality of the spatial distribution is clearly visible in the multi-coin quantum walk in which the information about particle's path is encoded in the multi-coin degree of freedom. The more information is stored on the coins, the more classical and diffusive the spatial distribution is. Here, we propose a generalized version of the quantum eraser scenario that allows for complex erasure strategies. We show that the which-way information can be erased from the coins and the ballistic features in the spatial probability distribution can be recovered.

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Mikolaj Lewandowski, Tomasz Kopyciuk, Pawel Kurzynski. 2018-12-03. From classical to quantum walk via erasure of which-way information. https://arxiv.org/abs/1812.00624

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