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arXiv · 2002.10374

Carrying an arbitrarily large amount of information using a single quantum particle

Li-Yi Hsu·Ching-Yi Lai·You-Chia Chang·Chien-Ming Wu·Ray-Kuang Lee
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Abstract

Theoretically speaking, a photon can travel arbitrarily long before it enters into a detector, resulting a click. How much information can a photon carry? We study a bipartite asymmetric "two-way signaling" protocol as an extension of that proposed by Del Santo and Daki\'{c}. Suppose that Alice and Bob are distant from each other and each of them has an $n$-bit string. They are tasked to exchange the information of their local n-bit strings with each other, using only a single photon during the communication. It has been shown that the superposition of different spatial locations in a Mach-Zehnder (MZ) interferometer enables bipartite local encodings. We show that, after the travel of a photon through a cascade of $n$-level MZ interferometers in our protocol, the one of Alice or Bob whose detector clicks can access the other's full information of $n$-bit string, while the other can gain one-bit of information. That is, the wave-particle duality makes two-way signaling possible, and a single photon can carry arbitrarily large (but finite) information.

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Li-Yi Hsu, Ching-Yi Lai, You-Chia Chang, Chien-Ming Wu, Ray-Kuang Lee. 2020-02-24. Carrying an arbitrarily large amount of information using a single quantum particle. https://doi.org/10.1103/physreva.102.022620

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