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arXiv · 2210.17046

Experimental demonstration of input-output indefiniteness in a single quantum device

Yu Guo·Zixuan Liu·Hao Tang·Xiao-Min Hu·Bi-Heng Liu·Yun-Feng Huang·Chuan-Feng Li·Guang-Can Guo·Giulio Chiribella
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Abstract

Quantum theory allows information to flow through a single device in a coherent superposition of two opposite directions, resulting into situations where the input-output direction is indefinite. Here we introduce a theoretical method to witness input-output indefiniteness in a single quantum device, and we experimentally demonstrate it by constructing a photonic setup that exhibits input-output indefiniteness with a statistical significance exceeding 69 standard deviations. Our results provide a way to characterize input-output indefiniteness as a resource for quantum information and photonic quantum technologies and enable table-top simulations of hypothetical scenarios exhibiting quantum indefiniteness in the direction of time.

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Yu Guo, Zixuan Liu, Hao Tang, Xiao-Min Hu, Bi-Heng Liu, Yun-Feng Huang, Chuan-Feng Li, Guang-Can Guo, Giulio Chiribella. 2022-10-31. Experimental demonstration of input-output indefiniteness in a single quantum device. https://doi.org/10.1103/physrevlett.132.160201

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