Semi-device-independent certification of indefinite causal order in a photonic quantum switch

• URL: http://arxiv.org/abs/2202.05346v2
• Date: Wed, 3 May 2023 20:58:53 GMT
• Title: Semi-device-independent certification of indefinite causal order in a photonic quantum switch
• Authors: Huan Cao, Jessica Bavaresco, Ning-Ning Wang, Lee A. Rozema, Chao Zhang, Yun-Feng Huang, Bi-Heng Liu, Chuan-Feng Li, Guang-Can Guo, and Philip Walther
• Abstract summary: In a semi-device-independent scenario, indefinite causal order can be demonstrated with the quantum switch. We show that correlations generated in a photonic quantum switch, in which all parties are able to collect local outcome statistics, achieve a violation of this inequality of 224 standard deviations.
• Score: 4.058090592851957
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: We report an experimental certification of indefinite causal order that relies only on the characterization of the operations of a single party. We do so in the semi-device-independent scenario with the fewest possible assumptions of characterization of the parties' local operations in which indefinite causal order can be demonstrated with the quantum switch. To achieve this result, we introduce the concept of semi-device-independent causal inequalities and show that the correlations generated in a photonic quantum switch, in which all parties are able to collect local outcome statistics, achieve a violation of this inequality of 224 standard deviations. This result consists of the experimental demonstration of indefinite causal order with the fewest device-characterization assumptions to date.

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