Published April 16, 2024 | Version v1
Journal article Open

Experimental Demonstration of Input-Output Indefiniteness in a Single Quantum Device

  • 1. CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, 230026, China
  • 2. CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, 230026, China
  • 3. Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China
  • 4. QICI Quantum Information and Computation Initiative, Department of Computer Science, The University of Hong Kong, Pokfulam Road, Hong Kong
  • 5. HKU-Oxford Joint Laboratory for Quantum Information and Computation
  • 6. Department of Computer Science, University of Oxford, Wolfson Building, Parks Road, Oxford, United Kingdom
  • 7. Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, Ontario, Canada

Description

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 tabletop simulations of hypothetical scenarios exhibiting quantum indefiniteness in the direction of time.

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10.1103_PhysRevLett.132.160201.pdf

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Additional details

Identifiers

DOI
10.1103/PhysRevLett.132.160201;
arXiv
arXiv:2210.17046;
Crossref Funder ID
10.13039/501100012166; 10.13039/501100001809; 10.13039/501100012226; 10.13039/501100009076; 10.13039/501100002858; 10.13039/100000925; 10.13039/501100012333;

Publishing Information

Journal Title
Physical Review Letters
Journal Volume
132
Journal Issue
16
Journal Page Range
7 pgs.
ISSN
0031-9007