Regular Article – Quantum Optics
Visualizing multiqubit correlations using the Wigner function
Tokyo Institute of Technology, 2-12-1 Ookayama, 152-8550, Meguro-ku, Tokyo, Japan
2 Department of Physics and Quantum Systems Engineering Research Group, Loughborough University, LE11 3TU, Leicestershire, United Kingdom
3 Faculty of Physics, Vienna Center for Quantum Science and Technology (VCQ), University of Vienna, Boltzmanngasse 5, A-1090, Vienna, Austria
4 Dipartimento di Fisica, Sapienza Università di Roma, P.le Aldo Moro 5, 00185, Rome, Italy
5 NTT Basic Research Labs & NTT Research Center for Theoretical Quantum Physics, NTT Corporation, 3-1 Morinosato-Wakamiya, 243-0198, Atsugi, Kanagawa, Japan
6 National Institute of Informatics, 2-1-2 Hitotsubashi, 101-8430, Chiyoda-ku, Tokyo, Japan
7 Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, 00146, Rome, Italy
Accepted: 8 May 2022
Published online: 20 May 2022
Quantum engineering now allows to design and construct multi-qubit states in a range of physical systems. These states are typically quite complex in nature, with disparate, but relevant properties that include both single and multi-qubit coherences and even entanglement. All these properties can be assessed by reconstructing the density matrix of those states—but the large parameter space can mean physical insight of the nature of those states and their coherence can be hard to achieve. Here, we explore how the Wigner function of a multipartite system and its visualization provides rich information on the nature of the state, not only at illustrative level but also at the quantitative level. We test our tools in a photonic architecture making use of the multiple degrees of freedom of two photons.
© The Author(s) 2022. corrected publication 2022
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