Controlling wave-particle duality with entanglement between single-photon and Bell states

Kai Wang, Daniel R. Terno, Časlav Brukner, Shining Zhu, Xiao Song Ma (Corresponding author)

Publications: Contribution to journalArticlePeer Reviewed


Wave-particle duality and entanglement are two fundamental characteristics of quantum mechanics. All previous works on experimental investigations in wave-particle properties of single photons (or single particles in general) showed that a well-defined interferometer setting determines a well-defined property of single photons. Here we take a conceptual step forward and control the wave-particle property of single photons with a Bell state. By doing so, we experimentally test the complementarity principle in a scenario in which the setting of the interferometer is not defined at any instance of the experiment, not even in principle. To achieve this goal, we establish the three-photon entangled state, i.e., the entanglement between a single photon and a two-photon Bell state, send the photon of interest S into a quantum Mach-Zehnder interferometer (MZI), in which the output beam splitter of the MZI is controlled by the quantum state of the second photon C, which is entangled with a third photon A. Therefore, the individual quantum state of photon C is undefined, which implements the undefined settings of the MZI for photon S. This is realized by using three cascaded phase-stable interferometers for three photons. There is typically no well-defined setting of the MZI and thus the very formulation of the wave-particle objectivity from local hidden variable models becomes internally inconsistent.
Original languageEnglish
Article number053715
Number of pages10
JournalPhysical Review A
Issue number5
Publication statusPublished - Nov 2022

Austrian Fields of Science 2012

  • 103026 Quantum optics
  • 103025 Quantum mechanics

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