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

Kai Wang, Daniel R. Terno, Časlav Brukner, Shining Zhu, Xiao Song Ma

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.

Quantum Optics, Quantum Nanophysics and Quantum Information
External organisation(s)
Nanjing University, Macquarie University, Southern University of Science and Technology, Österreichische Akademie der Wissenschaften (ÖAW), University of Science and Technology of China (USTC)
Physical Review A
No. of pages
Publication date
Peer reviewed
Austrian Fields of Science 2012
103026 Quantum optics, 103025 Quantum mechanics
ASJC Scopus subject areas
Atomic and Molecular Physics, and Optics
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