2012/06/30 by Xiao‐Song Ma, Xiao-song Ma, Johannes Kofler +11 · 1 voice · 4 citations
Computer Science · Physics and Astronomy · #Computer science #Counterintuitive #Erasure #Interference (communication) #Photon #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum entanglement #Quantum information science #Quantum mechanics #Quantum pseudo-telepathy #Statistical physics #Telecommunications #Theoretical physics #physics.optics #quant-ph
paper · pdf · doi:10.1073/pnas.1213201110
published as Proc. Natl. Acad. Sci. USA 110, 1221-1226 (2013)
openalex publication_date 2013/01/03 · arxiv created 2013/01/29 · arxiv updated 2013/01/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The counterintuitive features of quantum physics challenge many common-sense assumptions. In an interferometric quantum eraser experiment, one can actively choose whether or not to erase which-path information (a particle feature) of one quantum system and thus observe its wave feature via interference or not by performing a suitable measurement on a distant quantum system entangled with it. In all experiments performed to date, this choice took place either in the past or, in some delayed-choice arrangements, in the future of the interference. Thus, in principle, physical communications between choice and interference were not excluded. Here, we report a quantum eraser experiment in which, by enforcing Einstein locality, no such communication is possible. This is achieved by independent active choices, which are space-like separated from the interference. Our setup employs hybrid path-polarization entangled photon pairs, which are distributed over an optical fiber link of 55 m in one experiment, or over a free-space link of 144 km in another. No naive realistic picture is compatible with our results because whether a quantum could be seen as showing particle- or wave-like behavior would depend on a causally disconnected choice. It is therefore suggestive to abandon such pictures altogether.