Abstract
Intraparticle entanglement of individual particles such as neutrons could enable another class of scattering probes that are sensitive to entanglement in quantum systems and materials. In this work, we present experimental results demonstrating quantum contextuality as a result of entanglement between the spin and energy modes (i.e., degrees of freedom) of single neutrons in a beam using a pair of resonant radio-frequency neutron spin flippers in the modulated intensity with zero effort configuration. We verified the mode entanglement by measuring a Clauser-Horne-Shimony-Holt contextuality witness S defined in the spin and energy subsystems, observing a clear breach of the classical bound of |S|≤2, obtaining S=2.40±0.02. These entangled beams could enable alternative approaches for directly probing dynamics and entanglement in quantum materials whose low-energy excitation scales match those of the incident entangled neutron.
| Original language | English |
|---|---|
| Article number | L031005 |
| Journal | Physical Review Applied |
| Volume | 22 |
| Issue number | 3 |
| DOIs | |
| State | Published - Sep 2024 |
Funding
This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education for the DOE under Contract No. DE-SC0014664. This work was supported by the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Early Career Research Program Award (KC0402010,ERKCSA4), under Contract No. DE-AC05-00OR22725. This research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. G.O. gratefully acknowledges support from the Institute for Advanced Study. S.J.K. was partially supported by and the rf flipper used in Oak Ridge was constructed and optimized by Department of Energy STTR grants DE-SC0021482, DE-SC0018453 and DE-SC0023624. We gratefully acknowledge financial support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under TRR 360 (Project No. 492547816), the excellence cluster MCQST under Germany\u2019s Excellence Strategy EXC-2111 (Project No. 390814868), and the European Research Council (ERC) through Advanced Grant 788031 (ExQuiSid). This experiment was also attempted on the Larmor instrument at the ISIS Neutron and Muon source (UK) supported by a beamtime allocation RB2310511 from the Science and Technology Facilities Council . Acknowledgments. The authors gratefully acknowledge Doug Kyle, Kaleb Burrage, Lowell Crow, Goran Nilsen, and Mark Davenport for their assistance with experiments. Financial support by the German Bundesministerium f\u00FCr Bildung und Forschung (BMBF, Federal Ministry for Education and Research) through the Project No. 05K19W05 (\u201CResonante Longitudinale MIASANS Spin-Echo Spektroskopie an RESEDA\u201D) and Project No. 05K22WO2 (\u201CTransportierbare Vorrichtung zur r\u00E4umlichen Intensit\u00E4tsmodulation (SIM-Mode) von polarisierten Neutronenstrahlen am FRM-II\u201D) is gratefully acknowledged.