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Entanglement is crucial to many quantum applications, including quantum information processing, quantum simulation, and quantum-enhanced sensing. Because of their rich internal structure and interactions, molecules have been proposed as a promising platform for quantum science. Deterministic entanglement of individually controlled molecules has nevertheless been a long-standing experimental challenge. We demonstrate on-demand entanglement of individually prepared molecules. Using the electric dipolar interaction between pairs of molecules prepared by using a reconfigurable optical tweezer array, we deterministically created Bell pairs of molecules. Our results demonstrate the key building blocks needed for quantum applications and may advance quantum-enhanced fundamental physics tests that use trapped molecules.
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http://dx.doi.org/10.1126/science.adf4272 | DOI Listing |
Nature
July 2025
State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, China.
Spontaneous two-photon emission (STPE) is a second-order quantum radiation process with implications in astrophysics, atomic physics and quantum technology. In particular, on-demand STPE from single quantum emitters has long been predicted to revolutionize photonic quantum science and technology. Here we report STPE with brightness comparable to that of competing single-photon radiation from a single semiconductor quantum dot deterministically coupled to a high-quality micropillar cavity.
View Article and Find Full Text PDFSci Adv
July 2025
ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS), Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia.
Tunable biphoton quantum entanglement generated from nonlinear flat optics is highly desirable for cutting-edge quantum technologies, yet its tunability is substantially constrained by the symmetry of material nonlinear tensors. Here, we overcome this constraint by introducing symmetry breaking in nonlinear polarization via resonant metasurfaces. While asymmetric optical responses have enabled breakthroughs in classical applications like nonreciprocal light transmission, we report the experimental demonstration of asymmetric nonlinear responses for biphoton entanglement.
View Article and Find Full Text PDFNat Commun
May 2025
Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, F-38000, Grenoble, France.
Electronic flying qubits offer an interesting alternative to photonic qubits: electrons propagate slower, hence easier to control in real time, and Coulomb interaction enables direct entanglement between different qubits. Although their coherence time is limited, flying electrons in the form of picosecond plasmonic pulses could be competitive in terms of the number of achievable coherent operations. The key challenge in achieving this critical milestone is the development of a new technology capable of injecting 'on-demand' single-electron wavepackets into quantum devices, with temporal durations comparable to or shorter than the device dimensions.
View Article and Find Full Text PDFChem Asian J
June 2025
Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
Mechanochromic polymers have potential in visualization of microscopic damages in materials, and the integration of non-invasive switching into mechanochromic polymers can enable rich on-demand functionality of polymer materials. In this work, we report the development of a mechanoresponsive fluorescent polymer with photogated properties, comprising poly(methyl acrylate) (PMA) and the photoswitchable mechanophore SA, which features two anthracene groups linked by a disilane spacer. The mechanochromic polymer PMA-SA exhibits ratiometric fluorescence response upon mechanical deformation, which arises from the monomer and excimer emission ratio of anthracene controlled by the polymer strain.
View Article and Find Full Text PDFNat Commun
November 2024
Center for Quantum Information, IIIS, Tsinghua University, Beijing, 100084, PR China.
Distributing quantum entanglement between distant parties is a significant but difficult task in quantum information science, as it can enable numerous applications but suffers from exponential decay in the quantum channel. Quantum repeaters are one of the most promising approaches towards this goal. In a quantum repeater protocol, it is essential that the entanglement generation speed within each elementary link is faster than the memory decoherence rate, and this stringent requirement has not been implemented over a fiber of metropolitan scale so far.
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