In the diffraction-limited near-field propagation regime, free-space optical quantum key distribution (QKD) systems can employ multiple spatial modes to improve their key rate. This improvement can be effected by means of high-dimensional QKD or by spatial-mode multiplexing of independent QKD channels, with the latter, in general, offering higher key rates. Here, we theoretically analyze spatial-mode-multiplexed, decoy-state BB84 whose transmitter mode set is either a collection of phase-tilted, flat-top focused beams (FBs) or the Laguerre-Gaussian (LG) modes. Although for vacuum propagation the FBs suffer a QKD rate penalty relative to the LG modes, their potential ease of implementation make them an attractive alternative. Moreover, in the presence of turbulence, the FB modes may outperform the LG modes.
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Sci Rep
January 2025
College of Electrical and Information Engineering, Hunan University of Science and Technology, Xiangtan, 411201, Hunan, People's Republic of China.
The development and modification of grouting materials constitute crucial factors influencing the effectiveness of grouting. Given the pivotal role of water in the hydration of cement-based composite materials and construction processes, this study proposes an exploratory approach using green, economical magnetized water technology to enhance the performance of cement grouts. The research systematically investigates the effects of magnetized water on the fundamental grouting properties (stability, rheological behavior, and stone body strength) of cement grouts, prepared under varying magnetization conditions (including magnetic intensity, water flow speed, and cycle times).
View Article and Find Full Text PDFNat Mater
January 2025
School of Physics and Astronomy, Beijing Normal University, Beijing, China.
The coherent spin waves, magnons, can propagate without accompanying charge transports and Joule heat dissipation. Room-temperature and long-distance spin waves propagating within nanoscale spin channels are considered promising for integrated magnonic applications, but experimentally challenging. Here we report that long-distance propagation of chiral magnonic edge states can be achieved at room temperature in manganite thin films with long, antiferromagnetically coupled spin spirals (millimetre length) and low magnetic Gilbert damping (~3.
View Article and Find Full Text PDFNat Commun
January 2025
Shanghai Key Lab of Chemical Assessment and Sustainability, School of Chemical Science and Engineering, Tongji University, Shanghai, China.
Photocatalytic overall water splitting is a promising approach for a sustainable hydrogen provision using solar energy. For sufficient solar energy utilization, this reaction ought to be operated based on visible-light-active semiconductors, which is very challenging. In this work, an F-expedited nitridation strategy is applied to modify the wide-bandgap semiconductor SrTiO for visible-light-driven photocatalytic overall water splitting.
View Article and Find Full Text PDFNat Commun
January 2025
State Key Laboratory of Photovoltaic Science and Technology, Department of Materials Science, Institute of Optoelectronics, Fudan University, Shanghai, 200433, China.
Ferroelectric semiconductors have the advantages of switchable polarization ferroelectric field regulation and semiconductor transport characteristics, which are highly promising in ferroelectric transistors and nonvolatile memory. However, it is difficult to prepare a Sn-based perovskite film with both robust ferroelectric and semiconductor properties. Here, by doping with 2-methylbenzimidazole, Sn-based perovskite [93.
View Article and Find Full Text PDFSci Bull (Beijing)
December 2024
State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China. Electronic address:
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