98%
921
2 minutes
20
Secure key rate (SKR) of point-point quantum key distribution (QKD) is fundamentally bounded by the rate-loss limit. Recent breakthrough of twin-field (TF) QKD can overcome this limit and enables long distance quantum communication, but its implementation necessitates complex global phase tracking and requires strong phase references that not only add to noise but also reduce the duty cycle for quantum transmission. Here, we resolve these shortcomings, and importantly achieve even higher SKRs than TF-QKD, via implementing an innovative but simpler measurement-device-independent QKD that realizes repeaterlike communication through asynchronous coincidence pairing. Over 413 and 508 km optical fibers, we achieve finite-size SKRs of 590.61 and 42.64 bit/s, which are respectively 1.80 and 4.08 times of their corresponding absolute rate limits. Significantly, the SKR at 306 km exceeds 5 kbit/s and meets the bitrate requirement for live one-time-pad encryption of voice communication. Our work will bring forward economical and efficient intercity quantum-secure networks.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1103/PhysRevLett.130.250801 | DOI Listing |
Phys Rev Lett
August 2025
Universität Innsbruck, Institut für Experimentalphysik, Technikerstrasse 25, 6020 Innsbruck, Austria.
Establishing networks of quantum processors offers a path to scalable quantum computing and applications in communication and sensing. This requires first developing efficient interfaces between photons and multiqubit registers. In this Letter, we show how to entangle each individual matter qubit in a register of ten to a separate traveling photon.
View Article and Find Full Text PDFSci Adv
September 2025
James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK.
Narrow-linewidth lasers are essential for coherent optical applications, including communications, metrology, and sensing. Although compact semiconductor lasers with narrow linewidths have been demonstrated, achieving high spectral purity generally necessitates passive external cavities based on photonic integrated circuits. This study presents a theoretical and experimental demonstration of a monolithic optical injection locking topological interface state extended (MOIL-TISE) laser.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
RIKEN, Center for Quantum Computing, Wakoshi, Saitama 351-0198, Japan.
Disorder and non-Hermitian effects together can upend how waves localize. In a 1D disordered chain, the non-Hermitian skin effect (NHSE) can induce Anderson delocalization, defying the usual rule that disorder in low dimensions always localizes states. While weak disorder leaves the NHSE intact, strong disorder restores Anderson localization.
View Article and Find Full Text PDFLight Sci Appl
September 2025
Laboratory of Quantum Information, University of Science and Technology of China, 230026, Hefei, China.
Quantum imaging with spatially entangled photons offers advantages such as enhanced spatial resolution, robustness against noise, and counterintuitive phenomena, while a biphoton spatial aberration generally degrades its performance. Biphoton aberration correction has been achieved by using classical beams to detect the aberration source or scanning the correction phase on biphotons if the source is unreachable. Here, a new method named position-correlated biphoton Shack-Hartmann wavefront sensing is introduced, where the phase pattern added on photon pairs with a strong position correlation is reconstructed from their position centroid distribution at the back focal plane of a microlens array.
View Article and Find Full Text PDFJ Phys Chem Lett
September 2025
State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300401, P. R. China.
Quantum dots (QDs) converted to micro light-emitting diodes (LEDs) have emerged as a promising technology for next-generation display devices. However, their commercial application has been hindered by the susceptibility of QDs to photodegradation when directly exposed to an open environment. Here, we develop functional ligand zinc bis[2-(methacryloyloxy)ethyl] phosphate (Zn(BMEP)) to passivate QD surface anions through a phosphine-mediated surface reaction.
View Article and Find Full Text PDF