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Non-Hermitian topological photonics plays a key role in bridging topological matter with gain and loss engineering in optics. Here we report the experimental observation of the break of chiral currents in a Hall ladder from the non-Hermiticity by constructing synthetic frequency dimension in two rings, where currents on both legs of the ladder co-propagate in the same direction. The origin of such phenomena is resulted from the interplay between the effective magnetic flux and the on-site gain and loss. Such non-Hermitian co-propagating currents exhibit characteristics of unidirectional frequency conversion in both rings, and moreover, different from the counterpart in Hermitian systems, can provide a method to probe the signatures of the non-Hermitian skin effect from steady-state bulk dynamics. Our model is further extended to models including next-nearest-neighbor couplings, pointing to a way for observing the non-Hermitian signature with higher winding number, and provides a new control knob for light manipulation with the topological dissipation engineering.
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http://dx.doi.org/10.1038/s41377-024-01700-1 | DOI Listing |
Nat Commun
August 2025
CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, China.
Investigating physical models with photonic synthetic dimensions has been generating great interest in vast fields of science. The rapidly developing thin-film lithium niobate (TFLN) platform, for its numerous advantages including high electro-optic coefficient and scalability, is well compatible with the realization of synthetic dimensions in the frequency together with spatial domain. While coupling resonators with fixed beam splitters is a common experimental approach, it often lacks tunability and limits coupling between adjacent lattices to sites occupying the same frequency domain positions.
View Article and Find Full Text PDFPhys Rev Lett
April 2025
Huazhong University of Science and Technology, Wuhan National Laboratory for Optoelectronics and School of Physics, Wuhan 430074, China.
Chiral edge states are a hallmark of topological physics, and the emergence of synthetic dimensions has provided ideal platforms for investigating chiral topology while overcoming the limitations of real space. Conventional studies have primarily concentrated on symmetric chiral behaviors, limited by complex and inflexible systems. Here, we demonstrate a programmable integrated photonic platform to generate and manipulate reconfigurable chiral edge states in synthetic dimensions within a single lithium niobate microring resonator.
View Article and Find Full Text PDFAnn Biomed Eng
June 2025
Department of Biomedical Engineering, Virginia Tech, 440 Kelly Hall, 325 Stanger Street MC 0298, Blacksburg, VA, 24061, USA.
Purpose: This study evaluates the accuracy of a model-based image matching (MBIM) approach with model calibration for tracking head impact speeds in uncalibrated spaces from single-camera views.
Methods: Two validation datasets were used. The first included 36 videos of guided NOCSAE headform drops at varying camera positions (heights, distances, camera angles) where a speed gate measured vertical impact speed.
Phys Rev Lett
February 2025
Ens de Lyon, CNRS, LPENSL, UMR 5672, F-69342 Lyon Cedex 07, France.
We use bosonization, retaining band curvature terms, to analyze the Hall response of interacting bosonic and fermionic two-leg ladders threaded by a flux. We derive an explicit expression of the Hall imbalance in a perturbative expansion in the band curvature, retaining fully the interactions. We show that the flux dependence of the Hall imbalance allows to distinguish the two phases (Meissner and vortex) that are present for a bosonic ladder.
View Article and Find Full Text PDFImplement Sci Commun
January 2025
Center for Health Equity Research, School of Medicine, University of North Carolina at Chapel Hill, 333 South Columbia Street, MacNider Hall Ste 323, Chapel Hill, NC, 27599, USA.
Background: African Americans experience cardiovascular disease (CVD) disparities, and the burden is greatest in the rural south. Although evidence-based CVD prevention and management programs have been tailored to this context, implementation has been limited and not sustained long-term. To understand how to implement and sustain evidence-based CVD programs at scale, we must explore the perspectives of organizations serving rural African American communities and situate findings within foundational Implementation Science frameworks.
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