Uniform Loss Enables Unidirectional Edge Transport in Photonic Crystals via Non-Hermitian Skin Effects
Researchers demonstrated theoretically and experimentally that uniform loss in photonic crystals can induce unidirectional-like edge transport by activating non-Hermitian skin effects. This mechanism converts normally bidirectional interface states into one-way wave propagation around domain walls. The finding offers a simpler, structurally straightforward approach to achieving directional wave transport without requiring engineered nonreciprocity or spatially patterned loss.
A new study shows that uniform loss—a simple and previously overlooked mechanism—can enforce unidirectional-like edge transport in photonic crystals by activating non-Hermitian skin effects (NHSEs). The researchers used a core-cladding geometry where domains share identical Chern numbers but possess distinct bulk polarizations. Uniform loss reshapes the spectral topology of edge bands, creating point gap windings that enforce one-way propagation. Near-field measurements confirmed that loss converts intrinsically bidirectional interface states into unidirectional-like circulation around the entire domain wall, with results showing excellent agreement with theoretical predictions. This work establishes uniform loss as a universal and structurally simple route for achieving directional wave transport in photonic systems.
What's missing
The study's own limitations and open questions are not detailed in the abstract provided, such as scalability to other wavelengths, practical loss tolerances, or potential applications beyond photonic crystals.
What different sources said
- arXiv physicsCenter
Unidirectional-like Edge Transport Induced by Non-Hermitian Skin Effects
Related
Gut Bacteria Enzyme Found to Break Down Heat-Processed Food Compounds, Producing Novel Biogenic Amines
Researchers have discovered that an enzyme in common gut bacteria can degrade N-epsilon-carboxymethyllysine (CML), a compound formed during thermal food processing, producing previously unknown biogenic amines. The enzyme, ornithine decarboxylase SpeC from enterobacteria, acts on CML and related modified lysine derivatives through a low-level 'underground' catalytic activity. This finding suggests a previously unrecognized communication axis between thermally processed dietary compounds and gut microbial physiology, with potential implications for host health.
Full-Length Gene Sequencing Reveals Two Distinct Bacterial Communities in Black-Legged Ticks Expanding Into Canada
Researchers used Oxford Nanopore full-length 16S rRNA gene sequencing to characterize the microbiome of Ixodes scapularis black-legged ticks collected in Nova Scotia, Canada, distinguishing between tick-adapted bacteria and environmentally acquired bacteria. The study comes as I. scapularis — the primary vector of Lyme disease — is rapidly expanding northward into Canada due to climate change. The findings suggest that environmentally derived bacteria in tick microbiomes are not mere contamination, which has implications for how tick microbiome data is collected and interpreted across surveillance studies.
Study Identifies Metabolic Link Between Cell Envelope Stress and Biofilm Formation in Bacteria
Researchers have discovered that the metabolite acetyl-CoA directly inhibits enzymes that degrade the bacterial signaling molecule c-di-GMP, connecting cell envelope biosynthesis stress to biofilm formation in Pseudomonas aeruginosa. The study found that sub-inhibitory concentrations of antibiotics targeting early peptidoglycan biosynthesis — but not other antibiotic classes — elevate c-di-GMP levels by reducing phosphodiesterase activity, with acetyl-CoA competing for the enzyme active site. Because the relevant enzyme domain is broadly conserved across bacterial species, this checkpoint mechanism may be widespread and could have implications for understanding antibiotic-induced biofilm responses.