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Scaling up the radiance of coupled laser arrays has been a long-standing challenge in photonics. In this study, we demonstrate that notions from supersymmetry—a theoretical framework developed in high-energy physics—can be strategically used in optics to address this problem. In this regard, a supersymmetric laser array is realized that is capable of emitting exclusively in its fundamental transverse mode in a stable manner. Our results not only pave the way toward devising new schemes for scaling up radiance in integrated lasers, but also, on a more fundamental level, could shed light on the intriguing synergy between non-Hermiticity and supersymmetry.

The exceptional properties exhibited by two-dimensional materials, such as graphene, are rooted in the underlying physics of the relativistic Dirac equation that describes the low energy excitations of such molecular systems. In this study, we explore a periodic lattice that provides access to the full solution spectrum of the extended Dirac Hamiltonian. Employing its photonic implementation of evanescently coupled waveguides, we indicate its ability to independently perturb the symmetries of the discrete model (breaking, also, the barrier towards the type-II phase) and arbitrarily define the location, anisotropy, and tilt of Dirac cones in the bulk. This unique aspect of topological control gives rise to highly versatile edge states, including an unusual class that emerges from the type-II degeneracies residing in the complex space of k. By probing these states, we investigate the topological nature of tilt and shed light on novel transport dynamics supported by Dirac configurations in two dimensions. The electrons in 2D materials like graphene are described by the relativistic Dirac equation. Here the authors present a lattice of evanescently coupled waveguides that emulates a wide range of Dirac excitations and study the type-II edge states that emerge in this photonic system.

In systems exhibiting the non-Hermitian skin effect (NHSE), higher-order exceptional points (EPs) exhibit unique characteristics making them invaluable for enhanced lasing and sensing operations. When these critical degeneracies reach a maximal order, equal to the system size N , they induce a collapse of the spectrum, not only into a singular eigenstate but also a singular point in physical space. To date, NHSE EPs of maximal order have been predicted in nonreciprocal systems, such as the Hatano-Nelson lattice, where this collapse occurs in the limit of infinite anisotropy. Challenging this perspective, we demonstrate that reciprocal Floquet systems are capable of exhibiting skin localization of arbitrary strength—ranging from mild localization, to the extreme regime of maximal-order exceptional points. By employing PT -symmetry in both space and time, we uncover a unique stroboscopic effect that results in the complete localization of the field amplitude at the edge of the lattice. A phase transition at a critical coupling strength leads to a regime with infinite NHSE EP solutions of maximal-order. Our results are broadly applicable to photonic, acoustic, and electronic systems, allowing one to leverage the dynamics of these valuable degeneracies in entirely new platforms, eliminating the need for critical asymmetric transmission. In non-Hermitian systems, higher-order exceptional points (EPs) and non-Hermitian Skin Effect (NHSE) offer powerful tools for enhanced sensing and lasing. Here, the authors show that reciprocal Floquet lattices with space-time PT-symmetry can host maximal-order NHSE EPs and extreme skin localization without requiring nonreciprocity.

A systematic method for the efficient design of narrowband filters founded on the extraordinary transmission via single fishnet structures (SFSs) is presented in this paper. Essentially, due to its strong resonant behavior, this phenomenon is proven suitable for the implementation of high-Q devices. The new design formulas are derived through the combination of full-wave numerical simulations and curve fitting algorithms. Also, adequate mathematical criteria are defined for the evaluation of the filters' linear performance, indicating that the transmitted electromagnetic waves remain practically undistorted in the frequency band of interest. Then, by exploiting the previously developed relations, proper correction factors are introduced in the existing SFS equivalent circuit expressions, which hardly increase the overall computational complexity. This quantitative modification leads to an enhanced characterization of SFSs, as key components for diverse applications. Finally, several limitations as well as possible ways of extending the featured algorithm to more complicated structures and higher frequency bands are briefly discussed.

We find exact solutions describing bidirectional pulses propagating in fiber Bragg gratings. They are derived by solving the coupled-mode theory equations and are expressed in terms of products of modified Bessel functions with algebraic functions. Depending on the values of the two free parameters the general bidirectional X-wave solution can also take the form of a unidirectional pulse. We analyze the symmetries and the asymptotic properties of the solutions and also discuss about additional waveforms that are obtained by interference of more than one solutions. Depending on their parameters such pulses can create a sharp focus with high contrast.

The theoretical framework of supersymmetry (SUSY) aims to relate bosons and fermions -- two profoundly different species of particles -- and their interactions. While this space-time symmetry is seen to provide an elegant solution to many unanswered questions in high-energy physics, its experimental verification has so far remained elusive. Here, we demonstrate that, notions from supersymmetry can be strategically utilized in optics in order to address one of the longstanding challenges in laser science. In this regard, a supersymmetric laser array is realized, capable of emitting exclusively in its fundamental transverse mode. Our results not only pave the way towards devising new schemes for scaling up radiance in integrated lasers, but also on a more fundamental level, they could shed light on the intriguing synergy between non-Hermiticity and supersymmetry.

Several studies have documented fish populations changing in response to long-term warming. Over the past decade, sea surface temperatures in the Gulf of Maine increased faster than 99% of the global ocean. The warming, which was related to a northward shift in the Gulf Stream and to changes in the Atlantic Multidecadal Oscillation and Pacific Decadal Oscillation, led to reduced recruitment and increased mortality in the region's Atlantic cod (Gadus morhua) stock. Failure to recognize the impact of warming on cod contributed to overfishing. Recovery of this fishery depends on sound management, but the size of the stock depends on future temperature conditions. The experience in the Gulf of Maine highlights the need to incorporate environmental factors into resource management.

Obstructive sleep apnea (OSA) has been associated with incidence of cardiovascular disease and with nocturnal angina, but evidence of a link with coronary atherosclerosis and myocardial ischemia is limited and previous studies may have been affected by selection bias or unmeasured confounding factors. We performed overnight polysomnography in 178 older male twins. The Apnea/Hypopnea Index (AHI) was calculated to assess OSA from the overnight sleep evaluation. AHI ≥15 was used as indicator of moderate/severe OSA. The following day, twins underwent myocardial perfusion imaging with [82Rb]-chloride positron emission tomography. Quantitative and semiquantitative measures of myocardial perfusion and absolute myocardial blood flow were obtained. The mean age was 68 years and 40% of the sample had an AHI≥15, which indicates moderate to severe OSA. Abnormal myocardial perfusion, both with stress and at rest, was more common in twins with elevated AHI. After adjusting for clinical, lifestyle and behavioral factors, and previous history of cardiovascular disease, twins with AHI ≥15 had 3.6 higher odds (95% CI, 1.5-8.9) of an abnormal total severity score, defined as a score ≥100, and for each 5-point increment in AHI, the odds of abnormality increased by 20% (95% CI, 7%-34%). Twin pairs where both twins had OSA exhibited the greatest risk. There were no differences in measures of ischemia and absolute myocardial blood flow and flow reserve by AHI status. OSA is associated with myocardial perfusion abnormalities that suggest prior subclinical myocardial scarring or infarction. Early environmental factors that affect both twins equally may play a role and should be further explored.

Background Foodborne outbreaks of Salmonella remain a pressing public health concern. We recently detected a large outbreak of Salmonella enterica serovar Enteritidis phage type 14b affecting more than 30 patients in our hospital. This outbreak was linked to community, national and European-wide cases. Hospital patients with Salmonella are at high risk, and require a rapid response. We initially investigated this outbreak by whole-genome sequencing using a novel rapid protocol on the Illumina MiSeq; we then integrated these data with whole-genome data from surveillance sequencing, thereby placing the outbreak in a national context. Additionally, we investigated the potential of a newly released sequencing technology, the MinION from Oxford Nanopore Technologies, in the management of a hospital outbreak of Salmonella . Results We demonstrate that rapid MiSeq sequencing can reduce the time to answer compared to the standard sequencing protocol with no impact on the results. We show, for the first time, that the MinION can acquire clinically relevant information in real time and within minutes of a DNA library being loaded. MinION sequencing permits confident assignment to species level within 20 min. Using a novel streaming phylogenetic placement method samples can be assigned to a serotype in 40 min and determined to be part of the outbreak in less than 2 h. Conclusions Both approaches yielded reliable and actionable clinical information on the Salmonella outbreak in less than half a day. The rapid availability of such information may facilitate more informed epidemiological investigations and influence infection control practices.

The distribution, phenology, and population dynamics of species at multiple trophic levels have been impacted by climate change across a range of spatial scales. Upper trophic level species may be uniquely impacted through changes to prey species and foraging habitats in space and time. Improving our understanding of how known changes in the abundance and distribution of prey species influence prey availability for marine predators is key to understanding climate impacts on upper trophic level species. Rorquals, a group of baleen whales, are generalist feeders that employ lunge feeding to engulf large volumes of water and prey, thereby requiring dense aggregations of prey for efficient feeding. While climate‐driven changes have been well documented for some species of fish and invertebrates consumed by rorquals, changes to the distribution of rorqual prey in aggregate and the implications of these changes for rorqual foraging habitat have received little attention. We used a 40‐year time series of prey data to assess spatial and temporal shifts in key prey groups for four rorqual species in the rapidly warming Northeast United States. We found notable changes to the distribution and biomass of prey groups for rorquals through space and time. The center of biomass of key large‐bodied prey showed significant poleward shifts and biomass increased in the northern portion of the Northeast United States. Accordingly, we found significant increases in the biomass of large‐bodied humpback, minke, and fin whale prey in the northerly Gulf of Maine and George's Bank regions, with concurrent decreases in the biomass of large‐bodied humpback whale prey in more southernly Mid‐Atlantic Bight and Southern New England regions. In contrast, there was little evidence of change in the distribution and biomass of smaller prey groups, which are of key importance for sei and fin whales. Our results suggest that rorquals that primarily consume large‐bodied prey, humpback and minke whales, may be more likely to be impacted by climate‐driven shifts in prey than sei and fin whales that feed on smaller prey. Assessments of changing prey distributions are needed for proactive management in light of climate‐driven impacts on whale foraging habitat.