Nearly one century after the birth of quantum mechanics, parity–time symmetry is revolutionizing and extending quantum theories to include a unique family of non-Hermitian Hamiltonians. While ...conceptually striking, experimental demonstration of parity–time symmetry remains unexplored in quantum electronic systems. The flexibility of photonics allows for creating and superposing non-Hermitian eigenstates with ease using optical gain and loss, which makes it an ideal platform to explore various non-Hermitian quantum symmetry paradigms for novel device functionalities. Such explorations that employ classical photonic platforms not only deepen our understanding of fundamental quantum physics but also facilitate technological breakthroughs for photonic applications. Research into non-Hermitian photonics therefore advances and benefits both fields simultaneously.
Twisted light on a chip Ge, Li
Science (American Association for the Advancement of Science),
05/2020, Letnik:
368, Številka:
6492
Journal Article
Recenzirano
Compact devices provide new ways to generate and detect optical vortex beams
A large-scale vortex is an extraordinary phenomenon to behold, be it a hurricane in the North Atlantic Ocean or the Great ...Red Spot on Jupiter. A vortex on a small scale is equally fascinating, especially when its quantum nature starts to emerge. Alexei Abrikosov won a Nobel Prize by introducing vortices in a phenomenological model to describe a new type of superconductor in 1950s (
1
), which turned out to be a feature of paired electrons in supercurrent. A very different type of vortex can be created for light (
2
). On pages 760 and 763 of this issue, Zhang
et al.
(
3
) and Ji
et al.
(
4
) demonstrate new ways to generate and detect such optical vortex beams on a tiny semiconductor chip.
With the prevalence of traceability technology in the turbulent Internet age, traceable food has become an important tool in addressing food safety issues. Under the combined effect of frequent food ...safety problems and sustainable development of traceability industry, the research on traceable food consumer behavior has become more extensive. However, it is still not fully understood how the multiple information brought by traceability affects consumers' purchase decision. This study proposes the effects of traceability knowledge, traceable information quality and traceable certification credibility on traceable food purchase intention
the mediation of perceived risk and perceived value, and integrates the moderating effect of peer influence in the context of Internet age into a research framework. The analytical results indicate that traceability knowledge, traceable information quality, and traceability certification credibility indirectly affect consumers' traceable food purchase intention through perceived risk and perceived value, while traceability knowledge, perceived risk, and perceived value directly affect "traceable food purchase intention." Furthermore, peer influence was found to be a significant moderator in the relationship between perceived risk (perceived value) and "traceable food purchase intention." Finally, based on the research results, traceability companies are suggested to focus on cultivating the traceable consumption habits. Meanwhile, although traceable food quality is the top priority, companies should also attach importance to the communication and interaction with consumer.
Amidst the industrial transformation and upgrade, the new energy vehicle industry is at a crucial juncture. Power batteries, a vital component of new energy vehicles, are currently at the forefront ...of industry competition with a focus on technological innovation and performance enhancement. The operational temperature of a battery significantly impacts its efficiency, making the design of a reliable Thermal Management System (TMS) essential to ensure battery safety and stability. Cylindrical power batteries are widely utilized in the industry. This article outlines the four main structures and their drawbacks of TMS for cylindrical power batteries. Among these structures, air cooling falls short in meeting high heat dissipation requirements. Liquid cooling is expensive, intricate, and adds considerable weight. Phase Change Materials (PCM) are not yet prevalent in practical applications. Similarly, heat pipes are relatively uncommon in large high-power battery packs. To better align with the new energy vehicle industry’s demands for top-notch performance, cost-effectiveness, eco-friendliness, and reliability, this paper strongly recommends delving deeper into composite cooling solutions. The construction of an economically viable and fully optimized composite cooling method is poised to become a significant scientific challenge for future research endeavors.
Ferroptosis is characterized by the accumulation of iron-derived reactive oxygen species (ROS). Ferroptosis causes neuronal death in multiple neurological disorders. Dexmedetomidine (Dex), an ...extensively used anesthetic, has neuroprotective effects against ROS, but its effect on iron metabolism remains unknown. In this study, SK-N-SH cells were treated with Dex for 24 h before treatment with 100 µM tert-butyl hydroperoxide (t-BHP; an ROS inducer) for 1 h. Afterward, intracellular ROS and labile ferrous iron Fe(II) levels were assessed. Dex hindered the increase in cellular ROS and labile Fe(II) levels caused by t-BHP, although Dex alone had no effect on labile Fe(II) level. t-BHP increased the expression of iron importers, transferrin receptor-1 and divalent metal transporter-1, and iron regulatory protein 1 and 2. These effects were abrogated by Dex treatment and SP-1 knockdown. t-BHP increased the phosphorylation of c-Jun N-terminal kinase (JNK) and signal transducer and activator of transcription 4 (STAT4), the primary up-stream activators of SP-1, but Dex decreased this. This study, for the first time, revealed that the antioxidative effect of Dex is partly associated to the inhibition of intracellular iron accumulation induced by t-BHP. Dex regulates iron metabolism by regulating iron importers and exporters through JNK/Sp1 and Stat4/Sp1 signaling. It is worth investigating whether Dex can protect neurons from ferroptosis.
Metabolic reprogramming is a hallmark of cancer. However, systematic characterizations of metabolites in triple-negative breast cancer (TNBC) are still lacking. Our study profiled the polar ...metabolome and lipidome in 330 TNBC samples and 149 paired normal breast tissues to construct a large metabolomic atlas of TNBC. Combining with previously established transcriptomic and genomic data of the same cohort, we conducted a comprehensive analysis linking TNBC metabolome to genomics. Our study classified TNBCs into three distinct metabolomic subgroups: C1, characterized by the enrichment of ceramides and fatty acids; C2, featured with the upregulation of metabolites related to oxidation reaction and glycosyl transfer; and C3, having the lowest level of metabolic dysregulation. Based on this newly developed metabolomic dataset, we refined previous TNBC transcriptomic subtypes and identified some crucial subtype-specific metabolites as potential therapeutic targets. The transcriptomic luminal androgen receptor (LAR) subtype overlapped with metabolomic C1 subtype. Experiments on patient-derived organoid and xenograft models indicate that targeting sphingosine-1-phosphate (S1P), an intermediate of the ceramide pathway, is a promising therapy for LAR tumors. Moreover, the transcriptomic basal-like immune-suppressed (BLIS) subtype contained two prognostic metabolomic subgroups (C2 and C3), which could be distinguished through machine-learning methods. We show that N-acetyl-aspartyl-glutamate is a crucial tumor-promoting metabolite and potential therapeutic target for high-risk BLIS tumors. Together, our study reveals the clinical significance of TNBC metabolomics, which can not only optimize the transcriptomic subtyping system, but also suggest novel therapeutic targets. This metabolomic dataset can serve as a useful public resource to promote precision treatment of TNBC.
Using the correspondence between (saturated) nonlinear and (unsaturated) linear dielectric constants, we propose a simple and systematic method to achieve selective excitation of lasing modes that ...would have been dwarfed by more dominant ones of lower thresholds. The key element of this method is incorporating the control of modal interactions into the spatial pump profile, and it is most valuable in the presence of spatially and spectrally overlapping modes, where it would be difficult to achieve selective excitation otherwise.
We show the existence of a flatband consisting of photonic zero modes in a gain and loss modulated lattice system as a result of the underlying non-Hermitian particle-hole symmetry. This general ...finding explains the previous observation in parity-time symmetric systems where non-Hermitian particle-hole symmetry is hidden. We further discuss the defect states in these systems, whose emergence can be viewed as an unconventional alignment of a pseudospin under the influence of a complex-valued pseudomagnetic field. These defect states also behave as a chain with two types of links, one rigid in a unit cell and one soft between unit cells, as the defect states become increasingly localized with the gain and loss strength.
Non-Hermitian systems based on parity-time (PT) and anti-PT symmetry reveal rich physics beyond the Hermitian regime. So far, realizations of such symmetric systems have been limited to the spatial ...domain. Here we theoretically and experimentally demonstrate synthetic anti-PT symmetry in a spectral dimension induced by nonlinear Brillouin scattering in a single optical microcavity, where Brillouin scattering induced transparency or absorption in two spectral resonances provides the optical gain and loss to observe a phase transition between two symmetry regimes. This scheme provides a new paradigm towards the investigation of non-Hermitian physics in a synthetic photonic dimension for all-optical signal processing and quantum information science.
We consider the role of degeneracy in parity-time (PT ) symmetry breaking for non-Hermitian wave equations beyond one dimension. We show that if the spectrum is degenerate in the absence of T ...breaking, and T is broken in a generic manner (without preserving other discrete symmetries), then the standard PT symmetry-breaking transition does not occur, meaning that the spectrum is complex even for infinitesimal strength of gain and loss. However, the realness of the entire spectrum can be preserved over a finite interval if additional discrete symmetries χ are imposed when T is broken, if χ decouples all degenerate modes. When the decoupling holds only for a subset of the degenerate spectrum, there can be a partial PT transition in which this subset remains real over a finite interval of T breaking. If the spectrum has odd degeneracy, a fraction of the degenerate spectrum can remain in the symmetric phase even without imposing additional discrete symmetries, and they are analogous to dark states in atomic physics. These results are illustrated by the example of different T -breaking perturbations of a uniform dielectric disk and sphere, and a group-theoretical analysis is given in the disk case. Finally, we show that multimode coupling is capable of restoring the PT -symmetric phase at finite T breaking. We also analyze these questions when the parity operator is replaced by another spatial symmetry operator and find that the behavior can be qualitatively different.
PDF
