查看更多>>摘要：The field of topological photonics was initiated with the realization of a Chern insulator phase in a gyromagnetic photonic crystal(PhC)with broken time-reversal symmetry(T),hosting chiral edge states that are topologically protected propagating modes.Along a separate line of research,a quadrupole topological insulator was the first higher-order topological phase supporting localized corner states,but has been so far limited to T-invariant systems,as T is a key ingredient in early models.Here we report the realization of a quadrupole topological insulator phase in a gyromagnetic PhC,as a consequence of topological phase transition from the previously demonstrated Chern insulator phase.The phase transition has been demonstrated with microwave measurements,which characterize the evolution from propagating chiral edge states to localized comer states.We also demonstrate the migration of topological boundary states into the continuum,when the gyromagnetic PhC is magnetically tuned.These results extend the quadrupole topological insulator phase into T-broken systems,and integrate topologically protected propagating and localized modes in a magnetically tunable photonic crystal platform.
查看更多>>摘要：Photonic integrated quantum memories are essential for the construction of scalable quantum networks.Spin-wave quantum storage,which can support on-demand retrieval with a long lifetime,is indispensable for practical applications,but has never been demonstrated in an integrated solid-state device.Here,we demonstrate spin-wave quantum storage based on a laser-written waveguide fabricated in a151 Eu3+:Y2SiO5 crystal,using both the atomic frequency comb and noiseless photon-echo protocols.Qubits encoded with single-photon-level inputs are stored and retrieved with a fidelity of 94.9％±1.2％,which is far beyond the maximal fidelity that can be obtained with any classical device.Our results underline the potential of laser-written integrated devices for practical applications in large-scale quantum networks,such as the construction of multiplexed quantum repeaters in an integrated configuration and high-density transportable quantum memories.
Lan LiuZheng-Han LianAi-Ping LvNimaichand Salam...
55-69页
查看更多>>摘要：Candidate bacterial phylum CSP 1-3 has not been cultivated and is poorly understood.Here,we analyzed 112 CSP1-3 metagenome-assembled genomes and showed they are likely facultative anaerobes,with 3 of 5 families encoding autotrophy through the reductive glycine pathway(RGP),Wood-Ljungdahl pathway(WLP)or Calvin-Benson-Bassham(CBB),with hydrogen or sulfide as electron donors.Chemoautotrophic enrichments from hot spring sediments and fluorescence in situ hybridization revealed enrichment of six CSP1-3 genera,and both transcribed genes and DNA-stable isotope probing were consistent with proposed chemoautotrophic metabolisms.Ancestral state reconstructions showed that the ancestors of phylum CSP 1-3 may have been acetogens that were autotrophic via the RGP,whereas the WLP and CBB were acquired by horizontal gene transfer.Our results reveal that CSP 1-3 is a widely distributed phylum with the potential to contribute to the cycling of carbon,sulfur and nitrogen.The name Sysuimicrobiota phy.nov.is proposed.
查看更多>>摘要：The ability to rapidly recognize basic facial emotions(e.g.fear)is crucial for social interactions and adaptive functioning.To date,the origin of facial-emotion-recognition ability remains equivocal.Using a classical twin design in humans,we found a clear dissection of low and high spatial frequencies(LSF and HSF)in facial emotion perception:whereas genetic factors contributed to individual variation in LSF processing,HSF processing is largely shaped by environmental effects.Furthermore,the ability to recognize facial emotions of LSF content genetically correlated with the function of the amygdala.Crucially,single-unit recording of the amygdala in macaques further revealed the dissociation between LSF and HSF processing in facial emotion perception,indicating the existence of an evolutionarily conserved mechanism.This cross-species study enhances insights into the neurobiological dual-route model(subcortical vs.cortical)of emotion perception and illuminates the origin and the functional development of the emotional brain in primates.
查看更多>>摘要：The Chang'E-6(CE-6)mission successfully achieved return of the first samples from the far side of the Moon.The sampling site of CE-6 is located in the South Pole-Aitken(SPA)basin-the largest,deepest and oldest impact basin on the Moon.The 1935.3 g of CE-6 lunar samples exhibit distinct characteristics compared with previous lunar samples.This study analyses the physical,mineralogical,petrographic and geochemical properties of CE-6 lunar scooped samples.The CE-6 soil has a significantly lower bulk density(0.983 g/cm3)and true density(3.035 g/cm3)than the Chang'E-5(CE-5)samples.The grain size of the CE-6 soil exhibits a bimodal distribution,indicating a mixture of different compositions.Mineralogically,the CE-6 soil consists of 32.6％plagioclase(anorthite and bytownite),19.7％augite,10％pigeonite and 3.6％orthopyroxene,and with low content of olivine(0.5％)but high content of amorphous glass(29.4％).Geochemically,the bulk composition of CE-6 soil is rich in Al2O3(14％)and CaO(12％)but low in FeO(17％),and trace elements of CE-6 soil such as K(～630 ppm),U(0.26 ppm),Th(0.92 ppm)and rare-earth elements are significantly lower than those of the lunar soils within the Procellarum KREEP Terrane.The local basalts are characterized by low-Ti(TiO2,5.08％),low-Al(Al2O3 9.85％)and low-K(～830 ppm),features suggesting that the CE-6 soil is a mixture of local basalts and non-basaltic ejecta.The returned CE-6 sample contains diverse lithic fragments,including local mare basalt,breccia,agglutinate,glasses and leucocrate.These local mare basalts document the volcanic history of the lunar far side,while the non-basaltic fragments may offer critical insights into the lunar highland crust,SPA impact melts and potentially the deep lunar mantle,making these samples highly significant for scientific research.
查看更多>>摘要：The established paradigm assumes that drainage may decrease the vast soil organic carbon(SOC)reservoir in global wetlands.Yet drainage can also promote SOC stabilization by fostering the accrual of metal-bound organic carbon(bound OC)upon oxygen exposure.Here,this emergent mechanism is tested for the first time at a regional scale,using literature data and a nationwide,pairwise survey of drained wetlands across China.We show that long-term(15-55 years)drainage largely increased metallic protection of SOC(bound OC％)in non-Sphagnum wetlands,but consistently decreased bound OC％in Sphagnum wetlands following replacement of the'rust engineer'Sphagnum by herbaceous plants.Improved SOC stock estimates based on 66 soil profiles reveal that bound OC increases can compensate for the loss of unbound SOC components in non-Sphagnum wetlands with substantial accrual of reactive metals.Metallic stabilization of wetland SOC is hence a widespread but overlooked mechanism that is heavily influenced by vegetational shifts.Incorporating this novel mechanism into models will improve prediction of wetland SOC dynamics under shifting hydrological regimes.
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维普