1月18日，中国科大陈杨教授、哈工大深圳校区肖淑敏教授与新加坡国立仇成伟教授共同合作，以“Observation of intrinsic chiral bound states in the continuum”为题，在《nature》发表了微纳光学与手性光学的交叉领域进展论文。
编译 | 未玖Nature, 4 July 2024, VOL 631, ISSUE 8019《自然》2024年7月4日，第631卷，8019期材料科学Materials ScienceFabrication of red-emitting perovskite LEDs by
编译 | 李言Nature, 31 August 2023, Volume 620 Issue 7976《自然》2023年8月31日，第620卷，7976期天文学AstronomyA binary pulsar in a 53-minute orbit轨道周期为53分钟的脉冲星双
Abstract:Here we report the highest magmatic 3He/4He ratio yet measured in terrestrial igneous rocks， in olivines from Baffin Island lavas. We argue that the extremely high-3He/4He helium in these lavas might derive from Earth’s core. The viability of the core hypothesis relaxes the long-standing constraint—based on noble gases in lavas associated with mantle plumes globally—that volatile elements from the solar nebula have survived in the mantle since the early stages of accretion.
编译 | 李言Nature, 8 August 2024, Volume 632 Issue 8024《自然》2024年8月8日，第632卷，8024期物理学PhysicsAntiferromagnetic phase transition in a 3D fermionic H
编译 | 李言Nature, 29 June 2023, Volume 618 Issue 7967《自然》2023年6月29日，第618卷，7967期天文学AstronomyA close-in giant planet escapes engulfment by its st
Abstract:Galaxies in the Universe are distributed in a web-like structure characterized by different large-scale environments: dense clusters， elongated filaments， sheetlike walls and under-dense regions， called voids. The low density in voids is expected to affect the properties of their galaxies. Indeed， previous studies have shown that galaxies in voids are， on average， bluer and less massive， and have later morphologies and higher current star formation rates than galaxies in denser large-scale environments. However， it has never been observationally proved that the star formation histories in voids are substantially different from those in filaments， walls and clusters. Here we show that void galaxies have had， on average， slower SFHs than galaxies in denser large-scale environments. We also find two main SFH types present in all the environments: ‘short-timescale’ galaxies are not affected by their large-scale environment at early times but only later in their lives;
μm， resolving polarization in both the rings and the gaps. We find that the gaps have polarization angles with a notable azimuthal component and a higher polarization fraction than the rings. Our models show that the disk polarization is due to both scattering and emission from the aligned effectively prolate grains. The intrinsic polarization of aligned dust grains is probably more than 10%， which is much higher than that expected in low-resolution observations . Asymmetries and dust features that are not seen in non-polarimetric observations are seen in the polarization observations.
Abstract:Decay of a particle into more particles is a ubiquitous phenomenon to interacting quantum systems， taking place in colliders， nuclear reactors or solids. In a nonlinear medium， even a single photon would decay by down-converting into lower-frequency photons with the same total energy， at a rate given by Fermi’s golden rule. However， the energy-conservation condition cannot be matched precisely if the medium is finite and only supports quantized modes. Here we implement such an experiment using a superconducting multimode cavity， the nonlinearity of which was tailored to strongly violate the photon-number conservation. The resulting interaction attempts to convert a single photon excitation into a shower of low-energy photons but fails owing to the many-body localization mechanism， which manifests as a striking spectral fine structure of multiparticle resonances at the standing-wave-mode frequencies of the cavity. Each resonance was identified as a many-body state of radiation composed of photons from a broad frequency range and not obeying Fermi’s golden rule theory. Our result introduces a new platform to explore the fundamentals of many-body localization without having to control many atoms or qubits.
编译 | 冯维维Nature, Volume 635 Issue 8037, 7 November 2024《自然》, 第635卷，8037期，2024年11月7日物理学PhysicsPreferential occurrence of fast radio bursts in
Galaxy clusters magnify background objects through strong gravitational lensing. Typical magnifications for lensed galaxies are factors of a few but can also be as high as tens or hundreds， stretching galaxies into giant arcs. Individual stars can attain even higher magnifications given fortuitous alignment with the lensing cluster. Recently， several individual stars at redshifts between approximately 1 and 1.5 have been discovered， magnified by factors of thousands， temporarily boosted by microlensing. Here we report observations of a more distant and persistent magnified star at a redshift of 6.2 ± 0.1， 900 million years after the Big Bang. This star is magnified by a factor of thousands by the foreground galaxy cluster lens WHL0137–08 ， as estimated by four independent lens models. Unlike previous lensed stars， the magnification and observed brightness have remained roughly constant over 3.5 years of imaging and follow-up. The delensed absolute UV magnitude， −10 ± 2， is consistent with a star of mass greater than 50 times the mass of the Sun. Confirmation and spectral classification are forthcoming from approved observations with the James Webb Space Telescope.
For decades we have known that the Sun lies within the Local Bubble， a cavity of low-density， high-temperature plasma surrounded by a shell of cold， neutral gas and dust. However， the precise shape and extent of this shell， the impetus and timescale for its formation， and its relationship to nearby star formation have remained uncertain， largely due to low-resolution models of the local interstellar medium. Here we report an analysis of the three-dimensional positions， shapes and motions of dense gas and young stars within 200 pc of the Sun， using new spatial and dynamical constraints. We find that nearly all of the star-forming complexes in the solar vicinity lie on the surface of the Local Bubble and that their young stars show outward expansion mainly perpendicular to the bubble’s surface. Tracebacks of these young stars’ motions support a picture in which the origin of the Local Bubble was a burst of stellar birth and then death taking place near the bubble’s centre beginning approximately 14 Myr ago. The expansion of the Local Bubble created by the supernovae swept up the ambient interstellar medium into an extended shell that has now fragmented and collapsed into the most prominent nearby molecular clouds， in turn providing robust observational support for the theory of supernova-driven star formation.
编译 | 冯维维Nature, Volume 625 Issue 7993, 4 January 2024《自然》第625卷，7993期，2024年1月4日行星科学Planetary scienceSO2 , silicate clouds, but no CH4 detecte
编译 | 未玖Nature, 15 June 2023, VOL 618, ISSUE 7965《自然》2023年6月15日，第618卷，7965期天文学AstronomyDetection of phosphates originating from Enceladus’s o
Oxidation can deteriorate the properties of copper that are critical for its use， particularly in the semiconductor industry and electro-optics applications. Here we report the fabrication of copper thin films that are semi-permanently oxidation resistant because they consist of flat surfaces with only occasional mono-atomic steps. First-principles calculations confirm that mono-atomic step edges are as impervious to oxygen as flat surfaces and that surface adsorption of O atoms is suppressed once an oxygen face-centred cubic surface site coverage of 50% has been reached. These combined effects explain the exceptional oxidation resistance of ultraflat Cu surfaces.
Abstract:Before the Perseverance rover landing， the acoustic environment of Mars was unknown. Models predicted that: atmospheric turbulence changes at centimetre scales or smaller at the point where molecular viscosity converts kinetic energy into heat， the speed of sound varies at the surface with frequency and high-frequency waves are strongly attenuated with distance in CO2. However， theoretical models were uncertain because of a lack of experimental data at low pressure and the difficulty to characterize turbulence or attenuation in a closed environment. Here， using Perseverance microphone recordings， we present the first characterization of the acoustic environment on Mars and pressure fluctuations in the audible range and beyond， from 20 Hz to 50 kHz. We find that atmospheric sounds extend measurements of pressure variations down to 1，000 times smaller scales than ever observed before， showing a dissipative regime extending over five orders of magnitude in energy. Using point sources of sound ， we highlight two distinct values for the speed of sound that are about 10 m s−1 apart below and above 240 Hz， a unique characteristic of low-pressure CO2-dominated atmosphere. We also provide the acoustic attenuation with distance above 2 kHz， allowing us to explain the large contribution of the CO2 vibrational relaxation in the audible range. These results establish a ground truth for the modelling of acoustic processes， which is critical for studies in atmospheres such as those of Mars and Venus.
Magnetars are strongly magnetized， isolated neutron stars with magnetic fields up to around 1015 gauss， luminosities of approximately 1031-1036 ergs per second and rotation periods of about 0.3–12.0 s. Very energetic giant flares from galactic magnetars have been detected in hard X-rays and soft γ-rays， and only one has been detected from outside our galaxy. During such giant flares， quasi-periodic oscillations with low and high frequencies have been observed， but their statistical significance has been questioned. High-frequency QPOs have been seen only during the tail phase of the flare. Here we report the observation of two broad QPOs at approximately 2，132 hertz and 4，250 hertz in the main peak of a giant γ-ray flare in the direction of the NGC 253 galaxy， disappearing after 3.5 milliseconds. The flare was detected on 15 April 2020 by the Atmosphere–Space Interactions Monitor instrument aboard the International Space Station， which was the only instrument that recorded the main burst phase in the full energy range without suffering from saturation effects such as deadtime and pile-up. Along with sudden spectral variations， these extremely high-frequency oscillations in the burst peak are a crucial component that will aid our understanding of magnetar giant flares.
