物理与天体物理最新文献

Single-cell circadian oscillators exchange extracellular information to sustain coherent circadian rhythms at the tissue level. The circadian clock and the cell cycle couple within cells but the mechanisms underlying this interplay are poorly understood. We show that the loss of extracellular circadian synchronization disrupts circadian and cell cycle coordination within individual cells, impeding collective tissue growth. We use the theory of coupled oscillators combined with live population, and single-cell recordings and precise experimental perturbations. Coherent circadian rhythms yield oscillatory growth patterns, which unveil a global timing regulator of tissue dynamics. Knocking out core circadian elements abolishes the observed effects, highlighting the central role of circadian clock regulation. Our results underscore the role of tissue-level circadian disruption in regulating proliferation, thereby linking disrupted circadian clocks with oncogenic processes. These findings illuminate the intricate interplay between circadian rhythms, cellular signalling and tissue physiology and enhance our understanding of tissue homeostasis and growth regulation in the context of both health and disease.

Previous theoretical efforts have predicted a type of unconventional antiferromagnet characterized by a crystal symmetry that connects antiferromagnetic sublattices in real space and simultaneously couples spin and momentum in reciprocal space. This results in a unique crystal-symmetry-paired spin–valley locking and related properties including piezomagnetism and non-collinear spin current even without spin–orbit coupling. However, most known unconventional antiferromagnets do not meet the necessary symmetry requirements for non-relativistic spin current, and this limits applications in spintronic devices. Here we demonstrate crystal-symmetry-paired spin–valley locking in a layered room-temperature antiferromagnetic compound, Rb_1−δV₂Te₂O. Spin-resolved photoemission measurements directly show the opposite spin splitting between crystal-symmetry-paired valleys. Quasi-particle interference patterns show the suppression of intervalley scattering due to the spin selection rules that are a direct consequence of the spin–valley locking. These results suggest that Rb_1−δV₂Te₂O is a potential room-temperature altermagnet candidate. Our observations highlight a methodology that enables both the advantages of layered materials and possible control through crystal symmetry manipulation for advancements in magnetism, electronics and information technology.

Collective behaviour in dense assemblies of self-propelled active particles occurs in a wide range of biological phenomena, including the dynamical transitions of cellular and subcellular biological assemblies such as the cytoskeleton and the cell nucleus. Here, motivated by observations of mechanically induced changes in the dynamics of such systems and the apparent role of confinement geometry, we show that the fluidization transition broadly resembles yielding in amorphous solids, which is consistent with recent suggestions. More specifically, however, we find that a detailed analogy holds with the yielding transition under cyclic shear deformation, for large but finite persistence times. The fluidization transition is accompanied by driving-induced annealing, strong dependence on the initial state of the system, a divergence of timescales to reach steady states and a discontinuous onset of diffusive motion. We also observe a striking dependence of transition on persistence times and on the nature of confinement. Collectively, our results have implications for biological assemblies in confined geometries, including epigenetic cell-state transitions.

The strongly lensed gravitational wave (SLGW) is a promising transient phenomenon. However, the long-wave nature of gravitational waves poses a considerable challenge in the identification of its host galaxy. Here, to tackle this challenge, we propose a method triggered by the wave optics effect of microlensing. The microlensing interference introduces frequency-dependent fluctuations in the waveform. Our method consists of three steps. First, we reconstruct the waveforms by using template-independent and template-dependent methods. The mismatch of two reconstructions serves as an indicator of SLGWs. This step can identify approximately 10% SLGWs. Second, we pair the multiple images of the SLGWs by using sky localization overlapping. Because we have preidentified at least one image through microlensing, the false-alarm probability for pairing SLGWs is significantly reduced. Third, we search the host galaxy by requiring the consistency of time delays between galaxy–galaxy lensing and SLGW. By combing the stage-IV galaxy survey and the third-generation gravitational wave detectors, we expect to find, on average, one quadruple-image system per 3 years. This method can substantially facilitate the pursuit of time-delay cosmography, discovery of compact objects and multimessenger astronomy.