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Abstract Quantum annealing, which involves quantum tunnelling among possible solutions, has state-of-the-art applications not only in quickly finding the lowest-energy configuration of a complex system, but also in quantum computing. Here we report a single-crystal study of the frustrated magnet α-CoV2O6, consisting of a triangular arrangement of ferromagnetic Ising spin chains without evident structural disorder. We observe quantum annealing phenomena resulting from time-reversal symmetry breaking in a tiny transverse field. Below ~ 1 K, the system exhibits no indication of approaching the lowest-energy state for at least 15 hours in zero transverse field, but quickly converges towards that configuration with a nearly temperature-independent relaxation time of ~ 10 seconds in a transverse field of ~ 3.5 mK. Our many-body simulations show qualitative agreement with the experimental results, and suggest that a tiny transverse field can profoundly enhance quantum spin fluctuations, triggering rapid quantum annealing process from topological metastable Kosterlitz-Thouless phases, at low temperatures.

Abstract The reversible transformation of a nanohelix is one of the most exquisite and important phenomena in nature. However, nanomaterials usually fail to twist into helical crystals. Considering the irreversibility of the previously studied twisting forces, the reverse process (untwisting) is more difficult to achieve, let alone the retwisting of the untwisted crystalline nanohelices. Herein, we report a new reciprocal effect between molecular geometry and crystal structure which triggers a twisting-untwisting-retwisting cycle for tri-cobalt salicylate hydroxide hexahydrate. The twisting force stems from competition between the condensation reaction and stacking process, different from the previously reported twisting mechanisms. The resulting distinct nanohelices give rise to unusual structure elasticity, as reflected in the reversible change of crystal lattice parameters and the mutual transformation between the nanowires and nanohelices. This study proposes a fresh concept for designing reversible processes and brings a new perspective in crystallography.

The antiferromagnetic topological insulator MnBi2Te4 exhibits Chern and axion insulator phases at low magnetic field; however, its behaviour in high magnetic field has remained unexplored. Here, using transport measurements at high magnetic field, the authors report a zero Hall plateau composed of two counter-propagating edge channels.

Mitochondrial apoptosis is controlled by BCL2 family proteins, and the BH3-only proteins often act as sensors that transmit apoptotic signals. Here the authors show how the BH3-only proteins BMF and HRK can directly activate the BCL2 protein BAK and interact with BAK through an alternative binding groove.

Colonoscopy is the most commonly used tool to screen for colorectal cancer (CRC). Here, the authors develop a deep learning model to perform optical diagnosis of CRC by training on a large data set of white-light colonoscopy images and achieve endoscopist-level performance on three independent datasets.

How sulfur dioxide emitted through coal combustion is oxidized to sulfate particles during winter haze pollution events has been the subject of debate. Here, the authors show that rapid oxidation takes place by nitrogen dioxide and nitrous acid, producing nitrous oxide together with sulfate.

Room-temperature solid-state single photon emitters in the telecom range are suitable for quantum communication. Here, the authors observe defects in high-purity 3C-SiC epitaxy layers grown on a silicon substrate, with good characteristics in terms of brightness, emission’s polarization and photostability.

Polo-like kinase 1 (Plk1) is a key regulator of mitosis. Here, the authors show that Plk1 activates the pentose phosphate pathway in cancer cells by directly phosphorylating glucose-6-phosphate dehydrogenase (G6PD) and that such activation is critical for cell cycle progression and cancer cell growth.

Anomalous conducting behavior of solids may reflect the presence of novel quantum states. Here, Zhang et al. report an increased conductivity in TaAs with a magnetic field applied along the direction of the current, which reveals an inherent property of the Weyl Fermion.