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Anomalous properties of spark plasma sintered boron nitride solids

Materials Today 2025年 86卷 42-51页

作者： Biswas, Abhijit Serles, Peter Alvarez, Gustavo A. Schimpf, Jesse Hache, Michel Kong, Jonathan Demingos, Pedro Guerra Yuan, Bo Pieshkov, Tymofii S. Li, Chenxi Puthirath, Anand B. Gao, Bin Gray, Tia Zhang, Xiang Murukeshan, Jishnu Vajtai, Robert Dai, Pengcheng Singh, Chandra Veer Howe, Jane Zou, Yu Martin, Lane W. Clancy, James Patrick Tian, Zhiting Filleter, Tobin Ajayan, Pulickel M. Department of Materials Science and Nanoengineering Rice University HoustonTX77005 United States Department of Mechanical & Industrial Engineering University of Toronto 5 King's College Road TorontoM5S 3G8 Canada Sibley School of Mechanical and Aerospace Engineering Cornell University IthacaNY14853 United States Department of Materials Science and Engineering University of California Berkeley94720 United States Department of Materials Science and Engineering University of Toronto 184 College St TorontoM5S 3E4 Canada Department of Physics and Astronomy McMaster University HamiltonL8S 4M1 Canada Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Physics and Astronomy Rice University HoustonTX77005 United States Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley94720 United States

Hexagonal boron nitride (h-BN) is a brittle ceramic with a layered structure, however, recent experiments have suggested that inter-layer structural engineering could be key to new structural and functional properties. Here we report the scalable bulk synthesis of high-density crystalline h-BN solids, by using high-temperature spark plasma sintering (SPS) of h-BN powders, which show high values of mechanical strength, ductility, dielectric constant, thermal conductivity, and exceptional neutron radiation shielding capability. Through exhaustive characterizations we reveal that SPS induces non-basal plane crystallinity, twisting of layers, and facilitates inter-grain fusion with a high degree of in-plane alignment across macroscale dimensions, resulting in near-theoretical density and improved properties. Our findings highlight the importance of material design, via new approaches such as layer twisting and interlayer interconnections, to create novel ceramics with properties that could go beyond their intrinsic limits. © 2025

关键词： Ductility

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The probability for chiral oscillation of Majorana neutrino in Quantum Field Theory

arXiv

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arXiv 2025年

作者： Morozumi, Takuya Tahara, Tomoharu Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima Higashi-Hiroshima739-8526 Japan Core of Research for the Energetic Universe Hiroshima University Hiroshima Higashi-Hiroshima739-8526 Japan

We derive the probability for chiral oscillation of Majorana neutrinos based on quantum field theory. Since the Hamiltonian under the Majorana mass term does not conserve lepton number, the eigenstates of lepton number change continuously over time. Therefore, the transition amplitude is described by the inner product of the eigenstates of lepton number at the time of the neutrino production and the detection. With the Bogoliubov transformation, we successfully relates the lepton number eigenstates at different times. This method enables us to understand the time variation of lepton number induced by chiral oscillations in terms of transition probabilities. We also present the physical picture that emerges through the Bogoliubov transformation. © 2025, CC BY.

关键词： Hamiltonians

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Measurement of H6 Ground State Energy in an Electron Scattering Experiment at MAMI-A1

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Physical Review Letters 2025年第16期134卷 162501-162501页

作者： Tianhao Shao Jinhui Chen Josef Pochodzalla Patrick Achenbach Mirco Christmann Michael O. Distler Luca Doria Anselm Esser Julian Geratz Christian Helmel Matthias Hoek Ryoko Kino Pascal Klag Yu-Gang Ma David Markus Harald Merkel Miha Mihovilovič Ulrich Müller Sho Nagao Satoshi N. Nakamura Kotaro Nishi Ken Nishida Fumiya Oura Jonas Pätschke Björn Sören Schlimme Concettina Sfienti Daniel Steger Marcell Steinen Michaela Thiel Andrzej Wilczek Luca Wilhelm Institut für Kernphysik Johannes Gutenburg-Universität D-55099 Mainz Germany Key Laboratory of Nuclear Physics and Ion-beam Application (MOE) Institute of Modern Physics Fudan University 200433 Shanghai China Shanghai Research Center for Theoretical Nuclear Physics NSFC and Fudan University 200433 Shanghai China Helmholtz-Institut Mainz Johannes Gutenberg-Universität Mainz 55099 Mainz Germany PRISMA Cluster of Excellence Johannes Gutenberg-Universität Mainz 55099 Mainz Germany Graduate School of Science Tohoku University Sendai Miyagi 980-8578 Japan Graduate Program on Physics for the Universe (GP-PU) Tohoku University Sendai Miyagi 980-8578 Japan Department of Physics Graduate School of Science The University of Tokyo 113-0033 Tokyo Japan Graduate School of Science Tohoku University Miyagi 980-8578 Sendai Japan Institute of Physics University of Silesia in Katowice 41-500 Chorzów Poland

For the first time the neutron-rich hydrogen isotope H6 was produced in an electron scattering experiment in the reaction Li7(e,e′pπ+)6H using the spectrometer facility of the A1 Collaboration at the Mainz Microtron accelerator. By measuring the triple coincidence between the scattered electron, the produced proton, and π+, the missing mass spectrum of H6 was obtained. A clear peak above H3+n+n+n energy threshold was seen resulting in a ground state energy of H6 at 2.3±0.5(stat.)±0.4(syst.) MeV with a width of 1.9±1.0(stat.)±0.4(syst.) MeV. This Letter challenges the understandings of multinucleon interactions and presents a new method to study light neutron-rich nuclei with electron scattering experiments.

关键词： Ground state

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Neutrinos and Gamma Rays from Beta Decays in an Active Galactic Nucleus NGC 1068 Jet

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Physical Review Letters 2025年第15期134卷 151005-151005页

作者： Koichiro Yasuda Nobuyuki Sakai Yoshiyuki Inoue Alexander Kusenko Department of Physics and Astronomy University of California Los Angeles Los Angeles California 90095-1547 USA Department of Earth and Space Science Graduate School of Science Osaka University Toyonaka Osaka 560-0043 Japan Interdisciplinary Theoretical & Mathematical Science Program (iTHEMS) RIKEN 2-1 Hirosawa Saitama 351-0198 Japan Kavli Institute for the Physics and Mathematics of the Universe (WPI) UTIAS The University of Tokyo Kashiwa Chiba 277-8583 Japan

We show that TeV neutrinos and high-energy gamma rays detected from the nearby active galaxy NGC 1068 can simultaneously be explained in a model based on the beta decays of neutrons produced in the photodisintegration of He4 nuclei on ultraviolet photons in the jet. The photodisintegration of nuclei occurs at energies above several PeV, which explains the 1–100 TeV energies of the observed neutrinos. The TeV gamma-ray flux accompanying the beta decays is expected to be much lower than the neutrino flux, which agrees with the observations of NGC 1068 showing a gamma-ray deficit as compared to the expectations from proton-photon interactions. Furthermore, the synchrotron and inverse Compton gamma-ray flux associated with protons’ Bethe-Heitler pair production and the photopion processes in the jet can be consistent with the observed gamma-ray flux at GeV energies for a plausible range of magnetic fields of jets. This scenario, combining beta decay and Bethe-Heitler, can be applied to other jet Seyfert galaxies such as NGC 4151. Future measurements of the neutrino flavor ratio can help confirm the beta-decay origin of the observed neutrinos.

关键词： Active Galactic Nuclei

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Signature of hadron-quark crossover in binary-neutron-star mergers

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Physical Review D 2025年第6期111卷 063054-063054页

作者： Yuki Fujimoto Kenji Fukushima Kenta Hotokezaka Koutarou Kyutoku Institute for Nuclear Theory University of Washington Box 351550 Seattle Washington 98195 USA Department of Physics The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-0033 Japan Research Center for the Early Universe (RESCEU) Graduate School of Science The University of Tokyo Tokyo 113-0033 Japan Department of Physics Graduate School of Science Chiba University Chiba 263-8522 Japan Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS) RIKEN Wako Saitama 351-0198 Japan

We study observational signatures of the hadron-quark crossover in binary-neutron-star mergers by numerical-relativity simulations with various mass configurations. We employ two equations of state (EoSs) for matter consistent with inference from the observational data. In the crossover scenario the EoS is softened in a density realized in binary-neutron-star mergers and is smoothly continued to quark matter. In the phase transition scenario without crossover, the EoS remains stiff and a first-order phase transition takes place in a density out of reach of mergers. A GW170817-like system forms a remnant massive neutron star in both scenarios, and it collapses into a black hole only in the crossover scenario due to the softening while gravitational-wave emission is strong. This difference is clearly reflected in the sudden shutdown of gravitational waves. For a given EoS, the lifetime of the merger remnant is determined primarily by the total mass of the system. Identifying these features in a variety of future events with the next generation of ground-based gravitational-wave detectors will enable us to clarify details of hadron-quark transition. The mass of the accretion disk surrounding the remnant black hole is affected not only by the lifetime of the remnant but also by the mass ratio of the system. Electromagnetic emission associated with the disk outflow will also be useful for detailed investigation of the hadron-quark transition.

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Recent advances in silver oxide-based superconductors: characterization, challenges and theoretical progress

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Journal of the Korean Ceramic Society 2025年 1-20页

作者： Duma, Tulus Na Humaidi, Syahrul Imaduddin, Agung Kechik, Mohd. Mustafa Awang Miryala, Muralidhar Postgraduate Program (Physics) FMIPA Universitas Sumatera Utara Medan Indonesia Research Center for Advanced Materials-National Research and Innovation Agency (BRIN) Tangerang Selatan Indonesia Superconductor and Thin Films Laboratory Department of Physics Faculty of Science Universiti Putra Malaysia UPM Serdang Selangor Darul Ehsan Malaysia Materials for Energy and Environmental Laboratory Superconducting Materials Group Graduate School of Science and Engineering Shibaura Institute of Technology Tokyo Japan

Recent advancements in superconductivity have generated significant interest in silver oxide-based materials due to their potential for unconventional superconducting mechanisms and unique electronic properties. This review provides a comprehensive analysis of recent progress in the synthesis, characterization and theoretical modeling of these superconductors. Experimental techniques such as hydrothermal, sol-gel and solid-state methods are critically assessed, highlighting key challenges in achieving the desired composition, crystal structure and phase purity. Additionally, the integration of density functional theory (DFT) and machine learning (ML) has emerged as a powerful approach for predicting novel silver oxide superconductors with improved properties, with recent models identifying candidate materials with potential $${T}_{c}$$ values exceeding 50 K. Despite these promising developments, significant challenges remain, particularly concerning large-scale production, material stability and superconducting phase optimization. By integrating experimental insights with computational advancements, this review outlines key directions for future research, aiming to accelerate the discovery and practical implementation of silver oxide-based superconductors for energy, quantum computing and electronic applications.

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Mo-terminated edges in two-dimensional molybdenum disulfide for site-specific hydrolysis and DNA cleavage

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Materials Today 2025年 86卷 162-171页

作者： Wang, Cong Wu, Menghan Li, Muqing Zhao, Yingcan Zhao, Mingchuang Zhang, Yunhao Bai, Yichao Gao, Jianxiang Wang, Xiaoxia Tian, Xilin Zhang, Han Chang, Liang Zou, Xiaolong Liu, Bilu Kang, Feiyu Terrones, Mauricio Lei, Yu Institute of Materials Research Shenzhen Key Laboratory of Advanced Layered Materials for Value-added Applications Guangdong Provincial Key Laboratory of Thermal Management Engineering and Materials & Center of Double Helix Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen518055 China Institute of Materials Research & Shenzhen Geim Graphene Center Shenzhen Key Laboratory of Advanced Layered Materials for Value-added Applications Tsinghua-Berkeley Shenzhen Institute and Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen518055 China Environmental Science Program Department of Life Sciences Beijing Normal University-Hong Kong Baptist University United International College Guangdong519087 China Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen518055 China Department of Physics Department of Chemistry Department of Materials Sciences Center for 2-Dimensional and Layered Materials The Pennsylvania State University University ParkPA16802 United States International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale Optoelectronics Shenzhen University Shenzhen518060 China

The hydrolysis of DNA serves as the foundational principle for gene engineering that enable precise gene cleavage at the molecular level. This process typically occurs in biological nucleases, which exhibit nucleobase-selective and catalytic hydrolysis capabilities rarely replicated in abiotic nanomaterials. Here, we demonstrate that molybdenum-terminated (Mo-terminated) edges of molybdenum disulfide (MoS2) possess the unique ability to abstract a proton (H+) from water molecules, thereby facilitating catalytic hydrolysis reactions that cleave the phosphodiester bonds in DNA through the action of hydroxide ions. The enhanced proton absorption at Mo-terminated edges of MoS2 significantly reduces the activation energy required for the DNA hydrolysis reaction. Furthermore, the favorable interaction between the Mo-terminated edges and thymine nucleobases promotes both charge transfer and P-O bond cleavage, enabling targeted DNA hydrolysis at 'TTTTTTT' sequences under dark conditions. This discovery underscores the potential of MoS2 as a stable, efficient nanosystem for precise genetic editing, heralding advanced applications in the field of gene engineering. © 2025 The Author(s)

关键词： Activation energy

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Robustness of contextuality under different types of noise as quantifiers for parity-oblivious multiplexing tasks

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Physical Review A 2025年第2期111卷 022217-022217页

作者： Amanda M. Fonseca Vinicius P. Rossi Roberto D. Baldijão John H. Selby Ana Belén Sainz Institute of Physics University of São Paulo 05508-090 São Paulo São Paulo Brazil International Centre for Theory of Quantum Technologies University of Gdańsk 80-309 Gdańsk Poland Theoretical Sciences Visiting Program Okinawa Institute of Science and Technology Graduate University Onna Okinawa 904-0495 Japan Basic Research Community for Physics e.V. Germany

Generalized contextuality is the notion of nonclassicality powering up a myriad of quantum tasks, among which is the celebrated case of a two-party information processing task where classical information is compressed in a quantum channel, the parity-oblivious multiplexing (POM) task. The success rate is the standard quantifier of resourcefulness for this task, while robustness-based quantifiers are as operationally motivated and have known general properties. In this work we leverage analytical and numerical tools to estimate robustness of contextuality in POM scenarios under different types of noise. We conclude that for the 3-to-1 case, robustness of contextuality to depolarization as well as a minimization of robustness of contextuality to dephasing over all bases are good quantifiers for the nonclassical advantage of this scenario. Moreover, we obtain a general relation between robustness of contextuality to depolarization and the success rate in any n-to-1 POM scenario and show how it can be used to bound the number of bits encoded in this task.

关键词： Quantum channel

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Polaronic neutron in dilute α matter: A p-wave Bose polaron

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Physical Review C 2025年第2期111卷 025802-025802页

作者： Hiroyuki Tajima Hajime Moriya Tomoya Naito Wataru Horiuchi Eiji Nakano Kei Iida Department of Physics Graduate School of Science The University of Tokyo Tokyo 113-0033 Japan RIKEN Nishina Center Wako 351-0198 Japan Research Center for Nuclear Physics Osaka University Ibaraki 567-0047 Japan Interdisciplinary Theoretical and Mathematical Science Program (iTHEMS) RIKEN Wako 351-0198 Japan Department of Physics Osaka Metropolitan University Osaka 558-8585 Japan Nambu Yoichiro Institute of Theoretical and Experimental Physics (NITEP) Osaka Metropolitan University Osaka 558-8585 Japan Department of Physics Hokkaido University Sapporo 060-0810 Japan Department of Mathematics and Physics Kochi University Kochi 780-8520 Japan

We theoretically investigate quasiparticle properties of a neutron immersed in an alpha condensate, which is one of the possible states of dilute symmetric nuclear matter. The resonant p-wave neutron-alpha scattering, which plays a crucial role in forming halo nuclei, is considered. This system is similar to a Bose polaron near the p-wave Feshbach resonance that can be realized in cold-atomic experiments. Calculating the self-energy within the field-theoretical approach, we give an analytical formula for the effective mass of a polaronic neutron as a function of alpha condensation density. Moreover, two adjacent neutrons in a medium, each of which behaves like a stable polaron having an enhanced effective mass, can form a bound dineutron, with the help of S01 neutron-neutron attraction. This is in contrast to the case of the vacuum, where a dineutron is known to be unbound. Our result is useful for understanding many-body physics in astrophysical environments as well as the formation of multinucleon clusters in neutron-halo nuclei.

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Statistical biases in parameterized searches for gravitational-wave polarizations

arXiv

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arXiv 2025年

作者： Imafuku, Hayato Takeda, Hiroki Nishizawa, Atsushi Watarai, Daiki Cannon, Kipp Graduate School of Science The University of Tokyo Tokyo113-0033 Japan Graduate School of Science The University of Tokyo Tokyo113-0033 Japan The Hakubi Center for Advanced Research Kyoto University Yoshida Ushinomiyacho Sakyo-ku Kyoto606-8501 Japan Department of Physics Kyoto University Kyoto606-8502 Japan Physis Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima Higashi-Hiroshima739-8526 Japan Astrophysical Science Center Hiroshima University Hiroshima Higashi-Hiroshima739-8526 Japan

In tests of gravity using gravitational waves (GWs), GW events analyzed are often selected based on specific criteria, particularly the signal-to-noise ratio (SNR). However, such event selection can introduce bias into parameter estimation unless the selection effect is appropriately taken into account in the analysis. In this paper, we investigate how event selection with certain prior information affects parameter inference within the scalar-tensor polarization framework, focusing on the measurement of the scalar mode amplitude parameters. We find that for the Tensor+Scalar(dipole) model, the amplitude of the scalar dipole radiation is overestimated when its true value is nonzero while there is no false deviation in the absence of the scalar mode. The same bias is expected to occur also for the Tensor+Scalar(quadrupole) model. However, error typically exceeds the bias as the scalar quadrupole mode is difficult to be distinguished from the tensor mode. © 2025, CC BY.

关键词： Signal to noise ratio

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