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Enhanced accuracy of isotope-shift measurements of Yb+ 369- and 935-nm transitions via sympathetic cooling

Physical Review A 2025年第3期111卷 033101-033101页

作者： Jize Han Ying Zheng Yanmei Yu Jiguang Li Zhiguo Huang Jingwei Wen Ling Qian Lijun Wang Department of Precision Instrument Tsinghua University Beijing 100084 China China Mobile (Suzhou) Software Technology Company Ltd. Suzhou 215163 China Department of Physics Tsinghua University Beijing 100084 China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China Institute of Applied Physics and Computational Mathematics Beijing 100088 China

We report enhanced accuracy in isotope-shift (IS) measurement using sympathetic cooling, demonstrated with Yb+170,172,174,176 transitions at 369 and 935 nm. Considering only type-A uncertainties, sympathetic cooling achieves 30- and 200-fold improvements in IS measurement accuracy at 369 and 935 nm compared with previous single-ion results. Our measurements remain the most accurate to date including type-B uncertainties. King-plot analysis yields model-independent IS factors for these transitions [F369=−12.3(8) GHz/fm2, K369=−1800(1400) GHz u, F935=30.7(2.0) GHz/fm2, and K935=12900(3000) GHz u] and their ratio [F935F369=−2.498(4)] along with K935−K369F935F369=8410(90) GHz u, representing a 17-fold improvement. More reliable nuclear charge radii for Yb170–174,176 are also determined with an accuracy of 0.01 fm2. This paper complements collinear laser spectroscopy, introduces a robust approach for researching unstable isotopes, and supports applications of sympathetic cooling in trapped-ion quantum computers and quantum frequency standards.

关键词： Quantum computers

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Nodal points, lines, and surfaces, and topological surface states in superconductor NiBi3

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Physical Review B 2025年第9期111卷 094508-094508页

作者： Jie Zhang Kai-Yue Jiang Shu-Xiang Qiao Peng-Cheng Xiao Na Jiao Ping Zhang Hong-Yan Lu Qi-Feng Liang School of Physics and Physical Engineering Qufu Normal University Qufu 273165 China Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices High Magnetic Field Laboratory HFIPS Chinese Academy of Sciences Hefei Anhui 230031 China Institute of Applied Physics and Computational Mathematics Beijing 100088 China Department of Physics Shaoxing University Shaoxing 312000 China

Despite the numerous reports on the time-honored superconductor NiBi3, theoretical investigations remain limited, particularly regarding the impact of spin-orbit coupling (SOC). Based on first-principles calculations, the electronic topology of NiBi3 is mainly studied herein. Nodal loops which intersect to form a nodal chain structure are enclosed by two valence bands, and they are fully gapped by SOC. The full gap contains topological surface states defined by a Z2 topological invariant, while for the top valence band and bottom conduction band, a three-dimensional massless Dirac point at Γ is produced by the two bands with SOC. In addition, nodal surfaces which prevalently appear in the band structure without SOC are present on the entire Brillouin zone surface, and SOC only partially gaps them, thus leading to nodal lines unaffected by SOC. Type-I and type-II fermions, which are distinguished by the tilt of cones, are shown to coexist in the bulk bands. Furthermore, two Rashba-split bands are found on the (100) surface, whose inner and outer Fermi circles share the same spin polarization direction. Finally, our analysis reveals that the superconductivity of NiBi3 primarily originates from the p orbitals of Bi and d orbitals of Ni coupling with the vibration modes of Bi. The rich topological features identified in this study suggest that NiBi3 holds significant potential for realizations of topological superconductivity and other exotic phenomena.

关键词： Topology

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Structural properties of hyperuniform Voronoi networks

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Physical Review E 2025年第3期111卷 034123-034123页

作者： Eli Newby Wenlong Shi Yang Jiao Reka Albert Salvatore Torquato Department of Physics Pennsylvania State University University Park Pennsylvania 16802 USA Materials Science and Engineering Arizona State University Tempe Arizona 85287 USA Department of Physics Arizona State University Tempe Arizona 85287 USA Department of Chemistry Princeton University Princeton New Jersey 08544 USA Department of Physics Princeton University Princeton New Jersey 08544 USA Princeton Institute of Materials Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

Disordered hyperuniform many-particle systems are recently discovered exotic states of matter, characterized by the complete suppression of normalized infinite-wavelength density fluctuations, as in perfect crystals, while lacking conventional long-range order, as in liquids and glasses. In this work, we begin a program to quantify the structural properties of nonhyperuniform and hyperuniform networks. In particular, large two-dimensional (2D) Voronoi networks (graphs) containing approximately 10,000 nodes are created from a variety of different point configurations, including the antihyperuniform hyperplane intersection process (HIP), nonhyperuniform Poisson process, nonhyperuniform random sequential addition (RSA) saturated packing, and both non-stealthy and stealthy hyperuniform point processes. We carry out an extensive study of the Voronoi-cell area distribution of each of the networks by determining multiple metrics that characterize the distribution, including their average areas and corresponding variances as well as higher-order cumulants (i.e., skewness γ1 and excess kurtosis γ2). We show that the HIP distribution is far from Gaussian, as evidenced by a high skewness (γ1=3.16) and large positive excess kurtosis (γ2=16.2). The Poisson (with γ1=1.07 and γ2=1.79) and non-stealthy hyperuniform (with γ1=0.257 and γ2=0.0217) distributions are Gaussian-like distributions, since they exhibit a small but positive skewness and excess kurtosis. The RSA (with γ1=0.450 and γ2=−0.0384) and the highest stealthy hyperuniform distributions (with γ1=0.0272 and γ2=−0.0626) are also non-Gaussian because of their low skewness and negative excess kurtosis, which is diametrically opposite of the non-Gaussian behavior of the HIP. The fact that the cell-area distributions of large, finite-sized RSA and stealthy hyperuniform networks (e.g., with N≈10,000 nodes) are narrower, have larger peaks, and smaller tails than a Gaussian distribution implies that in the thermodynamic limit th

关键词： Gaussian distribution

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Nonmonotonic superconductivity, nontrivial band topology, and electride state in a beryllene system

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Physical Review B 2025年第9期111卷 094501-094501页

作者： Kai-Yue Jiang Yu-Lin Han Shu-Xiang Qiao Ping Zhang Qiang-Hua Wang C. S. Ting Hong-Yan Lu School of Physics and Physical Engineering Qufu Normal University Qufu 273165 China Institute of Applied Physics and Computational Mathematics Beijing 100088 China National Laboratory of Solid State Microstructures & School of Physics Nanjing University Nanjing 210093 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China Texas Center for Superconductivity and Department of Physics University of Houston Houston Texas 77204 USA

Controlling the layer number of superconducting (SC) units can effectively modulate superconductivity of layered materials. Here, through first-principles calculations, the electronic and SC properties of beryllenes have been systematically investigated. The SC transition temperature Tc shows nonmonotonic behavior, with maximum of 8.5 K for AB-stacking and 6.4 K for ABC-stacking trilayer beryllenes. Notably, these Tc are two orders of magnitude higher than 0.026 K of bulk beryllium attributed to the enhanced electron-phonon coupling from phonon softening of surface Be and the increased density of states at the Fermi level. Additionally, several beryllenes exhibit nontrivial band topology, providing platforms for studying topological superconductivity. Moreover, all the beryllenes show the electride nature due to interstitial anionic electrons. These results highlight the importance of reduced dimensionality on physical properties and offer the first example of a single-element material with trilayer SC units achieving the highest Tc.

关键词： Topology

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Effective Transport and Mechanical Properties of Two-Phase Materials Across the Order-Disorder Spectrum

SSRN

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SSRN 2025年

作者： Skolnick, Murray Torquato, Salvatore Department of Chemistry Princeton University PrincetonNJ08544 United States Department of Physics Princeton University PrincetonNJ08544 United States Princeton Institute of Materials Princeton University PrincetonNJ08544 United States Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States

Two-phase heterogeneous materials arise in a plethora of natural and synthetic situations, such as alloys, composites, geological media, complex fluids, and biological media, exhibit a wide-variety of microstructures, and thus display a broad-spectrum of effective physical properties. Elucidating how microstructural details (e.g., specific surface, phase volume fractions, geometries, and topologies) influence two-phase materials’ effective transport and mechanical properties enhances our fundamental understanding of microstructure-property relationships, and is of great practical use in the design of structural and functional materials. Here, we compute the three-point microstructural parameters ζ2 and η2 for phase 2 to evaluate bounds and accurate approximation formulas on the effective thermal/electrical conductivities σe as well as the bulk Ke and shear Ge moduli of a wide class of disordered 2D and 3D material microstructures;including various dispersions of hard and penetrable particles, certain amorphous dispersions, and networks. These parameters are determined using a Monte Carlo integration scheme that incorporates certain algorithmic enhancements that improve upon the accuracy and performance of previous methods. Our results reveal that ζ2 and η2 are sensitive to the phase-connectedness properties of microstructures. Using numerical simulations and rigorous approximations that incorporate ζ2 and η2, we show that certain disordered microstructures nearly realize the Hashin-Shtrikman lower and upper bounds on σe, Ke, and Ge across volume-fractions. We also describe how our algorithm can be used in inverse methodologies to realize ordered and disordered materials with desirable effective physical properties by targeting specific values of ζ2 and η2, and hence aid in materials by design. © 2025, The Authors. All rights reserved.

关键词： Inverse problems

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Photodissociation dynamics of SiH+: Rovibrationally resolved Feshbach resonances mediated by coupled excited states in the ultraviolet region

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Physical Review A 2025年第1期111卷 013118-013118页

作者： Yu Kun Yang Xing Guang Su Kun Wang Yongjun Cheng Quan Wei Nan Zeqing Wang Danny L. Yeager Yong Wu Jian Guo Wang School of Physics Henan Normal University Xinxiang 453000 China Institute of Environmental Science Shanxi University Taiyuan 030006 China School of Physics and Information Technology Shaanxi Normal University Xi'an 710119 China Department of Physics Renmin University of China Beijing 100872 China Department of Chemistry Texas A&M University College Station Texas 77843 USA Institute of Applied Physics and Computational Mathematics P.O. Box 8009 Beijing 100088 China

Photodissociation cross sections of SiH+ have been explored within the uncoupled theoretical framework, notably in the work of Stancil et al. [Astrophys. J. 486, 574 (1997)]. However, in the SiH+ system, there are significant nonadiabatic interactions between the 31Π and 41Π states, which substantially affect the photodissociation process, particularly in the region between the Lyman α line and the Lyman limit. These nonadiabatic couplings give rise to numerous Feshbach resonances, significantly altering the final photodissociation cross sections. The present study highlights the critical importance of incorporating nonadiabatic electronic couplings to achieve accurate cross-section calculations. The results substantially enrich the data set on small molecular structures and spectra in interstellar clouds, providing essential theoretical support for future experimental investigations and for the modeling and analysis of stellar spectra. Additionally, this work offers key insights into the underlying physical mechanisms by which Feshbach resonances modulate line shapes in coupled photodissociation scattering cross sections.

关键词： Photodissociation

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Nonlinear bubble behaviours of compressible Rayleigh–Taylor instability with isothermal stratification in cylindrical geometry

arXiv

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arXiv 2025年

作者： Yuan, Ming Zhao, Zhiye Liu, Luoqin Wang, Pei Liu, Nan-Sheng Lu, Xi-Yun Department of Modern Mechanics University of Science and Technology of China Anhui Hefei230026 China Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and Technology Hong Kong Institute of Applied Physics and Computational Mathematics Beijing100094 China

Nonlinear evolutions of two-dimensional single-mode compressible Rayleigh–Taylor instability (RTI) with isothermal stratification are investigated in cylindrical geometry via direct numerical simulation for different Atwood numbers (AT = 0.1 − 0.9) and Mach numbers (Ma = 0.1 − 0.9). It is found that the nonlinear bubble growth involves the effects of density stratification, vorticity accumulation and flow compressibility and shows considerable differences between convergent (acceleration acting radially inward) and divergent (acceleration acting radially outward) cases. Specifically, the density stratification leads to non-acceleration at low AT and high Ma. The accelerations in convergent cases are dominated by vorticity accumulation at low AT and low Ma and by flow compressibility at high AT and high Ma whereas the accelerations in divergent cases are purely induced by flow compressibility at high AT and high Ma. Based on the nonlinear theory of incompressible cylindrical RTI with uniform-density background (Zhao et al., J. Fluid Mech., vol. 900, 2020, A24), an improved model is proposed by taking the density variation, vorticity accumulation and flow compressibility into consideration. This model is verified by numerical results and well reproduces the bubble evolution for different AT and Ma from linear to highly nonlinear regimes. © 2025, CC BY.

关键词： Vorticity

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Inferring System and Optimal Control Parameters of Closed-Loop Systems from Partial Observations

arXiv

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arXiv 2025年

作者： Geadah, Victor Arbelaiz, Juncal Ritz, Harrison Daw, Nathaniel D. Cohen, Jonathan D. Pillow, Jonathan W. Program in Applied and Computational Mathematics Princeton University PrincetonNJ United States Department of Mechanical and Aerospace Engineering Princeton University PrincetonNJ United States Princeton Neuroscience Institute Princeton University PrincetonNJ United States

We consider the joint problem of system identification and inverse optimal control for discrete-time stochastic Linear Quadratic Regulators. We analyze finite and infinite time horizons in a partially observed setting, where the state is observed noisily. To recover closed-loop system parameters, we develop inference methods based on probabilistic state-space model (SSM) techniques. First, we show that the system parameters exhibit non-identifiability in the infinite-horizon from closed-loop measurements, and we provide exact and numerical methods to disentangle the parameters. Second, to improve parameter identifiability, we show that we can further enhance recovery by either (1) incorporating additional partial measurements of the control signals or (2) moving to the finite-horizon setting. We further illustrate the performance of our methodology through numerical examples. © 2025, CC BY.

关键词： Stochastic systems

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Resonant tunneling and quantum fluctuation in a driven triple-well system

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Chinese physics B 2010年第2期19卷 39-46页

作者：卢伟涛王顺金张华 Department of Physics Sichuan University Institute of Applied Physics and Computational Mathematics

The influence of parameters such as the strength and frequency of a periodic driving force on the tunneling dynamics is investigated in a symmetric triple-well potential. It is shown that for some special values of the parameters, tunneling could be enhanced considerably or suppressed completely. Quantum fluctuation during the tunneling is discussed as well and the numerical results are presented and analysed by virtue of Floquet formalism.

关键词： triple-well potential non-resonant tunneling resonant tunneling Floquet theorem quantum fluctuation

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Zero dielectric constant limit to the non-isentropic compressible Euler-Maxwell system

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Science China mathematics 2015年第1期58卷 61-76页

作者： JIANG Song LI FuCai Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Department of Mathematics Nanjing University

We investigate the zero dielectric constant limit to the non-isentropic compressible Euler-Maxwell *** justify this singular limit rigorously in the framework of smooth solutions and obtain the nonisentropic compressi... 详细信息

关键词： non-isentropic compressible Euler-Maxwell system non-isentropic compressible magnetohydro-dynamic equations zero dielectric constant limit

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