bluuebunny/crossref_metadata_2025 huggingface dataset:
On-machine separation and compensation of target mirror’s surface shape errors in multidimensional interferometric measurement system
Authors: Zhang Zuyang , Huang Qiangxian , Lu Jun , Li Hongli , Cheng Rongjun , Zhang Liansheng
Published: January 2025

In multi-dimensional nanopositioning and nanomeasuring devices, interference measurement is widely used. The three-dimensional (3D) target mirror serves as the spatial reference plane to achieve multidimensional interference measurements. However, the surface shape errors of the target mirror are superimposed on the geometric dimensions of the measured workpiece, which limits the system’s overall measurement accuracy. This paper proposes a method for on-machine separation and compensation of the target mirror’s surface shape errors based on the micro–nano-coordinate measuring machine (MNCMM) that employs interference measurement. This method provides the model for the separation and compensation of the surface shape errors. The MNCMM employs a home-made resonant probe and a reference flat crystal to achieve the separation experiment. Subsequently, an interpolation algorithm is used to compensate for the surface shape errors at any point in space according to the compensation model. By comparing the flatness measurement results of a standard flat crystal with a flatness of 50 nm before and after compensation, the flatness is reduced from 175 to 77 nm. It demonstrates the reliability of the method. This method can be widely applied to on-machine compensation for surface shape errors in multidimensional interference measurement systems.
Exceptionally large fluctuations in orientational order: The lessons of large-deviation theory for liquid crystalline systems
Authors: Mainas Eleftherios , Stratt Richard M.
Published: January 2025

How condensed-matter simulations depend on the number of molecules being simulated (N) is sometimes itself a valuable piece of information. Liquid crystals provide a case in point. Light scattering and 2d-IR experiments on isotropic-phase samples display increasingly large orientational fluctuations (“pseudo-nematic domains”) as the samples approach their nematic phase. The growing length scale of those locally ordered domains is readily seen in simulation as an ever-slower convergence of the distribution of orientational order parameters with N. But the rare-event character and exceptionally slow time scales of the largest fluctuations make them difficult to sample accurately. We show in this paper how taking a large-deviation-theory perspective enables us to leverage simulation-derived information more effectively. A key insight of the theory is that finding quantities such as orientational order parameters (extensive variables) is completely equivalent to deducing the conjugate (intensive) thermodynamic field required to equilibrate that amount of order—and that knowing the relationship between the two (the “equation of state”) can easily be turned into knowing the relative free energy of that degree of order. A variety of well-known thermodynamic integration strategies are already founded on this idea, but instead of applying an artificially imposed external field, we use a priori statistical mechanical insights into the small and large-field limits to construct a simulation-guided, interpolated, equation of state. The free energies that result mostly need information from the most probable configurations, making the simulation process far more efficient than waiting for (or artificially generating) large fluctuations.
Pearling of cylindrical vesicles induced by acoustofluidics
Authors: Wang Shenggeng , Wang Zhenyu , Zhou Qingli , Tang Guoping , Yang Zengtao , Zhu Xinjian
Published: January 2025

The mechanical transformation of lipid membranes in biological structures plays a key role in the morphogenesis of cells and tissues. However, the mechanism by which active forces influence the shape transition of lipid vesicles remains unclear. Herein, we propose an acoustofluidics method to deform the cylindrical vesicles. The study combines theoretical and experimental approaches to investigate the shape behavior of cylindrical vesicles in an acoustic field. Analytical equations are established to describe the manipulation of radial deformation and elongation in cylindrical vesicles. Pearling of these vesicles is induced by the competition between membrane tension and drag force. In conditions of weak drag force, cylindrical vesicles under tension minimize their free energy through surface fluctuations, resulting in a beaded structure. This transformation creates a beads-on-a-string formation, consisting of uniformly sized spherical vesicles connected by fine lipid nanotubes. The findings offer a non-contact method to enhance the understanding and control of the shape dynamics in membranes within active matter systems.
The mechanism about the flow characteristics of dimples on the highly loaded compressor blade induced by their geometry and flow conditions
Authors: Lu Huawei , Wang Long , Li Shanshan , Liu Jun , Guo Shuang , Peng Benli
Published: January 2025

To clarify the flow control mechanism of the dimple surface and its influencing factors, this paper arranged cavity structures on the suction surface of a highly loaded compressor cascade. The Reynolds-averaged Navier–Stokes equations were utilized to calculate the impact of the geometric structure and inlet conditions of a dimple on the flow characteristics and flow control effect on the dimple surface. Additionally, the stress-blended eddy simulation was employed to compute the unsteady characteristics of the dimple vortex. By using the Liutex vortex determination criterion, flow regimes (diffuser-confuser, horseshoe vortex, and tornado-like vortex) and vortex axis morphologies (I-axis, C-axis, and V-axis) were identified. The flow regime diagram based on the Reynolds number and depth-to-diameter ratio was drawn, and boundary formulas for each flow pattern were provided. The vortex shedding frequency (1900–2300 Hz) and the main stream impingement frequency (5400–8154 Hz) for the cavity with a relative depth of 0.0625 were detected. By quantifying the vortex intensity coefficient and the increments of the inlet and outlet parameters of the cavity, the vortex and flow control capabilities were assessed. The results revealed that the peak vortex intensity occurred in the depth-to-diameter ratio range of 0.2–0.5, and the increase in dimple depth can improve the vortex intensity and delay the depth-diameter ratio corresponding to the peak value. The increment of turbulent kinetic energy and flow velocity at the outlet of the dimple to the flow field was proportional to the depth and inversely proportional to the depth-diameter ratio.
Thermodynamics of nucleosome breathing and positioning
Authors: Hungyo Kharerin , Audit Benjamin , Vaillant Cédric , Morozov Alexandre V.
Published: January 2025

Nucleosomes are fundamental units of chromatin in which a length of genomic DNA is wrapped around a histone octamer spool in a left-handed superhelix. Large-scale nucleosome maps show a wide distribution of DNA wrapping lengths, which in some cases are tens of base pairs (bp) shorter than the 147 bp canonical wrapping length observed in nucleosome crystal structures. Here, we develop a thermodynamic model that assumes a constant free energy cost of unwrapping a nucleosomal bp. Our model also incorporates linker DNA—short DNA segments between neighboring nucleosomes imposed by the folding of nucleosome arrays into chromatin fibers and other higher-order chromatin structures. We use this model to study nucleosome positioning and occupancy in the presence of nucleosome “breathing”—partial unwrapping and rewrapping of nucleosomal DNA due to interactions with the neighboring particles. We find that, as the unwrapping cost per bp and the chemical potential are varied, the nucleosome arrays are characterized by three distinct states, with low, intermediate, and high densities. The transition between the latter two states proceeds through an equiprobable state in which all nucleosome wrapping lengths are equally likely. We study the equiprobable state theoretically using a mean-field approach, obtaining an excellent agreement with numerical simulations. Finally, we use our model to reproduce S. cerevisiae nucleosome occupancy profiles observed in the vicinity of transcription start sites, as well as genome-wide distributions of nucleosome wrapping lengths. Overall, our results highlight the key role of partial nucleosome unwrapping in shaping the genome-wide patterns of nucleosome positioning and occupancy.
Double shock solutions for non-ideal detonations with endothermic reaction step
Authors: Semenko Roman , Raufov Humoyun
Published: January 2025

We analyzed the problem of one-dimensional steady detonation wave with momentum losses caused by the presence of solid inert objects on the path of the wave. The process is modeled by reactive Euler equations with two-step kinetics with exothermic first step and endothermic second step. We showed that the steady-state solutions exist for the whole range of detonation wave velocities D from the ideal detonation velocity down to the speed of sound in the fresh mixture, and that these solutions could be divided in three categories. The solutions with high detonation wave velocities retain the typical structure of self-sustained detonation wave with embedded Chapman–Jouguet point. The solutions with very low detonation wave velocities remain fully subsonic relative to the detonation front, which make them not self-sustained. Finally, the solutions with detonation velocity values between two aforementioned cases contain the second shock wave behind the detonation front. While first two types of steady-state solutions also exist in the problems with one-step chemistry, the last type emerges only at the presence of the endothermic reaction step.
Fragmented charged domain wall below the tetragonal-orthorhombic phase transition in BaTiO3
Authors: Bednyakov Petr S. , Rafalovskyi Iegor , Hlinka Jiří
Published: January 2025

Ferroelectric charged domain walls are known for their high electrical conductivity, making them promising candidates for modern electronics. A remarkably high conductivity and nominal charge density has been found in the head-to-head ferroelastic domain wall of tetragonal barium titanate. Conductivity of this domain wall decreases by several orders of magnitude when the temperature drops down below about 5 °C when the tetragonal phase transforms to the orthorhombic one. We explored the evolution of these ferroelectric charged domain walls in BaTiO3 crystals, while they undergo this phase transition by in situ optical microscopy. Our results reveal that, below the phase transition, the domains adjacent to charge domain walls become twinned, and the head-to-head charged domain wall transforms into a superdomain wall, which is broken into alternating micrometer-scale segments with and without the excess bound charge. Since the macroscopic conductive channel along such fragmented superdomain wall is disrupted, these observations explain the observed loss of the domain wall conductivity below the phase transition.
Enhancing the Goman–Khrabrov dynamic stall model through flow delay analysis
Authors: Zheng Boda , Yao Weigang , Xu Min
Published: January 2025

The complete dynamic stall process encompasses a series of complex developmental stages, such as flow separation, leading edge vortex shedding, and reattachment. Unlike static stall, dynamic stall exhibits hysteresis, rendering phenomenological models as complex nonlinear state-space systems, often accompanied by numerous empirical parameters, which complicates practical applications. To address this issue, the Goman–Khrabrov (G-K) dynamic stall model simplifies the state space and retains only two empirical parameters related to time delays. Our study finds that different developmental stages of dynamic stall exhibit various time delay scales. The G-K dynamic stall model, which utilizes a first-order time-invariant inertia system, forcibly unifies the time scales across different stages. Consequently, this leads to intractable nonphysical modeling errors. This paper introduces the latest revised G-K model that employs a time-varying state space system. This model not only maintains a concise form but also eliminates the nonphysical modeling errors previously mentioned. In response to the challenge of identifying empirical parameters, this paper presents a parameter identification method for both the original and revised G-K models utilizing a Physics-Informed Neural Network. The revised model was validated through dynamic stall load prediction cases for mild, moderate and deep dynamic stall on various airfoils, achieving a maximum accuracy improvement of up to 74.5%. The revised G-K model is capable of addressing a broader range and more complex practical applications.
Mechanisms of mass transfer effect for the vapor-gas bubble under acoustic excitation
Authors: Shen Junwei , Li Hao , Zheng Xiaoxiao , Zhang Yuning , Zhang Yuning
Published: January 2025

This paper theoretically explores the mechanisms of the mass transfer effect for the vapor-gas bubble under acoustic excitation. The mathematical model for the mixture bubble mass transfer is established based on the perturbation method. The threshold of the mixture bubble under different vapor mass fractions is compared with those of the gas bubble. The threshold represents the amplitude condition at which the molar quantity of gas within the bubble achieves the dynamic equilibrium state, which dictates whether the bubble expands or contracts. The main conclusions are summarized as follows: (1) The vapor mass fraction inside the mixture bubble has a significant effect on the mass transfer processes, including bubble growth, gas diffusion, and convection. (2) As the initial valor mass fraction increases, the resonance region moves in the direction of a decreasing equilibrium radius. In the region far above resonance, threshold curves of the mixture bubble show either an upward trend or a downward trend. (3) The bubble radius, vapor mass fraction, and threshold value all undergo variations during the mixture bubble's growth or shrinkage processes.
Impact of the motion effect of the cutoff facility on the dynamic energy loss of the prototype axial flow pump system during the startup process
Authors: Zhang Xiaowen , Pavesi Giorgio , Hu Chongyang , Song Xijie , Tang Fangping
Published: January 2025

Large pumping systems have emerged as one of the primary areas of energy consumption. During the startup process (SUP) of the axial flow pump system (AFPS), a complex interaction unfolds involving the motion of the cutoff facilities (COF), the acceleration of the pump, and the phenomenon of energy dissipation. The kinematic characteristics of the COF significantly influence the flow patterns, dynamic loads, and energy transfer experienced by the system. This study investigates the energy dissipation mechanism of a prototype AFPS (PAFPS) during SUP, utilizing a combination of experiments on engine starting characteristics, computational fluid dynamics, and in-field measurements of the PAFPS. Two COF motion modes are compared, revealing that accelerated gate opening improves transition efficiency and reduces energy consumption. Key findings highlight that accelerated gate motion minimizes turbulence-induced losses near the COF exit and suppresses high entropy production regions in the impeller domain, leading to smoother and more energy-efficient operations. These insights offer actionable strategies to enhance pump system performance during SUP.
Fresh groundwater lens evolution in artificial islands accompanied with silt uplift
Authors: Gao Chenchen , Zheng Tianyuan , Chang Qinpeng , Zhang Jian , Hao Yujie , Cao Min , Zheng Xilai , Luo Jian
Published: January 2025

Silt uplifts at the base of artificial islands have significant impacts on the development of fresh groundwater lenses and the desalination process within island aquifers, which were often overlooked in previous research. Using numerical simulations, we analyzed the effects of various silt uplift configurations on the evolution characteristics of freshwater lenses in artificial island aquifers. The results indicate that freshwater lenses in central uplift configurations reach steady state faster than those in marginal uplift configurations. In both central and marginal uplift configurations, increasing the silt uplift height substantially enhances the proportion of freshwater volume before reaching steady state. Longer silt uplifts initially increase the proportion of freshwater volume but ultimately reduce it at steady state due to spatial constraints. The silt uplift heights have minimal impact on the total salt mass removal rate in the central uplift configuration, whereas marginal uplifts with taller heights exhibit faster and higher salt removal rates until steady state. Short and tall silt uplifts expedite steady-state attainment in the central uplift configuration. For marginal silt uplifts, an increase in uplift height enhances the proportion of freshwater lens volume when the uplift length is less than 476 m. However, this proportion decreases when the uplift length exceeds 476 m. The influence of marginal uplift heights on the stabilization time is minor. Based on these findings, we could optimize the combination of short and tall silt uplifts to maximize freshwater volume and minimize the steady-state time, providing valuable insights for improving groundwater storage on artificial islands.
Effects of nozzle size and surface hydrophobicity on microbubble generation
Authors: Heidarian Alireza , Sun Bihai , Soria Julio
Published: January 2025

Microbubble dynamics in distilled water were experimentally investigated during three stages: formation, expansion, and detachment, emphasizing the combined effects of nozzle size and surface hydrophobicity. To achieve superhydrophobicity, nozzles with radii of 5, 15, 25, and 50 μm were fabricated using laser precision machining technology and treated with trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane. High-speed, high-spatial-resolution imaging was used to precisely measure the contact angle, instantaneous volume, radii of curvatures and detachment time of the microbubbles. The experimentally measured data were used to calculate the forces acting on bubbles, including the Young–Laplace pressure, surface tension, buoyancy, momentum, and added mass force. The results show that superhydrophobic nozzles generate larger, more elongated bubbles with extended detachment time, whereas non-hydrophobic nozzles form smaller, spherical bubbles that detach faster. Furthermore, it was observed that increasing the nozzle size decreases the size of bubbles generated by superhydrophobic nozzles, while it increases the bubble size for non-hydrophobic nozzles. A force balance analysis confirmed that in the expansion stage, the pressure force on bubbles from non-hydrophobic nozzles drops, while the surface tension and momentum force remain constant, leading to faster bubble growth and detachment. In contrast, for bubbles from superhydrophobic nozzles, the pressure force decreases gradually, while the surface tension changes continuously, resulting in a prolonged attachment and the formation of larger bubbles.
Origins of the rare Australian daisy Erigeron conyzoides and its implications for biological control research and conservation management
Authors: Chen Stephanie H. , Grealy Alicia , Rafter Michelle A. , Gooden Ben , Schmidt-Lebuhn Alexander N.
Published: January 2025

Context Confidence in risk analyses for weed biological control (biocontrol) agents is underpinned by knowledge of the phylogenetic associations between the target weed and off-target plant species, with an emphasis on native taxa that co-occur with the weed in its introduced range. The origins of off-target plant species are also considered when assessing potential adverse effects of releasing weed biocontrol agents into the environment. Erigeron bonariensis L. (flaxleaf fleabane), native to South America, is a major cropping weed in North America, Europe, and Australia. Phylogenomic analysis of the weed’s tribe, Astereae, for a biocontrol program has put into question the existence of native Australian fleabanes. Aims We aimed to resolve the establishment means of a supposed native species to Australia by testing its phylogenetic and morphological associations with other Erigeron taxa at a global scale. Methods Target-sequence capture data were combined with traditional taxonomy. Key results We rediscovered the closest presumed native relative of flaxleaf fleabane, the rare and declining E. conyzoides F.Muell. (daisy fleabane), during field work in Victoria, Australia. Molecular data and morphology indicated that E. conyzoides and E. acer L. from the northern hemisphere are not distinct. Conclusions Erigeron conyzoides is very likely not a distinct species endemic to Australia but rather a disjunct population of E. acer. Implications This finding improves confidence in the host-specificity of candidate biocontrol agents for fleabane in Australia, because we argue that the closest related truly native species is much more distantly related to fleabane than previously thought.
Molecular phylogeny and systematic revision of the Brazilian species of Mastigoproctus Pocock, 1894 (Arachnida: Uropygi: Mastigoproctinae)
Authors: Castro-Pereira Daniel , Pinto-da-Rocha Ricardo
Published: January 2025

Uropygi is an order of arachnids commonly known as vinegaroons or whip-scorpions. So far, two genera are known to occur in Brazil: Thelyphonellus Pocock, 1894 and Mastigoproctus Pocock, 1894. We examined the morphology of 182 specimens of Brazilian Mastigoproctus and sequenced 42 specimens for phylogenetic analyses, using mitochondrial and nuclear molecular markers. Phylogenetic inference was performed under maximum parsimony, maximum likelihood and Bayesian inference. Our results suggest that the Brazilian species previously included in Mastigoproctus represent two different genera, with the following species and synonymies: the revalidated Amauromastigon Mello-Leitão, 1931, composed of A. maximus (Tarnani, 1889), comb. nov. (=Mastigoproctus annectens Werner, 1916, M. butleri Pocock, 1894 and M. perditus Mello-Leitão, 1931), and Heptatarsus gen. nov., composed of H. brasilianus (Koch, 1843), comb. nov. (=Mastigoprotus minensis Mello-Leitão, 1931) and H. custodioi sp. nov. Also, we urge caution when using certain morphological characters when describing uropygid taxa based on specimens in early developmental stages. ZooBank: urn:lsid:zoobank.org:pub:9EF06715-2BA1-4616-A801-2239DBE3DAB4
Gravity from Pre-geometry
Authors: Addazi A , Capozziello S , Marcianò A , Meluccio G
Published: January 2025

The gravitational interaction, as described by the Einstein–Cartan theory, is shown to emerge as the by-product of the spontaneous symmetry breaking of a gauge symmetry in a pre-geometric four-dimensional spacetime. Starting from a formulation

a
`

la Yang–Mills on an

SO
(
1
,
4
)

or

SO
(
3
,
2
)

principal bundle and not accounting for a spacetime metric, the Einstein–Hilbert action is recovered after the identification of the effective spacetime metric and spin connection for the residual

SO
(
1
,
3
)

gauge symmetry of the spontaneously broken phase—i.e. the stabiliser of the

SO
(
1
,
4
)

or

SO
(
3
,
2
)

gauge group. Thus, the two fundamental tenets of general relativity, i.e. diffeomorphism invariance and the equivalence principle, can arise from a more fundamental gauge principle. The two mass parameters that characterise Einstein gravity, namely the Planck mass and the cosmological constant, are likewise shown to be emergent. The phase transition from the unbroken to the spontaneously broken phase is expected to happen close to the Planck temperature. This is conjectured to be dynamically driven by a scalar field that implements a Higgs mechanism, hence providing mass to new particles, with consequences for cosmology and high-energy physics. The couplings of gravity to matter are discussed after drawing up a dictionary that interconnects pre-geometric and effective geometric quantities. In the unbroken phase where the fundamental gauge symmetry is restored, the theory is potentially power-counting renormalisable without matter, offering a novel path towards a UV completion of Einstein gravity.
A method for stress and hardness characterization based on the amplitude spectrum features of magnetic Barkhausen noise
Authors: Fu Ping , Wang Yujue , He Cunfu , Li Peng , Ning Mengshuai , Xu Zhongqi , Liu Xiucheng
Published: January 2025

Hardness and residual stress on the surface serve as critical evaluation indicators for the quality of components in industrial manufacturing. However, determining their values becomes a substantial challenge when both these mechanical properties are variables. This study proposes a method for decoupling stress and hardness from the time–frequency domain of magnetic Barkhausen noise (MBN), aiming to distinguish between the two variable mechanical properties. Short-time Fourier transform is employed to obtain the amplitude spectrum of MBN, and features in both time and frequency domains are extracted. The relationship between the features of MBN and mechanical properties is examined. Our findings indicate that as hardness increases, the rate of change of MBN features with stress decreases. In contrast, at higher stress levels, the rate of change of MBN features with hardness increases. However, the frequency corresponding to the maximum value of the amplitude spectrum f
max remains constant despite changes in stress but exhibits an increase with increasing hardness. A model based on planar polynomial functions related to hardness and stress is developed to achieve decoupling. The method would serve as a valuable reference for the decoupling of two or more mechanical properties.
Toward large-scale PSD-based visible light positioning with visual–inertial fusion
Authors: Sun Fengming , Liu Zuoyuan , Zhong Ruiyang , Zhu Zhenyu , Liu Hongguang , Zhao Xinyi
Published: January 2025

Accurate large-scale indoor positioning is essential for location-based services. Visible light communication (VLC) holds promise for supporting global indoor positioning due to its inherent advantages, including immunity to electromagnetic interference and low development cost. As a type of optical receiver, the position-sensitive detector (PSD)-based visible light positioning (VLP) system provides accurate, high-update-rate absolute positioning results. However, its positioning range is constrained to 1 m2 due to light-emitting diode (LED) distribution and the receiver’s field of view, which is a common limitation of VLC-based positioning systems. To address this issue, a loosely coupled system is proposed in this paper through pose-graph optimization, which effectively integrated a PSD-based VLP system with visual–inertial odometry (VIO) capable of providing large-scale relative positioning. Unlike traditional VLP approaches that require dense LED deployment, our method enables large-scale indoor positioning through the sparse placement of multiple PSD-based positioning areas. Experiments were conducted in a real indoor environment to validate the effectiveness of the fusion system in large-scale areas and its capability to correct VIO-induced drift. Our proposed method provides precise position estimation in a local area of 1 m2, with a mean positioning error of 9.16 mm. In two large-scale indoor environments: a single room with a corridor and multiple rooms connected by a corridor, with a 1 m2 area of sufficient LED signal coverage and other regions experiencing LED shortage/outage area, the system provides both locally precise positioning and global drift correction.
A tunable quasi-zero-stiffness vibration isolator (QZS-VI) with magnetorheological elastomer (MRE)
Authors: Dingxin Leng , Xu Zhou , Wenhao Feng , Donghong Ning , Guijie Liu
Published: January 2025

This paper presents a field-tunable quasi-zero stiffness vibration isolator (QZS-VI), which is beneficial for broadening the frequency bandwidth for low-frequency mitigation. The proposed QZS-VI was constructed by embedding a magnetorheological elastomer (MRE) device into an X-shaped QZS-VI system, which fulfills the tuning capability of vibration isolation. The MRE-based X-shaped system provides tunable negative stiffness, and a vertical spring supports the isolated loadings. The restoring force and stiffness of MRE-based QZS-VI is theoretically investigated, by which the field-induced QZS range (especially a large QZS range in high current values) is analyzed. A dynamic model of MRE-based QZS-VI is established and its isolation performance is numerically studied. The results show that, by controlling the current in the MRE device coil, the system transmissibility can be greatly reduced when the isolation system is under multi-frequency excitation. Furthermore, a prototype of MRE-based QZS-VI is developed, and the verification experiment is conducted. The proposed MRE-based QZS-VI system may be considered as a controllable vibration isolation candidate for random low-frequency excitation.
How exchange symmetry impacts performance of collective quantum heat engines
Authors: Boeyens Julia , Yadin Benjamin , Nimmrichter Stefan
Published: January 2025

Recently, multilevel collectively coupled quantum machines like heat engines and refrigerators have been shown to admit performance enhancements in analogy to superradiance. Thus far, investigations of the performance of collective quantum machines have largely restricted the dynamics to particles with bosonic exchange symmetry, especially for large numbers of particles. However, collections of indistinguishable but not fundamentally identical particles may assume quantum states of more general exchange symmetry or combinations thereof, raising the question of whether collective advantages can be observed for dynamics that allow the full Hilbert space to be explored. Here, we compare a collection of single-particle three-level masers with their collectively coupled counterpart, while admitting more general forms of exchange symmetry. We study ergotropy and emitted power as the figures of merit and show which of the known results applicable to a single three-level engine carry over to an engine made up of a collectively coupled ensemble. We do this using results from representation theory to characterise the full basis of the Hilbert space and provide general tools for the description of the dynamics of such systems. We find that collective work extraction can extend beyond the temperature window of three-level lasing, whereas in the lasing regime, individual may outperform collective operation. In addition, the optimal parameter regime for work-like energy output varies for different symmetry types. Our results show a rich picture in which bosonic symmetry is not always optimal and sometimes individual particles may even perform best.
Cosmological constraints from weak lensing scattering transform using HSC Y1 data
Authors: Cheng 程 Sihao 思浩 , Marques Gabriela A. , Grandón Daniela , Thiele Leander , Shirasaki Masato , Ménard Brice , Liu Jia
Published: January 2025

As weak lensing surveys go deeper, there is an increasing need for reliable characterization of non-Gaussian structures at small angular scales. Here we present the first cosmological constraints with weak lensing scattering transform, a statistical estimator that combines efficiency, robustness, and interpretability. With the Hyper Suprime-Cam survey (HSC) year 1 data, we obtain Ωm = 0.29-0.03
+0.04, SS8 ≡ σ
8(Ωm/0.3)0.5 = 0.83±0.02, and intrinsic alignment strength A
IA = 1.0±0.4 through simulation-based forward modeling. Our constraints are consistent with those derived from Planck. The error bar of Ωm is 2 times tighter than that obtained from the power spectrum when the same scale range is used. This constraining power is on par with that of convolutional neural networks, suggesting that further investment in spatial information extraction may not yield substantial benefits.

We also point out an internal tension of S
8 estimates linked to a redshift bin around z ∼ 1 in the HSC data. We found that discarding that bin leads to a consistent decrease of S
8 from 0.83 to 0.79, for all statistical estimators. We argue that photometric redshift estimation is now the main limitation in the estimation of S
8 using HSC. This limitation is likely to affect other ground-based weak lensing surveys reaching redshifts greater than one. Alternative redshift estimation techniques, like clustering redshifts, may help alleviate this limitation.
Sensitivity of WIMP bounds on the velocity distribution in the limit of a massless mediator
Authors: Choi Koun , Jeong Injun , Kang Sunghyun , Kar Arpan , Scopel Stefano
Published: January 2025

We discuss the sensitivity of the bounds on the spin-independent (SI) and spin-dependent (SD) WIMP-proton and WIMP-neutron interaction couplings α
SI,SD

p,n
on the WIMP
velocity distribution for a massless mediator. We update the bounds in the Standard Halo Model (SHM) for direct detection and the neutrino signal from WIMP annihilation in the Sun (fixing the
annihilation channel to bb̅), and set a halo-independent bound for the first time using
the single-stream method. In the case of a massless mediator the SHM capture rate in the Sun
diverges and is regularized by removing the contribution of WIMPs locked into orbits that extend
beyond the Sun-Jupiter distance. We discuss the dependence of the SHM bounds on the Jupiter cut
showing that it can be sizeable for α
SD
p and a WIMP mass mχ
exceeding 1
TeV. Our updated SHM bounds show an improvement between about two and three orders of magnitude
compared to the previous ones in the literature. Our halo-independent analysis shows that, with
the exception of α
SD
p at large mχ
, the relaxation of the bounds compared to
the SHM is of the same order of that for contact interactions, i.e. relatively moderate in the low
and high WIMP mass regimes and as large as ∼ 102 for mχ
≃ 20 GeV. On the other
hand, the exact determination of the relaxation of the bound becomes not reliable for α
SD
p and mχ
≳ 1 TeV due to the sensitivity of the SHM capture rate in the Sun to
the details of the Maxwellian velocity distribution at low incoming WIMP speeds. In contrast, the
halo-independent bounds are robust against the details of the velocity distribution including the
Jupiter cut and the local escape speed, as expected.
Investigating binary-neutron-star mergers as production sites of high-energy neutrinos
Authors: Rossoni S. , Boncioli D. , Sigl G.
Published: January 2025

The end state of binary-neutron-star (BNS) mergers can manifest conditions to produce high-energy neutrinos. Inspired by the event GW170817, detected in gravitational waves and in optical/infrared emission, we investigate a scenario in which cosmic-ray (CR) particles are accelerated, in a population of BNS mergers, in the energy range that might contribute from the knee to the ankle of the CR measured spectrum. By taking into account the measured thermal and non-thermal energy density of the photon fields in the source environment as a function of the time after the merger, we model the CR interactions and the consequent neutrino production. We propagate the escaped CR and neutrino fluxes through the extragalactic space and compare the expected diffuse fluxes to the experimental data and current limits. Depending on the CR spectral and composition parameters at acceleration, and on the possible contribution to the sub-ankle CR flux, we discuss the predicted diffuse neutrino flux associated to this class of astrophysical objects, as a function of the details of the photon field characterizing the merger stage, including its evolution in time. We constrain the fraction of accelerated baryons in the source site given the BNS merger rate per volume, taking into account at the same time the constraints from the measured CR and neutrino fluxes.
Semi-empirical approach to [CII] line intensity mapping
Authors: Roy Anirban , Lapi Andrea
Published: January 2025

The line intensity mapping technique involves measuring the cumulative emission from specific spectral lines emitted by galaxies and intergalactic gas. This method provides a way to study the matter distribution and the evolution of large-scale structures throughout the history of the Universe. However, modeling intensity mapping from ab-initio approaches can be challenging due to significant astrophysical uncertainties and noticeable degeneracies among astrophysical and cosmological parameters. To address these challenges, we develop a semi-empirical, data-driven framework for galaxy evolution, which features a minimal set of assumptions and parameters gauged on observations. By integrating this with stellar evolution and radiative transfer prescriptions for line emissions, we derive the cosmic [CII] intensity over an extended redshift range 0 ≲ z ≲ 10. Our approach is quite general and can be easily applied to other key lines used in intensity mapping studies, such as [OIII] and the CO ladder. We then evaluate the detectability of the [CII] power spectra using current and forthcoming observational facilities. Our findings offer critical insights into the feasibility and potential contributions of intensity mapping for probing the large-scale structure of the Universe and understanding galaxy evolution.
Anisotropies of cosmological gravitational wave backgrounds in non-flat spacetime
Authors: Cai Rong-Gen , Wang Shao-Jiang , Yuwen Zi-Yan , Zeng Xiang-Xi
Published: January 2025

Recent reports of stochastic gravitational wave background from four independent pulsar-timing-array collaborations have renewed the interest in the cosmological gravitational wave background (CGWB), which is expected to open a new window into the early Universe. Although the early Universe is supposed to be extremely flat from an inflationary point of view, the cosmic microwave background (CMB) data alone from the Planck satellite measurement prefers an enhanced lensing amplitude that can be explained by a closed Universe. In this paper, we propose an independent method to constrain the early-Universe flatness from the anisotropies of CGWB. Using the generalized harmonic decompositions in the non-flat spacetime, we find CGWBs from different physical mechanisms such as cosmic inflation and phase transitions share the same integrated Sachs-Wolfe (ISW) term but possess different SW terms, which would exhibit different behaviors when including the spatial curvature since the ISW effect is more sensitive to the spatial curvature than the SW effect. Furthermore, we provide the cross-correlations between CGWB and CMB, implying a positive or negative correlation between their SW effect terms depending on the GW mechanisms, which may hint at the sign of f
NL when considering non-Gaussianity contributions to anisotropies.
Thermodynamic and observational constraints on black holes with primary hair in Beyond Horndeski gravity: Stability and shadows
Authors: Erices Cristian , Fathi Mohsen
Published: January 2025

In this paper, we find that unlike in General Relativity, the shift-symmetric subclass of
Beyond Horndeski theories permits black holes with primary hair that are thermodynamically stable
and align with current Event Horizon Telescope observations of the M87* and Sgr A* black
holes. This work begins by investigating thermodynamic properties, analyzing how primary hair
influences thermodynamic quantities and local stability, which imposes strict constraints on the
allowed range of primary hair values. The null geodesics near this black hole are then examined,
demonstrating how scalar hair affects the shadow diameter. Specifically, when the parameter of the
Beyond Horndeski function F
4 is negative, increasing scalar hair enlarges the shadow; in
contrast, when this parameter is positive, greater scalar hair reduces the shadow size. Further
constraints on the scalar hair are derived using observational data, highlighting its sensitivity
to other black hole parameters. To explore additional observational features, face-on
two-dimensional images of spherically infalling accretion disks are simulated, revealing how
primary scalar hair shapes the black hole's shadow. Finally, all relevant constraints are combined
to identify black holes that are both stable and consistent with observational data.
Fast Radio Bursts and Artificial Neural Networks: a cosmological-model-independent estimation of the Hubble constant
Authors: Fortunato Jéferson A.S. , Bacon David J. , Hipólito-Ricaldi Wiliam S. , Wands David
Published: January 2025

Fast Radio Bursts (FRBs) have emerged as powerful cosmological probes in recent years
offering valuable insights into cosmic expansion. These predominantly extragalactic transients
encode information on the expansion of the Universe through their dispersion measure, reflecting
interactions with the intervening medium along the line of sight. In this study, we introduce a
novel method for reconstructing the late-time cosmic expansion rate and estimating the Hubble
constant, solely derived from FRBs measurements coupled with their redshift information while
employing Artificial Neural Networks. Our approach yields a Hubble constant estimate of H
0 =
68.2 ± 7.1 km s-1 Mpc-1. With a dataset comprising 21 localised data points, we
demonstrate a precision of ∼ 10%. However, our forecasts using simulated datasets indicate
that in the future it could be possible to achieve precision comparable to the SH0ES collaboration
or the Planck satellite. Our findings underscore the potential of FRBs as alternative, independent
tools for probing cosmic dynamics.
Mapping dark matter in the Milky Way using normalizing flows and Gaia DR3
Authors: Lim Sung Hak , Putney Eric , Buckley Matthew R. , Shih David
Published: January 2025

We present a novel, data-driven analysis of Galactic dynamics, using unsupervised machine learning — in the form of density estimation with normalizing flows — to learn the underlying phase space distribution of 6 million nearby stars from the Gaia DR3 catalog.
Solving the equilibrium collisionless Boltzmann equation, we calculate — for the first time ever — a model-free, unbinned estimate of the local acceleration and mass density fields within a 3 kpc sphere around the Sun.
As our approach makes no assumptions about symmetries, we can test for signs of disequilibrium in our results.
We find our results are consistent with equilibrium at the 10% level, limited by the current precision of the normalizing flows.
After subtracting the known contribution of stars and gas from the calculated mass density, we find clear evidence for dark matter throughout the analyzed volume.
Assuming spherical symmetry and averaging mass density measurements, we find a local dark matter density of 0.47± 0.05 GeV/cm3.
We compute the dark matter density at four radii in the stellar halo and fit to a generalized NFW profile. Although the uncertainties are large, we find a profile broadly consistent with recent analyses.
Atomic Origin of Minor Alloying Element Effect on Glass Forming Ability of Metallic Glass
Authors: Zhang Shan , Li Qingan , Yang Yong , Guan Pengfei
Published: January 2025

The glass-forming ability (GFA) of metallic glasses is a key scientific challenge in their development and application, with compositional dependence playing a crucial role. Experimental studies have demonstrated that the addition of specific minor elements can greatly enhance the GFA of parent alloys, yet the underlying mechanism remains unclear. In this study, we use the ZrCuAl system as a model to explore how the addition of minor Al influences the crystallization rate by modulating the properties of the crystal-liquid interface, thereby affecting the GFA. The results reveal that the minor addition of Al significantly reduces the crystal growth rate, a phenomenon not governed by particle density fluctuations at the interface. The impact of minor element additions extends beyond a modest increase in crystal-unfavorable motifs in the bulk supercooled liquid. More importantly, it leads to a significant enrichment of these motifs at the crystal-supercooled liquid interface, forming a dense topological network of crystal-unfavorable structures that effectively prevent the growth of the crystalline interface and enhance GFA. Our results provide valuable insights for the design and development of high-performance metallic glasses.
Structural and transport properties of (Mg,Fe)SiO3 at high temperature and high pressure
Authors: Huang Shu , Xiang Zhiyang , He Shi , Yin Luhan , Zhang Shihe , Chen Chen , He Kaihua , Lu Cheng
Published: January 2025

(Mg,Fe)SiO3 is primarily located in the mantle and has a substantial impact on geophysical and geochemical processes. Here, we employ molecular dynamics simulations to investigate the structural and transport properties of (Mg,Fe)SiO3 with varying iron contents at temperatures up to 5000 K and pressures up to 135 GPa. We thoroughly examine the effects of pressure, temperature, and iron content on the bond lengths, coordination numbers, viscosities, and electrical conductivities of (Mg,Fe)SiO3. Our calculations indicate that the increase of pressure leads to the shortening of the O-O and Mg-O bond lengths, while the Si-O bond lengths exhibit the initial increase with pressure up to 40 GPa, after which it is almost unchanged. The coordination numbers of Si transition from four-fold to six-fold and eventually reaching eight-fold coordination at 135 GPa. The enhanced pressure causes the decrease of the diffusion coefficients and the increases of viscosities of (Mg,Fe)SiO3. The increased temperatures slightly decrease coordination numbers and viscosities, as well as obviously increase diffusion coefficients and electrical conductivities of (Mg,Fe)SiO3. Additionally, iron doping facilitates the diffusion of Si and O, reduces viscosities, and enhances electrical conductivities of (Mg,Fe)SiO3. These findings advance fundamental understanding of the structural and transport properties of (Mg,Fe)SiO3 under high temperature and high pressure, which provide novel insights for unraveling the complexities of geological processes within the Earth's mantle.
The effect of dynamic shock load on the adhesion strength of fiber reinforced composite plates
Authors: Ganapathy Sakthi Balan , Aravind Raj S
Published: January 2025

In order to optimize the best possible combination, three input variants that influence adhesion properties were chosen for this investigation. The adhesives, fillers used to blend with the adhesives, and surface treatments were selected for this objective. This study has selected these input variants to compare the adhesion property between a thermoset composite and thermoplastic composite plate. The adhesion joint zone was subjected to dynamic impact shock loading, and the adhesion strength was analyzed both before and after the shock exposure. In order to determine the extents of the adhesion strength reduction subsequent to dynamic loading, the specimens’ were evaluated both prior to and subsequent to shock loading. Three distinct thermoset adhesives, including vinyl ester, epoxy, and polyester, are blended with ceramic particles, including silicon and hafnium carbide, are used to bond the composites. In a 1:50 ratio, the additives were incorporated into the adhesives. To assess shock pressure-induced damage, the specimens were characterized after experimentation. The shock exposure appears to have degraded the material extruded specimen’s surface, leaving the interface unmodified. The responses were found to be contingent upon the type of filler used during adhesive blending and the surface treatment. After 50 shocks, composite plates’ adhesion property decreased slightly but after 100 shocks, it decreased significantly. The study found that the composite plate adhesion dropped by 4.97% after 50 shocks. After 100 shocks, adhesion strength dropped 25.46%.