bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gravity from Pre-geometry
Authors: Addazi A , Capozziello S , Marcianò A , Meluccio G 
Published: January 2025

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
(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.