General Relativity and Quantum Cosmology
From gravastar to central singularity
G.E. Volovik
We consider the model of the regular black hole, which demonstrates that the gravastar is thermodynamically unstable towards the Schwarzschild black hole with singularity.
High Energy Astrophysical Phenomena
Semi-Analytical Model for the Evolution of Stellar Binaries in the Empty Loss Cone of Massive Black Holes
Samuel McGuire, Evgeni Grishin, Ilya Mandel et al. (+1 more)
Binary
star systems orbiting close to a supermassive black hole (SMBH) evolve through encounters with other
stars, the SMBH's
tidal forces, and the binary's internal dynamics, including general relativistic precession and tides. Many are driven onto highly eccentric inner binary orbits, potentially leading to
stellar mergers; other possible outcomes include hypervelocity
star ejections or
tidal disruption events. We study the
evolution of binaries in the empty loss cone regime, where the outer orbit's angular momentum change per orbit due to scattering off other
stars is smaller than the outer angular momentum at the
tidal separation radius. We build on the work of Hamers & Samsing to develop a computationally efficient semi-analytical model that captures the long term
evolution of binaries in perturbative regimes where the ratio of the binary
tidal separation radius to the pericenter around the SMBH is smaller than 0.15. Crucially, we apply corrections to preserve the orthogonality between the binary's eccentricity and angular momentum vectors, which prevents unphysical eccentricity growth. From these simulations, we find analytical fits for the probability distributions of the final orbital parameters of binaries approaching the SMBH. We find that general relativistic precession efficiently suppresses von-Zeipel-Lidov-Kozai-like eccentricity oscillations and reduces the fraction of merging binaries from $84\%$ with Newtonian physics only, to $3\%$ with precession included.
Stellar tides further reduce the merger fraction to $0.4\%$.
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All authors Samuel McGuire, Evgeni Grishin, Ilya Mandel, Yuri Levin
Superconductivity
Self-consistent GW theory for superconductivity in SrTiO3 models
Zhi-Hao Cui, John Sous, Andrew J. Millis et al. (+1 more)
Superconductivity in doped SrTiO$_3$ occurs over a wide range of carrier densities, including those for which the
Fermi energy is below the polar longitudinal optical
phonon scale. In this regime, the assumptions underpinning conventional implementations of Migdal-Eliashberg theory, including frequency cutoffs at the
phonon scale and a Coulomb pseudopotential $\mu^\ast$, are not valid. We solve the finite-temperature $GW$ equations with full momentum and frequency dependence, without cutoffs or $\mu^\ast$, for polar one-band models of SrTiO$_3$, using effective masses and three-
phonon dielectric functions parameterized from ab initio calculations. Comparing different self-consistency levels, namely $G_0W_0$, $GW_0$, and fully self-consistent $GW$, we find that the one-shot ($G_0W_0$) kernel overestimates the pairing-onset temperature by one to two orders of magnitude. The dominant suppression comes from replacing $G_0$ by $G$, thereby incorporating the
phonon renormalization factor in the electron Green function. Using the self-consistently computed interaction $W$ further lowers and narrows the pairing-onset dome. In the dilute limit, our calculations identify the pairing channel as the Fröhlich
phonon interaction screened by the incipient ferroelectricity of the material, with plasmonic and electronic screening effects negligible. The numerical solution of the full equations reveals a pairing-onset scale that remains non-zero as the density tends to zero, whereas
Fermi-surface projection or
Fermi-energy frequency truncation removes it. This work highlights the relevance of incipient ferroelectricity, the importance of self-consistency, and the need for a full momentum- and frequency-dependent treatment in modeling superconductivity in SrTiO$_3$-like doped polar
semiconductors.
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All authors Zhi-Hao Cui, John Sous, Andrew J. Millis, David R. Reichman
Nuclear Theory
Nonlinear collective flow reveals the breakdown of quadrupole–hexadecapole scaling in heavy ion collisions
Hadi Mehrabpour, Zahra Sheibani, Li Yan et al. (+2 more)
Determining the role of intrinsic hexadecapole deformation ($\beta_4$) in
nuclear structure remains a long-standing challenge. Relativistic heavy-ion collisions provide a unique opportunity to address this problem by converting the initial
nuclear geometry into the collective motion of the
quark–
gluon plasma (QGP). Using event-by-event viscous hydrodynamic simulations of ultra-central $^{238}$U+$^{238}$U collisions at $\sqrt{s_{NN}}=193$ GeV, we investigate whether higher-order collective flow can isolate the contribution of $\beta_4$ and test the $\beta_2-\beta_4$ correlation. We demonstrate that information carried by the sign of $\beta_4$ survives the QGP
evolution and is enhanced through nonlinear hydrodynamic response: the fourth-order flow harmonic acquires its
topology dependence predominantly from the linear response, whereas the sensitivity of the sixth-order harmonic originates almost entirely from nonlinear mode coupling. As a consequence, the nonlinear response coefficient $\xi_{6,222}$ cleanly separates the $(\beta_2,\beta_4)$ intrinsic
nuclear topologies. These results establish the sign of $\beta_4$ as an experimentally accessible signature of deviations from the quadrupole–hexadecapole correlation, demonstrating that higher-order collective flow provides a direct probe of
nuclear multipole structure while revealing how nonlinear QGP dynamics encode subtle higher-order
geometric information into final-state observables.
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All authors Hadi Mehrabpour, Zahra Sheibani, Li Yan, Chunjian Zhang, Abolfazl Mirjalili
General Relativity and Quantum Cosmology
Novel extended inner shadow in images of Johannsen-Psaltis black holes with thin accretion disks
Xinyu Wang, Xiaobao Wang, Xin-Yang Wang et al. (+1 more)
The Johannsen-Psaltis (JP) metric is constructed by introducing deviation parameters into the Kerr metric. The presence of these deviation parameters provides additional degrees of freedom for testing the extent to which astrophysical black holes are consistent with the Kerr paradigm and for examining the validity of the no-hair
theorem. Since black hole imaging provides one of the most direct means of probing the properties of astrophysical black holes, a detailed investigation of the imaging characteristics of JP black holes constitutes a natural first step toward employing the JP metric to explore potential deviations from the Kerr geometry in astrophysical black hole systems. Accordingly, numerical backward ray-tracing simulations are employed to conduct a comprehensive investigation of the image structures, intensity distributions, and
redshift-blueshift signatures of JP black holes with both closed and non-closed event horizons. The dependence of these imaging characteristics on the deviation parameter is also investigated systematically. Furthermore, the emergence of an extended inner shadow, distinct from the original inner shadow of the black hole, in images of JP black holes with non-closed event horizons motivated a detailed investigation of its physical formation mechanism using both numerical backward ray-tracing simulations and an approximate analytical framework.
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All authors Xinyu Wang, Xiaobao Wang, Xin-Yang Wang, Minyong Guo
Materials Science
Alchemical thermodynamic integration for ab initio free-energy calculations in solutions
Liangrui Wei, Feng Zhang, Renata M. Wentzcovitch et al. (+2 more)
We develop an alchemical thermodynamic integration scheme that couples ab initio force calculators on the fly during Monte Carlo and molecular dynamics simulations. The implementation is validated against existing hybrid-
Hamiltonian approaches. The scheme yields ab initio free energies of high-pressure Fe-Ni and ambient Li-Na
liquid solutions that agree with previous calculations and reproduce the experimentally observed Li-Na miscibility gap. The code has an efficiency comparable to standard ab initio molecular dynamics. These results establish this scheme as a practical alchemical-integration framework for first-principles free-energy calculations in solutions.
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All authors Liangrui Wei, Feng Zhang, Renata M. Wentzcovitch, Kai-Ming Ho, Yang Sun
High Energy Astrophysical Phenomena
The XMM-Newton Line Emission Analysis Program (X-LEAP) III: Earth's Magnetospheric X-ray Emission Revealed by 22-Year XMM-Newton Observations
Zeyang Pan, Zhijie Qu, Yuqi Gong et al. (+5 more)
The magnetosphere, protecting the Earth from intense
solar activity, is also shaped by the
solar wind, while its structure is still uncertain in observation. In this study, we map the X-ray emission in the magnetosphere, which is induced by the charge exchange between the highly-ionized
solar wind and the neutral gas around the Earth, known as the magnetospheric
solar wind charge exchange (SWCX). In particular, we extract the magnetospheric SWCX in the O VII line emission data adopted from the XMM Line Emission Analysis Program (X-LEAP). The observed magnetospheric SWCX shows an enhanced emission of approximately $I_{\rm OVII}^{\rm mag}\approx 2$
photons $\rm cm^{-2}~ s^{-1}~sr^{-1}$ toward the Sun, showing a consistent shape predicted by numerical simulations. Furthermore, this magnetospheric SWCX exhibits a dependence on the XMM pointing direction, which traces the path length of SWCX emission in the Earth's magnetosphere. Building on this directional dependence, we model the 3D magnetosheath structure using soft X-ray observations for the first time, constraining the averaged boundary geometry and SWCX emissivity distribution over 22 years. Finally, utilizing the XMM data, we derive an empirical O VII emission efficiency of $\alpha_{\rm OVII}=(2.1\pm0.4) \times 10^{-16}\ {\rm eV\,cm^{2}}$.
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All authors Zeyang Pan, Zhijie Qu, Yuqi Gong, Tianran Sun, Joel N. Bregman, Yingjie Zhang, Li Ji, Jifeng Liu
Quantum Physics
Quantum sensing of low-frequency electric signal enabled by modulated auxiliary field in Rydberg atoms
Xiayang Fan, Shenchao Jin, Jiatian Liu et al. (+3 more)
Rydberg atoms have emerged as a versatile and efficient platform for high-sensitivity
quantum sensing of free-space electric fields, with remarkable progress in detecting low-frequency signals. To date, low-frequency Rydberg receivers have relied on a constant bias field, typically realized via intra-
cell electrodes or Rydberg
plasmas generated by photoelectric effects or inter-atomic interactions. While these approaches improve sensitivity, they suffer from inherent challenges in calibration, long-term stability, and robustness, hindering practical deployment. Here, we propose, design, and experimentally demonstrate a
quantum sensing scheme for low-frequency electric signals using modulated auxiliary fields in Rydberg atoms. Unlike conventional methods that employ external DC electric fields that are often fully shielded by adsorbed atom layers on the
cell walls, we introduce an AC-field modulation strategy. The incoming low-frequency signal mixes with the auxiliary field, and together they induce Stark shifts of the Rydberg level. These shifts are mapped onto the probe
laser via electromagnetically induced transparency (EIT), in a manner analogous to heterodyne detection. We demonstrate a sensitivity of $7.5 \pm 2.6~\mathrm{\mu V/(cm\cdot Hz^{1/2})}$ at 5 kHz and a minimal detectable field of $0.26 \pm 0.04~\mathrm{\mu V/cm}$ with an integration time of 1000 s. Furthermore, we extend this approach to systematically analyze the performance of generalized auxiliary fields containing multiple frequency components. By virtue of modulated auxiliary field and
quantum frequency mixing, our results establish a robust and systematic framework for
quantum sensing of low-frequency electric fields with Rydberg atoms, offering improved sensitivity, stability, and immunity to environmental drifts.
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All authors Xiayang Fan, Shenchao Jin, Jiatian Liu, Jialiang Zhang, Qichao Qi, Yuan Sun
Computational Physics
Uncertainty quantification in mechanics: A unified Bayesian perspective
Sascha Ranftl, Malte Rolf, Gerhard A. Holzapfel et al. (+1 more)
Uncertainty quantification (UQ) is essential to experimental mechanics, but has become particularly relevant in computational mechanics, manifesting in two fundamental problem types: forward and inverse problems. The former addresses how input uncertainties propagate to the quantities of interest, whereas the latter aims to infer unknown parameters from experimental observations or simulations. Since efficient propagation typically requires a prohibitive number of evaluations to compute marginal output distributions, the development of fast, data-driven surrogate models becomes necessary. Thus, we can distinguish between two inverse tasks: (i) the identification and calibration of input uncertainties, and (ii) the construction of surrogates, a methodology collectively referred to as surrogate-based UQ. Building on probabilistic
reasoning and the concept of partial belief, we demonstrate that
Bayesian probability theory provides a unified theoretical framework for addressing both problem types. We further show that
Bayesian inference allows for the seamless incorporation of essential subproblems, including model selection for identifying the most probable model specifications and experimental design for optimizing data collection by identifying experiments or simulations that maximize expected information gain about parameters, among others such as connections to sensitivity analysis or the use of special priors like random fields. While this theoretical framework is presented for general mechanical problems, particular emphasis is placed on biomechanics, where variability and uncertainty is especially pronounced due to inherent biological heterogeneity, patient-specific variability, and noisy data.
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All authors Sascha Ranftl, Malte Rolf, Gerhard A. Holzapfel, Ellen Kuhl
Mesoscale and Nanoscale Physics
Charge transfer mediated anomalous photoluminescence enhancement in monolayer MoS2 graphene heterostructure via polystyrene assisted wet transfer
Anagha Gopinath, Arpan De, Dipak Maity et al. (+1 more)
Van der Waals MoS2
graphene heterostructures are compelling candidates for high performance electronic and optoelectronic device applications. However, the interlayer charge transfer typically quenches the photoluminescence of monolayer MoS2, limiting the use of these
heterostructures in light emitting applications. In this work, we report an anomalous photoluminescence enhancement in n-type monolayer MoS2 by integrating it with monolayer
graphene via polystyrene assisted wet transfer process. Photoluminescence spectroscopy reveals a dominant trion to
exciton conversion in the
heterostructure. Kelvin probe force microscopy shows a 600 meV increase in the work function of MoS2 upon
heterostructure formation. This work function shift, together with the higher work function of
graphene, signifies electron transfer from MoS2 to
graphene. Shifts in the
graphene G and 2D Raman modes further corroborate the interlayer charge transfer. Hydroxyl and epoxy functionalization of
graphene following
heterostructure formation is evidenced by X ray photoelectron spectroscopy. DFT based Bader charge analysis quantifies the role of these functional groups in facilitating interlayer charge transfer. Collectively, our findings establish polystyrene assisted wet transfer as a practical interface engineering strategy for enhancing excitonic emission in MoS2
graphene heterostructures, thereby advancing their potential for scalable optoelectronic devices.
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All authors Anagha Gopinath, Arpan De, Dipak Maity, Jyoti Mohanty
Quantum Physics
Trade-off between predictability and quantum coherence for multi-path interferometry and its operational interpretation
Ezra Acalapati
The complementarity principle is a cornerstone of
quantum mechanics. In this work, we investigate a complementarity relation between the predictability and
quantum coherence, respectively, representing the particle-like and wave-like behaviour in wave–particle duality, in a multi-path setup. We introduce a basis-dependent predictability defined by the Bures distance between the state dephased in the chosen basis and the maximally mixed state. The predictability depends only on the observed basis statistics and admits a closed form in terms of the Bhattacharyya overlap. We derive a trade-off relation between the predictability and a coherence measure defined based on the nonclassicality of the Kirkwood–Dirac quasiprobability. For pure states, the trade-off relation is an exact equality. Remarkably, this wave–particle duality relation endows the coherence measure with an operational interpretation as the classically irreducible part of measurement randomness, yielding a tight worst-case bound on the guessing probability in source-independent QRNG.
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Optics
Raman-Assisted Multiband Nonlinear Frequency-Conversion Network in a High-Q LTOI Microdisk
Zhifan Fang, Yuxuan He, Zhangning Pan et al. (+2 more)
On-chip nonlinear frequency conversion offers a key route to broadband coherent light sources, but spanning telecom, visible, and ultraviolet wavelengths within a single resonator remains challenging. Lithium tantalate-on-
insulator (LTOI), which has recently emerged as a promising material platform for integrated photonics, combines strong Raman activity, a large second-order nonlinearity, broad optical transparency and high resistance to photorefractive damage, thereby attracting increasing
attention for on-chip nonlinear frequency conversion. Here, we experimentally demonstrate a Raman-assisted multiband frequency-conversion network in a high-Q LTOI microdisk with a loaded quality factor of 2.48x10^6. The resonant pumping produced high-purity single-mode Raman lasing with a 3.14 mW threshold, 32.44% slope efficiency, and an excellent side-mode suppression ratio (SMSR) of 29.5 dB. Under a nearby pump condition, we also observe multiple Stokes components together with an anti-Stokes line on the short-wavelength side of the pump. The resulting multiple intracavity Stokes fields subsequently acted as frequency seeds for cascaded chi^(2) processes, producing near-infrared and visible signals and extending the emission to 312.6 nm in the ultraviolet. These findings establish the cooperative action of Raman gain and second-order nonlinearity across widely separated spectral bands within a single microcavity. The device therefore offers a route toward integrated multiband light sources and a platform for studying coupled nonlinear dynamics.
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All authors Zhifan Fang, Yuxuan He, Zhangning Pan, Xianfeng Chen, Yuping Chen
High Energy Physics (Phenomenology)
LFV decays in a 3-3-1 model with singlet leptoquarks
N.H.T. Nha, L.T. Hue, N. T. K. Ngan et al. (+3 more)
Motivated by a recent study of the 3-3-1 model supplemented with a singlet scalar leptoquark, which successfully explains the
muon anomalous
magnetic moment and the decay $\mu\to e\gamma$ within current experimental constraints, we extend the phenomenological analysis of this framework to include the
lepton-
flavor-violating decays of the Standard Model-like
Higgs and the $Z$
boson. An interesting feature is that the branching ratios of these decays exhibit a nearly linear correlation with the corresponding charged
lepton flavor-violating radiative decays, namely $\mathrm{Br}(h,Z\to e_b^\pm e_a^\mp)\propto\mathrm{Br}(e_b\to e_a\gamma)$. Furthermore, the model exhibits a complementary interplay between the charged-
lepton anomalous
magnetic moments: parameter regions with $|\Delta a_{\mu}|\geq10^{-11}$ favor $\mathrm{Br}(h,Z\to\tau^\pm\mu^\mp)$ reaching their current experimental upper limits while keeping $|\Delta a_e|$ negligible, whereas regions with $10^{-14}\leq|\Delta a_e|\leq 8\times10^{-13}$ instead allow $\mathrm{Br}(h,Z\to\tau^\pm e^\mp)$ to approach the present experimental sensitivities but simultaneously suppress $|\Delta a_\mu|$ to the level of $\mathcal{O}(10^{-16})$.
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All authors N.H.T. Nha, L.T. Hue, N. T. K. Ngan, P.T. Bich, T.T. Hong, N.T. Tham
Astrophysics of Galaxies
Divyansh Srivastava, Andrzej Niedzielski and Rodolfo Smiljanic
Gaia DR3 provides astrophysical parameters for hundreds of millions of
stars, but the
metallicities [M/H] from its GSP-Phot module suffer from systematic biases. We estimate
stellar metallicities from
Gaia DR3 data using the homogeneous spectroscopic iron abundances [Fe/H] of LAMOST DR10 as training labels. We cross-matched LAMOST DR10 with
Gaia DR3 and trained a gradient-boosted decision-tree regressor (XGBoost) on 1.20 million AFGK
stars using only
Gaia-derived inputs and proxies. We validated the estimates on held-out LAMOST
stars, GALAH DR4, APOGEE DR17, and 46 open clusters, and applied the model to measure the radial
metallicity gradient of the Milky Way disk. On the held-out test set, the model achieves a mean absolute error of 0.052 dex and $R^2=0.94$ with negligible bias, compared with 0.242 dex for GSP-Phot on the same
stars. The estimates transfer well to external surveys, with mean absolute errors of 0.066 dex for GALAH and 0.068 dex for APOGEE. For open clusters, the median difference between our estimated [Fe/H] and spectroscopic values is 0.041 dex, smaller than both GSP-Phot (0.248 dex) and a previous APOGEE-trained XGBoost model (0.067 dex). Applied to the
Galactic disk, our model recovers a broken thin-disk radial gradient, with inner and outer slopes of $+0.119$ and $-0.058\,\mathrm{dex\,kpc^{-1}}$, respectively, and a break near 5.9 kpc, as well as an open-cluster gradient of $-0.066\,\mathrm{dex\,kpc^{-1}}$; both agree with previous high-resolution spectroscopic studies. Our [Fe/H] estimates are accurate to 0.05-0.07 dex for AFGK
stars with $[\mathrm{Fe/H}]\gtrsim-2.5$; below this limit, the predictions should be treated as lower bounds. The catalogue and trained model are publicly available on Zenodo and are suitable for chemical studies of the Milky Way.
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Quantum Physics
A Reversible Continuous-Variable Photonic Memory Architecture Based on Displacement-Evolved Coherent-State Dynamics
Sanjit Krishna G M
Modern information systems increasingly require
memory architectures capable of storing not only static data but also the
evolution of information over time. While continuous-variable photonic platforms have been extensively studied for
quantum communication and computation, their potential as dynamically evolving
memory systems remains largely unexplored. In this work, we introduce a metadata-assisted continuous-variable photonic
memory architecture in which information is represented by latent vectors encoded across multimode coherent states and updated through reversible displacement operations. The framework combines multimode storage with metadata-based indexing, enabling
navigation and reconstruction of historical
memory states through rollback
retrieval. Unlike conventional approaches that focus on preserving a single
quantum state, the proposed framework treats
memory as a continuously evolving trajectory in continuous-variable phase space. This perspective naturally extends beyond image storage to temporal data streams, machine-learning latent representations, scientific simulations, and other forms of dynamically changing information. Although presented as a theoretical proof-of-concept, the results suggest that continuous-variable photonic systems may provide a promising foundation for future metadata-aware
memory architectures capable of storing, tracking, and reconstructing the history of evolving information.
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High Energy Astrophysical Phenomena
Universal scaling between magnetar field and initial spin period for short gamma ray bursts
Qin-Mei Li, Qi-Bin Sun, Sheng-Bang Qian et al. (+5 more)
The $B_p$–$P_0$ correlation serves as a critical probe of magnetar engine physics. Although this scaling relation has been firmly established for long gamma-ray bursts (lGRBs), systematic investigations for short GRBs (sGRBs) remain absent, leaving the physical differences between the two populations poorly constrained. Here we analyze 33 Swift sGRBs exhibiting prominent X-ray plateaus from newborn millisecond magnetar
spin-down, and derive their initial
spin period $P_0$ and polar
magnetic field $B_p$. sGRB magnetars span $P_0 \in [1.73,\,18.28]\ \mathrm{ms}$ and $B_p \in [0.06,\,2.82] \times 10^{17}\ \mathrm{G}$ ($\langle B_p \rangle = 7.05 \times 10^{16}\ \mathrm{G}$), significantly more magnetized than lGRB magnetars ($B_p \in [0.39,\,23.08] \times 10^{15}\ \mathrm{G}$; $\langle B_p \rangle = 3.69 \times 10^{15}\ \mathrm{G}$). For the first time, we derive consistent power-law $B_p$–$P_0$ correlations for GRBs : the scaling for sGRBs is $\log B_p = (0.84\pm0.07)\log P_0 + (15.79\pm0.07)$, whose slope is highly consistent with that of lGRBs, $\log B_p = (0.83\pm0.09)\log P_0 + (14.92\pm0.06)$. The near-identical slopes imply a universal magnetar
spin-down mechanism, while the vertical offset between intercepts traces divergent progenitor channels. This scaling relation thus offers a new diagnostic to disentangle the formation pathways of GRB. Within the framework of the standard
spin-up model, the mass
accretion rates of sGRBs ($\dot{M} \sim 1 \times 10^{-1}$ to $3 \times 10^{-1}\,M_\odot\,\mathrm{s}^{-1}$) are substantially higher than those of lGRBs ($\dot{M} \sim 10^{-4}$ to $1 \times 10^{-1}\,M_\odot\,\mathrm{s}^{-1}$). Our work completes the missing $B_p$–$P_0$ statistics for sGRBs, quantitatively unifies their magnetar physics with lGRBs, and provides new observational constraints on the origin diversity of relativistic transients.
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All authors Qin-Mei Li, Qi-Bin Sun, Sheng-Bang Qian, Li-Yin Zhu, Fu-Xing Li, Si-Yuan Zhu, Ming Lian, Jing Li
Optics · Cross-listed from eess.SP
Cyclic-Prefix-Free OFDM With Tail-Reuse Reconstruction for Distributed Acoustic Sensing
Ziang Chen, Zhiyang Xue, Zhongxing Tian et al. (+4 more)
Orthogonal frequency-division multiplexing (OFDM) enables frequency-domain reconstruction of the distributed Rayleigh backscatter channel in coherent distributed acoustic sensing (DAS), but an explicitly transmitted cyclic prefix (CP) lengthens the probing period and reduces the slow-time Nyquist limit of each range
cell. We investigate a repeated cyclic-prefix-free OFDM waveform for DAS, in which the tail of the preceding useful block serves as a virtual cyclic extension. A finite-
memory range condition for tail-reuse reconstruction is derived, and circular folding is identified when the useful period is shorter than the channel
memory. For fixed useful-block length and fiber
memory, removing the explicit CP increases the period-limited highest unaliased vibration frequency without changing the occupied-bandwidth-limited spatial resolution. In a 5.2-km numerical configuration, a 75-MSa/s processing rate and a 4096-sample useful block give a 54.61-us probing period and a 9.16-kHz slow-time Nyquist limit. Simulations verify tail reuse, the predicted folding boundary, and recovery of 100 vibration events from 800 Hz to 8800 Hz. Bandwidth-scaling simulations further show that joint processing of fine spatial observations improves differential-phase reliability and reconstruction SNR at a fixed reporting interval. Experiments on a 5.2-km coherent DAS link with 111.984-MHz occupied OFDM bandwidth blindly localize 500-Hz and 3-kHz PZT-induced vibrations at 5063.7 m and 5070.1 m, respectively, and recover their waveforms and spectra. The results demonstrate feasible tail-reuse channel reconstruction and quantify the extension of the unaliased vibration bandwidth.
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All authors Ziang Chen, Zhiyang Xue, Zhongxing Tian, Zeyu Feng, Dongdong Zou, Yi Cai, Huan Huang
Superconductivity
Incommensurate modulation with $Q=0$ A-type Antiferromagnetic Order in CeRh$_2$As$_2$ revealed by NQR studies
Shiki Ogata, Shunsaku Kitagawa, Kenji Ishida et al. (+4 more)
We performed $^{75}$As
nuclear quadrupole resonance (NQR) and
nuclear magnetic resonance (NMR) measurements on a higher-quality single-crystalline CeRh$_2$As$_2$, a heavy-
fermion superconductor exhibiting multiple superconducting (SC) phases under
magnetic fields along the $c$ axis. This SC multiphase is believed to originate from staggered Rashba
spin-orbit coupling associated with locally broken inversion
symmetry. In addition to superconductivity, CeRh$_2$As$_2$ exhibits phase I below $T_0\sim0.5$ K and an
antiferromagnetic (AFM) state below $T_{N}\sim 0.25$ K in the early-stage samples. In the higher-quality sample, the AFM transition becomes more pronounced, and $T_{N}$ increases to nearly coincide with $T_{SC}$. The NQR spectra at the As(1) site imply an internal field with an incommensurate distribution, indicating a two-dimensional incommensurate modulation of the
magnetic structure superimposed on a $Q=0$ A-type AFM component. Moreover, a pronounced decrease in the NQR intensity at $T_0$ well-above $T_{N}$ and an abrupt increase in the internal field at $T_{N}$ suggest the emergence of a slowly fluctuating AFM order at $T_0$ which becomes static at $T_{N}$.
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All authors Shiki Ogata, Shunsaku Kitagawa, Kenji Ishida, Manuel Brando, Elena Hassinger, Christoph Geibel, Seunghyun Khim
Superconductivity
Quadrature magnetoresistance scaling reflects linear field dependence rather than strange metallicity of high-temperature superconductors
D. B. Zhou, Y. Yang, L. F. Feng et al. (+3 more)
The quadrature scaling of magnetoresistance has been widely adopted as a hallmark of the strange metal state. However, whether this scaling signals
quantum criticality or reflects conventional transport behavior remains controversial. Here, by systematically investigating the magnetotransport properties of NiTe2 nanosheets, we demonstrate that the quadrature scaling is not a unique signature of strange
metallicity. We find that the scaling holds only when the crossover field Bc, marking the transition from quadratic to linear magnetoresistance, is sufficiently small relative to the applied field range. Through controlled simulations, we show that the scaling emerges whenever linear magnetoresistance dominates, irrespective of its origin, and fails when the linear regime is inaccessible. This conclusion is supported by observations in SrTiO3 based
heterostructures, where quadrature scaling appears despite the absence of strange metal behavior. Our results establish that the quadrature scaling merely reflects the presence of linear magneto resistance, urging caution in using this scaling as a diagnostic tool for exploring the strange metal state.
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All authors D. B. Zhou, Y. Yang, L. F. Feng, M. F. Zhao, Z. Y. Jia, K. H. Gao
Earth and Planetary Astrophysics
Azimuthal molecular variations in the AB Aur planet-forming disk
Haochang Jiang, Dmitry Semenov, Myriam Benisty et al. (+5 more)
Late infall episodes are emerging as an important driver of disk
evolution. Observed as filamentary streamers in molecular lines and scattered light, such
accretion perturbs disk structures, yet its chemical consequences remain unconstrained. We present NOEMA 1.2 mm observations of AB Aur, a structured young Herbig disk showing evidence for ongoing infall and
planet formation. We detect azimuthal chemical diversity: SO emission is enhanced in the northern disk near the inferred streamer-disk interaction region, while C$_2$H peaks on the opposite southern side; CS forms a nearly axisymmetric ring. HCN and HCO$^+$ peak near the
dust continuum overdensity in the
dust ring. Rotational diagram analyses show higher SO rotational temperatures and column densities in the north, whereas CS remains axisymmetric with lower rotational temperatures, suggesting that the species probe different disk layers. For C$_2$H, temperature variations may contribute to but cannot fully explain the asymmetries. The HCO$^+$/H$^{13}$CO$^+$ line ratio indicates that HCO$^+$ is optically thick across the molecular ring, while the elevated ratio inside the cavity suggests enhanced gas-phase $^{12}$C/$^{13}$C, consistent with isotope-selective photodissociation. Comparison with chemical models favors gas-phase C/O ratios near or above unity, with higher effective C/O in the C$_2$H-bright sector. We discuss two origins for the chemical asymmetries: (i) infall-induced heating and desorption of O-bearing ices enhance SO and lower gas-phase C/O near the streamer's impact site, and (ii)
planet-driven substructures and localized heating or enhanced UV irradiation promote hydrocarbon-rich chemistry in the southern disk. These results highlight that environmental
accretion and
planet formation can jointly imprint azimuthal variations in disk chemistry, with potential impacts on forming
planets' compositions.
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All authors Haochang Jiang, Dmitry Semenov, Myriam Benisty, Vincent Piétu, Thomas Henning, Pablo Rivière-Marichalar, Lucas M. Stapper, Edwige Chapillon
Astrophysics of Galaxies
Examining the stellar-merger origin of the blue main sequence in the open cluster NGC\,3532 with N-body simulations
Khushboo K. Rao and Sambaran Banerjee
Extended main-sequence turnoffs, extended main sequences, and split main sequences observed in the colour-magnitude diagrams of young and intermediate-age
star clusters are now widely interpreted as the consequence of a distribution of
stellar rotation rates among their intermediate-mass (1.5-1.8~M$_\odot$) members. However, the origin of the slowly rotating population that occupies the blue main sequence (bMS) remains uncertain, and
stellar mergers have been proposed as one possible pathway. We investigate whether
stellar mergers can account for the observed bMS population in the 330-Myr
Galactic open cluster NGC 3532. We perform fourteen direct NBODY7 simulations spanning different initial cluster masses, radii, binary fractions, and binary orbital distributions. The simulations are selected to reproduce the present-day properties of NGC 3532 within the observational uncertainties, allowing us to estimate the expected number of merger products among its intermediate-mass main-sequence (MS) members. The cluster hosts $\approx 37\%$ bMS members among its intermediate-mass MS population, which are predominantly slow rotators. Despite this large bMS population, our simulations produce only a handful of MS-MS merger products, due to the cluster's low density and substantial mass loss during its
evolution.
Stellar mergers are unlikely to be the dominant formation channel for the observed slowly rotating bMS population in NGC 3532 and other disperse open clusters. Our results instead favour angular-momentum loss mechanisms operating before or shortly after the zero-age main sequence, such as pre-main-sequence
star-disk interactions or
tidal synchronization in low-mass ratio binaries.
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High Energy Physics (Theory)
Gravitational Memory Beyond Null Infinity through Finite-Distance Carrollian Screens
Felipe Diaz, Sercan Hüsnügil, Oriana Labrin et al. (+1 more)
We investigate gravitational
memory beyond null infinity by studying finite-distance null hypersurfaces endowed with Carrollian geometry. We show that the intrinsic degenerate geometry, optical data, and null Brown–York tensor of a finite null screen define a quasilocal Carrollian dissipative system, providing a natural framework to characterize the residual
geometric response after the passage of radiation. To make this construction explicit and compare it with the standard asymptotic description, we use Robinson–Trautman spacetimes as an exactly solvable radiative setting. For asymptotically flat Robinson–Trautman geometries, we transform the solution to Bondi gauge and extract the asymptotic data directly in terms of the Robinson–Trautman field. In the linearized sector, the Bondi shear is purely electric and produces the standard displacement-
memory effect associated with the relaxation toward the final Schwarzschild geometry. We show that the leading large-radius tracefree component of the finite-screen
memory reduces to the Bondi displacement
memory, while finite-distance corrections retain additional focusing,
embedding dependence, angular drift, Coulombic data, and near-zone information. Thus, Bondi
memory emerges as the universal asymptotic projection of a broader quasilocal Carrollian response. Late-time screens approaching the final Schwarzschild horizon exhibit exponentially decaying non-isotropic Carrollian data, leaving only the isotropic null Brown–York stress. As a by-product, we construct the Robinson–Trautman solution with nonzero cosmological constant to second order in the radiative amplitude and use the
holographic dictionary to study the associated energy fluxes and find that the resulting charge does not obey a universal monotonicity property.
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All authors Felipe Diaz, Sercan Hüsnügil, Oriana Labrin, Leonardo Sanhueza
High Energy Physics (Phenomenology)
A coupled-channel quark model study of possible $\Xi_{cc}^{(*)} K^{(*)}$ molecular states
Ye Yan, Qi Huang, Yuheng Wu et al. (+2 more)
Inspired by the recent experimental discovery of doubly charmed
baryons, we investigate the possible $\Xi_{cc}^{(*)}K^{(*)}$ molecular systems within the framework of the
quark delocalization color screening model. The energy spectra and scattering processes of the relevant
baryon-
meson systems are investigated to explore the dynamical properties of the possible molecular states. The spectrum calculations predict three bound states, namely the $I(J^P)=0(1/2^{-})$ $\Xi_{cc}K$, the $I(J^P)=0(3/2^{-})$ $\Xi_{cc}^{*}K$, and the $I(J^P)=0(5/2^{-})$ $\Xi_{cc}^{*}K^{*}$ molecular states. The scattering phase shift analysis further confirms two $\Xi_{cc}K^{*}$ resonance states with $I(J^P)=0(1/2^{-})$ and $0(3/2^{-})$, which originate from quasi-bound states through channel coupling. In particular, the $I(J^P)=0(1/2^{-})$ $\Xi_{cc}K$ bound state is consistent with previous theoretical studies, making it one of the most promising candidates for future experimental searches.
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All authors Ye Yan, Qi Huang, Yuheng Wu, Hongxia Huang, Jialun Ping
High Energy Physics (Phenomenology)
Production of lepton-flavor-violating scalars through resonant positive-muon annihilation on atomic electrons
Jinhong Shen, Youpeng Wu, Zijian Wang et al. (+10 more)
We investigate an invisible
lepton-
flavor-violating scalar $\phi$ with exclusive $e-\mu$ couplings and study its resonant production via $\mu^+e^-\to\phi$ in fixed-target experiments. Since the effective center-of-mass energy is determined by the momentum of the initial-state bound electrons, atomic effects can significantly affect the resonance behavior. We therefore employ relativistic bound-state electron wave functions to calculate the production cross section and reveal a material-dependent broadening of the resonance lineshape. For the proposed HIAF experiment, fewer than one day of data taking ($6\times10^{10}$ MOT) can probe couplings at the $10^{-5}$ level at 90% confidence level near resonance, demonstrating that high-intensity
muon fixed-target experiments provide a powerful complementary probe of
lepton-
flavor violation.
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All authors Jinhong Shen, Youpeng Wu, Zijian Wang, Leyun Gao, Qite Li, Chen Zhou, Qiang Li, Yu Xu, Xueheng Zhang, Liangwen Chen, He Zhao, Zhiyu Sun, Ruihu Zhu
General Relativity and Quantum Cosmology
Scale-invariant Schrödinger geometry in symmetric teleparallel gravity
Wei-Zhi Liu, Jing-Ying Wang, Shi-Dong Liang et al. (+3 more)
We construct a locally scale-invariant formulation of Schrödinger geometry in symmetric teleparallel
gravity. The unique scale transformation preserving autoparallelism, torsionlessness and the Schrödinger affine structure is first identified, from which a quadratic scale-invariant action is obtained. Using the Palatini formalism, we show that the conditions required for scale invariance are exactly those ensuring that the affine connection is dynamically reduced to the Schrödinger form. Our results establish a direct correspondence between local scale
symmetry and length-preserving affine geometry, providing a new
geometric framework for scale-invariant metric-affine
gravity.
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All authors Wei-Zhi Liu, Jing-Ying Wang, Shi-Dong Liang, Hong-Hao Zhang, Tiberiu Harko, Lei Ming
Astrophysics of Galaxies
Morphology-spin connection in the SAMI Galaxy Survey
Youngmin Baek, Sree Oh, Sukyoung K. Yi et al. (+5 more)
The
spin parameter $\lambda_{\rm{R_e}}$ is a proxy for the specific
stellar angular momentum of
galaxies and is a useful metric for classifying kinematic morphology. This study aims to quantify the relative importance of
galaxy properties in explaining $\lambda_{\rm{R_e}}$, using data from the Sydney-AAO Multi-object Integral-field spectrograph (SAMI)
Galaxy Survey. We apply partial correlation analysis and partial least squares regression to assess the relative contributions of different parameters in explaining $\lambda_{\rm{R_e}}$. We find that morphology indicators, bulge-to-total ratio within one effective radius ($B/T_\rm{e}$) and ellipticity ($\varepsilon_\rm{e}$), show the strongest correlations with $\lambda_{\rm{R_e}}$ and play a leading role in the regression analysis. This result statistically confirms the established fast-rotator sequence, in which fast-rotating early-type
galaxies form a continuous structural and kinematic sequence with spiral
galaxies, with $\lambda_{\rm{R_e}}$ decreasing as bulge prominence increases. The light-weighted age and
stellar mass also exhibit significant correlations, but their contributions are secondary to the morphology indicators in multivariate analyses. We also examine whether the observed trends in $\lambda_{\rm{R_e}}$ can be reproduced using
galaxy properties alone. The morphology indicators (${B/T_\rm{e}}$, $\varepsilon_\rm{e}$) reproduce the overall distribution of observed $\lambda_{\rm{R_e}}$ with a scatter of about 0.12, while the inclusion of Age_LW and $M_\star$ provides only modest additional improvement. However, these relations do not reproduce the slow-rotator regime well. Overall, our results show that photometric structural parameters best explain $\lambda_{\rm{R_e}}$ and suggest that statistical inference of
galaxy spin from non-IFS observables may become feasible with improved models and a broader set of parameters.
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All authors Youngmin Baek, Sree Oh, Sukyoung K. Yi, Scott M. Croom, Matthew Colless, Jesse van de Sande, Stefania Barsanti, Sam P. Vaughan
Plasma Physics
Current-Sheet Formation in Electron Magnetohydrodynamics with Split Fractional Dissipation
Ruimeng Hu, Qirui Peng and Xu Yang
Thin current sheets are central small-scale structures in electron magnetohydrodynamics (EMHD), closely associated with energy dissipation and fast
magnetic reconnection at electron scales. We study their formation numerically in a $2\frac{1}{2}$-dimensional EMHD system on a periodic domain with split fractional dissipation, where the
magnetic potential and the vertical
magnetic component are damped separately. The local theory is governed by a symmetric combined damping balance, but the numerical onset of small-scale growth need not follow this
symmetry. A scaling analysis identifies the out-of-plane current as the primary concentration observable, since it is regularized only through the
magnetic-potential equation. Using a validated
Fourier pseudospectral exponential time-differencing solver with resolution-controlled diagnostics, we find a clear decay/concentration dichotomy. The onset boundary is markedly asymmetric: current-sheet formation appears to be controlled mainly by damping of the
magnetic potential, rather than by the combined damping strength. The analyticity strip collapses to the grid scale, the concentration sharpens under grid refinement, and the observed growth is consistent with an energy-critical self-similar rate, with exponent near three. These experiments indicate that
magnetic-potential damping is the apparent binding constraint for current-sheet concentration, refining the symmetric sum picture.
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High Energy Astrophysical Phenomena
Hong-Yi Zhang, Heng Bian and Zhao-Yu Zuo
Magnetic white
dwarfs can convert
photons into
axions in their strong
magnetic fields, with the conversion probability modulating the light curve as the
star rotates. However, this observable is degenerate with intrinsic
stellar variability if the background is modeled too simplistically. We develop a controlled background-degeneracy framework that computes the
axion-induced modulation from reconstructed
stellar magnetic fields while fitting it simultaneously with a flexible
Fourier model of the intrinsic light curve. Applying this framework to TESS observations of PG~1015+014 using two independent
magnetic field reconstructions, we find that a sinusoidal
stellar background can produce an apparent preference for nonzero
axion-
photon conversion. This preference is absorbed once the background light curve includes the second harmonic, indicating that higher-harmonic
stellar variability is a leading degeneracy for precise photometric
axion searches in
magnetic white
dwarfs. Interpreting the two-harmonic fit as a conservative baseline, we obtain competitive constraints for sub-$\mu\mathrm{eV}$
axions. We further derive an analytic target-ranking estimate for other TESS
magnetic white
dwarfs, identifying systems where phase-resolved
magnetic modeling would be most valuable for competitive
axion probes.
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Adaptation and Self-Organizing Systems · Cross-listed from q-bio.MN
A Reexamination of Noise-Driven Robustness Evolution in Gene Regulatory Networks
Momoko Amemiya and Ayaka Sakata
Gene regulatory network (GRN) models are widely used to investigate gene-expression dynamics in biological systems. In this study, we re-examine an evolutionary GRN model proposed by Kaneko, which was used to investigate the relationship between robustness to nongenetic phenotypic noise and robustness to mutation. We explicitly reconstruct the simulation protocol by specifying computational details omitted from the original study and reproduce its main qualitative findings, including the noise-dependent suppression of low-fitness individuals, the relationship between isogenic phenotypic variance and genetic variance, and the increased robustness of evolved networks under certain expression noise. We further analyze the robustness of evolved populations to variations in initial conditions. While the representative-network analysis shows quantitative differences from the original study, the population-level analysis supports the qualitative conclusion that
evolution under higher phenotypic noise leads to broader basins of attraction. We provide a reusable implementation and publicly release the source code to support reproducibility and facilitate further studies on robustness in dynamical GRN models.
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Quantum Physics
Monogamy inequalities of entanglement of assistance in $2\otimes 2\otimes d$ systems
Xue-Na Zhu, Gui Bao, Zhi-Xiang Jin et al. (+2 more)
The monogamy relations characterize the distribution of
quantum correlations among the multipartite
quantum systems. We study the monogamy relations of the
entanglement of assistance in $2\otimes 2\otimes d$ systems. We present explicitly the relations satisfied by the concurrence, the tangle and the concurrence of assistance, which can be used to derive rigorous monogamy relations. Detailed examples are given to illustrate our results.
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All authors Xue-Na Zhu, Gui Bao, Zhi-Xiang Jin, Shao-Ming Fei, Tao Li