Solar and Stellar Astrophysics
Influence of mass-transfer stability on the formation of post-common-envelope binaries
Yanxu Shi, Hongwei Ge, Zhenwei Li et al. (+9 more)
Post-common-envelope binaries are the natural laboratories for constraining the physics of common envelope
evolution, which is one of the most uncertain phases in binary
stellar evolution. Traditional binary population synthesis models, adopting mass transfer stability criteria based on polytropic
stellar models, systematically overpredict the number of post-common-envelope binaries with
solar-type main-sequence companions. In this work, we present an updated binary population synthesis model using the rapid binary
evolution code Binary
Star Evolution, incorporating a physically motivated mass transfer stability criterion and a self-consistent envelope binding energy prescription. We compile a comprehensive sample of classic white
dwarf + main sequence post-common-envelope binaries with well-measured parameters, hosting both M-
dwarf and A/F/G/K-
stars. We find that the enhanced mass transfer stability is an additional mechanism responsible for the observed dearth of post-common-envelope binaries with
solar-type main sequence companions; neither
magnetic braking nor selection effects alone can fully account for this deficit, and a combination of all three processes is most likely required. Models with inefficient common envelope
evolution ($\alpha_{\rm CE}=0.25$) provide the best overall match to the observed population. These results highlight the critical role of MT stability in shaping the observed post-common-envelope binaries population and provide new constraints on common envelope
evolution.
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All authors Yanxu Shi, Hongwei Ge, Zhenwei Li, Diogo Belloni, Rizhong Zheng, Dengkai Jiang, Hailiang Chen, A. Santos-Garcia, Santiago Torres Gil, Alberto Rebassa-Mansergas, Xuefei Chen, Zhanwen Han
Chemical Physics
Reaction-Network-Level Discovery of Ammonia Synthesis Catalysts via Ten-Million-Scale Generative Exploration
Ruili Li, Rui Qi, Shuoqi Zhang et al. (+5 more)
Catalyst discovery for ammonia synthesis is inherently a reaction-network challenge because catalytic performance is governed not by a single adsorbed intermediate, but by a surface's orchestrated compatibility with multiple distinct intermediates across competing dissociative and associative pathways. However, navigating ultra-large chemical spaces under such multi-intermediate constraints remains a formidable bottleneck for conventional screening workflows. Here, we report a reaction-network-level catalyst discovery framework driven by ten-million-scale generative exploration. By coupling adsorbate-specific generative
Transformers with high-throughput machine learning potentials, we systematically map the structure-property landscapes of four critical intermediates (N*, NH*, NNH*, and HNNH*). Scale-dependent overlap analysis shows that the full four-intermediate compatibility space remains strongly under-sampled at conventional 105-106 generative scales, emerging exclusively under ten-million-scale exploration. By generating approximately 15 million configurations per adsorbate, followed by structural compression and machine-learning-potential predictions, we identified 279 highly potential target materials. This sparse compatibility space successfully recovers traditional Fe- and Ru-based motifs while uncovering previously unexplored catalyst families. Representative DFT calculations validate pathway-dependent mechanisms: Fe-V emerges as a dissociative-pathway lead by significantly lowering the initial N2 dissociation barrier, whereas Al-Pd-Zr efficiently stabilizes associative intermediates as an associative-pathway lead. These findings establish multi-intermediate reaction-network compatibility as a robust criterion for discovering advanced catalysts from multi-million generative chemical spaces.
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All authors Ruili Li, Rui Qi, Shuoqi Zhang, Qingli Tang, Qingqing Mao, Ritankar Das, Beien Zhu, Yi Gao
Optics
Chaos Generation and Control with Molecular Optomechanical System
Hui-Hui Xu, Jian-zhuang Wu, Lei-Bo Deng et al. (+2 more)
Chaos is central to secure communication and physical random-number generation. Conventional cavity-optomechanical implementations, however, usually rely on weak single-
photon optomechanical coupling and low-frequency mechanical modes, so access to deterministic chaotic dynamics often requires large driving power and careful suppression of thermal noise. Here we theoretically study a hybrid molecular optomechanical system formed by coupling a plasmonic nanocavity to a whispering-gallery-mode (WGM) microcavity. The plasmonic nanocavity provides terahertz-scale single-
photon optomechanical coupling to a molecular vibration, while the WGM resonator offers a low-loss photonic channel that mitigates the short plasmon lifetime. By integrating the semiclassical equations of motion and evaluating the largest Lyapunov exponent, we map the nonlinear dynamical regimes in the parameter spaces of WGM detuning, plasmon–WGM coupling, and plasmon–vibration optomechanical coupling. We show that increasing the plasmon–vibration coupling drives the system from self-sustained oscillations to chaos through a period-doubling cascade. At moderate coupling strengths, isolated chaos windows can be opened or closed by tuning the WGM detuning and the inter-cavity coupling. These results identify molecular optomechanics as a controllable room-temperature platform for on-chip chaotic light generation and random-signal applications.
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All authors Hui-Hui Xu, Jian-zhuang Wu, Lei-Bo Deng, E Wu, Yong-Hong Ma
High Energy Astrophysical Phenomena
Are most detected tidal disruption events partial?
Megha Sharma, Daniel J. Price, Alexander Heger et al. (+1 more)
During a
tidal disruption event (TDE), a
star loses mass due to the
tidal gravitational forces of the black hole. In a partial
tidal disruption event, a
stellar remnant is left behind. Several dozen TDEs have been detected so far, including repeating partial events. We use the Phantom smoothed particle hydrodynamics code to model the disruption of a 1 Msun
star around a 10^6 Msun black hole for impact parameters resulting in less than equal to 50 % mass loss. We only consider zero energy orbits. Our simulations show that the mass fallback rate can exceed the Eddington limit for beta greater than or equal to 0.8, allowing debris to obscure the
accretion disc by forming a reprocessing layer, similar to full TDEs. The mass fallback rate is shallower than t^{-5/3}, tracking closer to t^{-9/4}. Assuming thermal emission from the debris, that shock heating is trapped, that electron scattering dominates the opacity, and a color correction f_{col} of 1.7, we find temperatures of ~10^4 K, optical bolometric luminosities of ~ 10^{42-44} erg/s and blackbody radii ranging from 10-100 au for our simulations. We compare our values with observations and find support for the previous argument that some TDEs classified as full disruptions might actually be partial. Moreover, our results explain the detected optical/UV TDEs. We also find that our zero energy partial TDEs have properties similar to the repeating partial TDEs such as ASSASN-19dj, ASSASN-14ko, ASSASN-18ul, ASSASN-22ci, AT2020vdq and AT2022dbl. In the beta=0.8, isentropic simulation where radiation is assumed to escape, we find X-ray luminosities of ~ 10^{44-45} erg/s and radii lower than the inner most stable circular orbit.
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All authors Megha Sharma, Daniel J. Price, Alexander Heger, Katie Auchettle
Soft Condensed Matter
Hydrodynamic Phase Separation and Morphological Evolution in Chiral Active-Passive Mixtures
Mayurakshi Deb and Rajesh Singh
The collective behavior of passive particles within
chiral active matter has emerged as a significant area of soft matter research. However, most existing studies focus on systems where chirality is imposed by external torques rather than intrinsic activity. In this work, we study emergent dynamics in a suspension of active spinners and passive colloids by computing many-body hydrodynamic interactions via Ewald summation. By systematically exploring a broad range of area fractions and rotational velocities, we identify distinct phase-separation regimes sensitive to the system's kinematic parameters. Specifically, we report the emergence of unique structural morphologies, including the formation of passive particle
vortices surrounding phase-separated active spinners and the development of large-scale active-passive bands. We characterize the underlying dynamics by analyzing the temporal
evolution of characteristic length scales and the non-
equilibrium velocity distributions of the passive particles. Our findings provide new insights into the role of long-range hydrodynamic couplings in governing the self-organization of non-
equilibrium condensed matter.
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High Energy Physics (Phenomenology)
Praveen Bharadwaj, Utpal Chattopadhyay, Dilip Kumar Ghosh et al. (+1 more)
The Diffuse
Supernova Neutrino Background (DSNB), an isotropic flux arising from the cumulative
neutrino emission of all
stellar core-collapse events throughout
cosmic history, is expected to be detected by next-generation
neutrino observatories. As DSNB
neutrinos propagate over cosmological distances through the
cosmic neutrino background (C$\nu$B), they may undergo non-standard
neutrino self-interactions ($\nu$SI), leaving distinct spectral imprints on the observed flux. In this work, we investigate the impact of scalar ($\phi$)-mediated $\nu$SI on the DSNB within a full three-
flavor framework that retains the complete PMNS structure. We consider four representative
flavor-diagonal coupling structures–universal, $e$-, $\mu$-, and $\tau$-specific. The resonant scattering $\nu_i\nu_k\to\phi\to\nu_j\nu_l$ off the lightest, relativistic C$\nu$B state produces broad spectral depletion whose pattern depends on the coupling structure and the
neutrino mass ordering, generating distinctive signatures across the six
flavor fluxes. We compute the resulting event spectra at JUNO, Hyper-Kamiokande with gadolinium loading, and DUNE, and derive projected $3\sigma$ sensitivities in the $(m_{\phi},~g)$ parameter plane. We find that these experiments can probe couplings as low as $g\sim10^{-8}$ for $m_\phi\sim100$–$300$ eV, surpassing existing bounds by up to a few orders of magnitude in the sub-100 eV mass range. Moreover, unlike the
flavor-blind cosmological and
supernova bounds, the DSNB sensitivity is
flavor-discriminating, offering a unique opportunity to identify the underlying
flavor structure of $\nu$SI in the event of a detection.
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All authors Praveen Bharadwaj, Utpal Chattopadhyay, Dilip Kumar Ghosh, Arnab Sarker
Materials Science
Coherent seeding and control of dynamical ferroelectricity by phonon anharmonicity
Junhan Huang, Yongkang Ju, Xinbo Wang et al. (+12 more)
Optical control of
quantum materials has progressed along two separate directions: creating non-
equilibrium states inaccessible at
equilibrium, and coherently controlling ultrafast dynamics with multi-pulse protocols. Ferroelectricity is especially attractive in this context because its order parameter, macroscopic polarization, directly links inversion-
symmetry breaking to functional response. Yet light-induced ferroelectricity has so far been confined to
quantum paraelectrics near the ferroelectric instability, where critical fluctuations obscure the formation of a homogeneous ferroelectric state and complicate its deterministic coherent control. Unifying these capabilities – preparing a
symmetry-broken state and then coherently steering its functionality – remains a central challenge. Here we show that intense terahertz excitation of a soft
phonon mode induces a ferroelectric state in centrosymmetric PbTe, a thermoelectric material with strong
lattice anharmonicity but no ferroelectric transition at finite temperature. The light-induced
symmetry-broken state can be realized up to about 100 K, without relying on local dipolar fluctuations. Experiment and theory together reveal that terahertz-driven anharmonic coupling between degenerate transverse optical
phonons underlies this ferroelectric induction. Furthermore, we demonstrate coherent amplification and suppression of the induced polarization via a double-pulse-excitation protocol. These results establish terahertz-driven anharmonic mode coupling as a general strategy for controlling mode-mediated functionalities in
quantum materials, opening a route to ultrafast information processing.
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All authors Junhan Huang, Yongkang Ju, Xinbo Wang, Li Yue, Hao Wang, Qiaomei Liu, Tianchen Hu, Yuchen Cui, Liyu Shi, Shangfei Wu, Sijie Zhang, Dong Wu, Peizhe Tang, Tao Dong, Nan-Lin Wang
Solar and Stellar Astrophysics
X-shooter spectroscopy of giant stars in the nuclear star cluster
L. Origlia, C. Fanelli, A. Mucciarelli et al. (+5 more)
Near-IR spectra of a homogeneous sample of 15 red
giants in the
Galactic nuclear star cluster, within 1.5 pc of SgrA*, have been acquired with X-shooter at the Very Large
Telescope. From these spectra line-of-sight radial velocities and chemical abundances of iron, carbon, oxygen and other alpha and light elements have been derived. By combining radial velocities from this study and proper motions from the literature we computed the orbits of these
stars, finding that they have been confined within 12 pc from SgrA* for their entire lifetime, thus strongly suggesting an in-situ formation and
evolution. Iron abundances between half and twice
solar, about
solar-scaled values within +/-0.1 dex for {\alpha} elements, Ti and V, some enhancement of [Na/Fe], [K/Fe] and [Al/Fe] and some depletion of [C/Fe] with respect to the
solar ratios have been measured. The inferred chemical abundance distributions are consistent with a formation from a gas enriched by both type II and type I SNe over a prolonged timescale, closely matching those of the metal-rich populations of the inner bulge field and other complex
stellar systems like Terzan 5 and Liller 1.
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All authors L. Origlia, C. Fanelli, A. Mucciarelli, R. M. Rich, M. Schultheis, N. Ryde, B. Thorsbro, T. Fritz
Materials Science
Interfacial melting as a thermodynamic indicator of solid-state synthesizability
Zihan Zhang, Mengyi Chen, Qianxiao Li et al. (+1 more)
Computational materials discovery commonly ranks candidate materials by their thermodynamic stability on the formation energy convex hull, yet many predicted-stable phases resist synthesis. We propose that solid-state synthesizability through interfacial-melt-mediated routes requires an additional thermodynamic condition: the interfacial melt at the target composition must itself remain locally stable against spinodal decomposition. We examine this in the classical Fe–B system, where thermodynamically stable FeB$_4$ has been reported under high-pressure synthesis but not in low-pressure synthesis attempts. Using melt–quench molecular dynamics driven by a fine-tuned machine-learning interatomic potential, we find that, at ambient pressure, the B-rich interfacial melt near the FeB$_4$ composition develops a concave free-energy landscape, signaling a demixing instability that is corroborated by the concentration–concentration structure factor and correlated with low-energy icosahedral and pentagonal-pyramidal boron motifs. In contrast to FeB$_4$, metastable Fe$_3$B and Fe$_{23}$B$_6$ remain synthesizable because their corresponding melts are stable. Applied pressure introduces a convex $PV$ contribution that strongly suppresses this instability, reducing the
curvature at the FeB$_4$ composition to within the uncertainty of our fit at 1800~K, consistent with the experimental synthesis boundary. Comparison with CrB$_4$ further shows that weaker melt instability correlates with easier experimental synthesis. Interfacial-melt stability, which atomistic simulations can assess via the low-$k$ concentration–concentration structure factor, is thus proposed as a practical thermodynamic screening descriptor of synthesizability for AI-assisted materials discovery.
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All authors Zihan Zhang, Mengyi Chen, Qianxiao Li, Peichen Zhong
High Energy Astrophysical Phenomena
Testing the Generalization and Domain Stability of Compact Feature Representations for Photometric Supernova Classification
Anurag Garg
Photometric classification of
supernovae increasingly requires models that are not only accurate within a single survey but also robust to changes in cadence, noise properties, filter coverage, and survey domain. We investigate the generalization and domain stability of a compact 16-feature representation for Type Ia
supernova classification. The feature set consists of physically interpretable descriptors of brightness, color, variability, and temporal
evolution. Using the
Supernova Photometric Classification Challenge (SPCC)
dataset as the reference domain, we confirm that a compact XGBoost classifier achieves strong within-survey performance, reaching an F1 score of 0.844 and a PR-AUC of 0.928 on a held-out test set. We then evaluate robustness under alternative classifiers, repeated resampling, feature perturbations, missing-band proxies, shortened temporal coverage, and cross-survey transfer to PLAsTiCC. The compact representation remains stable under resampling and moderate perturbations, but direct SPCC$\rightarrow$PLAsTiCC transfer produces a substantial performance degradation. Class-conditional centroid analysis shows that the SPCC and PLAsTiCC Type Ia populations occupy different regions of the compact feature space. The cross-survey Ia centroid shift exceeds the Ia/non-Ia separation within either survey, indicating that the transfer gap is driven primarily by feature-space domain shift rather than classifier instability. These results show that compact physically interpretable features are robust within a survey and useful for diagnostic analysis, but are not automatically survey-invariant. Cross-survey deployment therefore requires feature harmonization, domain adaptation, or restriction to a smaller set of survey-stable features.
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High Energy Physics (Phenomenology)
Twisting Small-$x$ Gluon Tomography with Orbital Angular Momentum
Wei Kou and Xurong Chen
We propose an orbital-angular-momentum-resolved extension of small-$x$
gluon tomography in hard diffractive dijet deep inelastic scattering. In the standard plane-wave setup, the
elliptic correlation between the dijet relative momentum and the target
recoil probes the
elliptic component of the small-$x$
gluon Wigner distribution through a fixed transverse readout. We show that replacing the plane-wave
lepton current by a twisted wave-packet current promotes this readout into a tunable OAM–Bessel projection kernel. The exchanged virtual
photon is not treated as an asymptotic
vortex particle; the OAM dependence enters through the transverse structure of the
lepton electromagnetic current. The resulting observable is a family of $M$-resolved
elliptic correlations $A_2^{(M)}(q_T,R_\gamma)$, where $q_T$ denotes the transverse Bessel scale of the projection kernel, not the transverse momentum of the exchanged
photon. We derive the normalized linear response and show that it contains a subtraction from the deformation of the total diffractive rate. Consequently, the
elliptic response can vanish while the diffractive rate remains finite. This finite-rate null is a normalized projection zero of the response to the target
elliptic gluon component, not a disappearance of diffraction. It is not available as a tunable mode zero in the standard single plane-wave readout, and provides an external projection basis in which the response to the same small-$x$
elliptic geometry can be probed with either sign or tuned to zero.
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Geophysics
Tensor Train Decomposition-based 3D Implicit Full Waveform Inversion with Multi-scale Structural Similarity
Liangsheng He, Chao Song, Tiansheng Chen et al. (+2 more)
Three-dimensional full waveform inversion (3DFWI) is a powerful technique for reconstructing high-resolution subsurface velocity models. However, its application is often limited by high
memory requirements, computational costs, and sensitivity to cycle skipping. To overcome these challenges, we propose a novel tensor train (TT) decomposition-based 3D implicit full waveform inversion framework (TT-3DIFWI) combined with a multi-scale structural similarity (M-SSIM) objective function. In this framework, the 3D velocity model is represented by TT decomposition as a product of a series of low-rank core tensors. Then, three axis-specific implicit neural network representations (INR) based on one-dimensional vector coordinates as input are constructed to predict these core tensors, rather than directly predicting the velocity model. This INR reparameterization method based on TT decomposition can significantly reduce the
memory consumption of INR training while maintaining the accuracy and resolution of the 3D velocity model reconstruction. Meanwhile, the low-rank structure of TT decomposition also ensures the structural consistency of the reconstruction velocity, thereby improving the accuracy and continuity of the inversion result. Furthermore, the M-SSIM objective function can compare the multi-scale structural differences between predicted and observed data, and utilize the ultra-low frequency features to reduce cycle skipping. Numerical experiments on synthetic and challenging land
datasets demonstrate that TT-3DIFWI with M-SSIM achieves accurate and continuous velocity reconstruction, even with poor initial models or missing low-frequency data.
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All authors Liangsheng He, Chao Song, Tiansheng Chen, Tao Liu, Cai Liu
High Energy Physics (Phenomenology)
A novel approach for studying two-particle momentum correlation function in relativistic nuclear collisions
Zhi-Lei She, Wen-Chao Zhang, An-Ke Lei et al. (+7 more)
Two particle momentum correlation functions provide a nontrivial tool for probing the strong interaction and/or extracting particle emission source information in relativistic
nuclear collisions. Although transport models can describe the microscopic phase-space
evolution of the collision system, calculating correlation functions within the framework of transport models remains challenging. In this paper, we employ the mixed-event technique to calculate two particle momentum correlation function as $C(k^*)= \mathcal{N} \xi(k^*)\frac{N_{\mathrm{same}}(k^*)}{N_{\mathrm{mixed}}(k^*)}$ based on the parton and
hadron cascade model PACIAE simulated final hadronic state (FHS) with introducing a modification factor $\xi(k^*)$ to improve the treatment of final-state interactions and
quantum statistics effects in the PACIAE model. The simulated results show good agreement with the ALICE data for $Kp$, $pp$, $p\Lambda$, and $\Lambda\Lambda$ momentum correlation functions in $pp$ collisions at $\sqrt{s}=7$ TeV. On the other hand, the particle emission source radius of the correlated pairs are also evaluated based on the simulated FHS self-consistently. Since the PACIAE model employs
hadron-
hadron cross sections derived from the additive
quark model, the calculation of two-particle momentum correlation functions does not require prior assumptions about the interaction between the two correlated particles. This successful “PACIAE + modification factor" approach may shed light on the future study of momentum correlation functions for dimesons, dibaryons, and even diexotic
hadrons.
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All authors Zhi-Lei She, Wen-Chao Zhang, An-Ke Lei, Dai-Mei Zhou, Hua Zheng, Li-Lin Zhu, Qiang Wang, Yu-Liang Yan, Zhong-Qi Wang, Ben-Hao Sa
Optics
Free-Running Waveguide-Integrated Single-Photon Avalanche Detectors for Visible Light
Aswin Alexander, Anirudh R. Ramaseshan, Soe M. Thar et al. (+4 more)
Waveguide-integrated single-
photon avalanche detectors (SPADs) are essential components of integrated photonics platforms for scalable extreme-low-light applications without the use of cryogenics. Here, we demonstrate an integrated SPAD for visible light operating at room temperature in a free-running mode without gating. The device is based on a doped silicon diode end-fire-coupled to a silicon nitride (SiN) photonic integrated
circuit (PIC). We investigate a range of lateral and vertical doping profile designs, and operate the devices with a simple current-mode passive quenching
circuit. The optimal device is a laterally-doped p-i-n+ SPAD with a maximum
photon detection efficiency (PDE) of 1.95 +/- 0.32% for input light at 685 nm wavelength, when reverse-biased at an excess of 1.5 V beyond the breakdown voltage of 15.0 V. We identify promising avenues for improving device performance, which would enable such integrated SPADs to be an attractive choice for cutting-edge integrated photonics solutions in
quantum technologies, low-light imaging, and high-speed communications at visible wavelengths.
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All authors Aswin Alexander, Anirudh R. Ramaseshan, Soe M. Thar, Thomas Y. L. Ang, Jing Zhou, Alexander Ling, Victor Leong
Instrumentation and Methods for Astrophysics · Cross-listed from cs.AI
AI Scientists as Engines of Discovery: A Case for Development within Reformed Institutions
Raul Jimenez, Boris Bolliet, Francisco Villaescusa-Navarro et al. (+7 more)
Agentic artificial intelligence (AI) systems are beginning to assist, accelerate, and partially automate scientific discovery, performing tasks that span literature synthesis, code generation, data analysis, hypothesis proposal, and model criticism. We argue that this transition is qualitative rather than incremental, and that suitably designed multi-
agent systems may evolve from passive computational tools into “AI scientists” that can expand the hypothesis-generating and verification capacity of science. Such systems must be developed and deployed within a scientific ecosystem fit for purpose: institutions must be redesigned for verification, accountability, interpretability, and dual-use safety. We sketch how multi-
agent architectures, illustrated by the prototype framework Denario, accelerate the discovery cycle and traverse model spaces beyond human reach; examine what this implies for authorship, peer review, and the enduring role of human scientists; and close with recommendations for governing AI as an epistemic actor rather than a mere instrument.
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All authors Raul Jimenez, Boris Bolliet, Francisco Villaescusa-Navarro, Rabih Zbib, Benjamin Wandelt, David N. Spergel, Thomas Meier, Jessica Montgomery, Hana Aliee, Licia Verde
Optics
Low-threshold efficient N${_2^+}$ lasing driven by sub-cycle soliton dynamics in a hollow waveguide
Tiandao Chen, Zhiyuan Huang, Jinyu Pan et al. (+12 more)
The phenomenon of N${_2^+}$ lasing, observed in femtosecond-
laser filamentation, attract considerable interests in recent several years, with great application potentials in fields of remote sensing and ultrafast spectroscopy. Efficient N${_2^+}$ lasing at relatively-low pump energies and with high beam quality, while being highly-demanded for applications, remains, however, quite challenging in practical experiments. Here, we demonstrate a new route of generating low-threshold N${_2^+}$ lasing with unprecedently-high efficiency, which is enabled by
soliton dynamics in a gas-filled hollow-tapered-capillary system. High-order-
soliton compression of a 12-fs, 10-${\mu}$J-level pump pulse forms a sub-cycle asymmetric transient that tunnel-ionizes N${_2}$ to N${_2^+}$ and, through direct, single-
photon resonant excitation, creates population inversion between the ground state ${X^2\Sigma_g^+}$ and the excited state ${B^2\Sigma_u^+}$${-}$a dynamic process distinct from the widely adopted three-state coupling picture${-}$and remarkably at unexpectedly low pump energy. In the experiments, we obtained 100-nJ-level N${_2^+}$ lasing pulses at 391 nm with conversion efficiencies up to 3.3$\times$10$^{-3}$, at pump energies of less than 50 ${\mu}$J. These results represent improvement of more than one orders of magnitude in both generation efficiency and lasing threshold, compared with prevailing filamentation-based schemes. Our study bridges two generally-disparate fields (sub-cycle
soliton dynamics and N${_2^+}$ lasing), and paves the way for narrow-band, high-beam-quality lasing pulses that may find wide applications in advanced spectroscopy and nonlinear pump-probe experiments.
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All authors Tiandao Chen, Zhiyuan Huang, Jinyu Pan, Donghan Liu, Pengtao Wang, Xinglin Zeng, Jinxin Zhan, Jiapeng Huang, Wenbin He, Xin Jiang, Huailiang Xu, Yi Liu, Meng Pang, Yuxin Leng, Ruxin Li
High Energy Physics (Phenomenology)
Remarks on atmospheric effect of D-foam in light of muon puzzle
Chengyi Li
In our recent paper~[1], we used a stringy model for
quantum space-time foam to suggest that the so-induced subluminal Lorentz violation~(LV) for
photons would not lead to experimentally unacceptable changes in the developments of particle showers initiated by
cosmic $\gamma$-rays in the Earth's atmosphere, in contrast to other approaches to LV. The result indicated, nonetheless, at the same time that the foam can mildly modify the electromagnetic cascades under certain conditions, by suppressing pair creation on
nuclei by primary
photons. In this addendum, we consider how this modification affects the detection of extensive air shower~(EAS) initiated by an ultrahigh-energy
cosmic-ray particle~(viz., a primary
hadron), like
proton with $E \sim 10^{19}~\textrm{eV}$, given that secondary
photon subshowers following $\pi^{0}$ decays could be similarly influenced. We argue that fewer electrons would reach the detector and hence the energy of the primary particle may be underestimated due to foam effects, enhancing in such a way the
muon content in EASs. This opens up the possibility of interpreting the alleged “excess” of
muons, as reported by Auger and
Telescope Array collaborations recently and many other experiments on high-energy
cosmic rays, with a
quantum-gravitational effect. Future observations are anticipated to confirm whether this anomaly really exists.
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Quantum Physics
Bunny Codes: Broadening Superconducting Quantum Error Correction Capability through Advanced Control Engineering
Runshi Zhou, Xingye Yuan, Linghang Kong et al. (+4 more)
Drawing on advances in superconducting
qubit control schemes that unlock enriched native gate sets at the hardware level, we systematically examine how harnessing this enlarged physical two-
qubit gate pool—specifically CNOT and CXSWAP—streamlines syndrome extraction for certain qLDPC codes with nonlocal stabilizers. Through an exhaustive search, we discover a set of qLDPC codes with various stabilizer weights and distances that can be implemented on the two-dimensional nearest-neighbor
qubit connectivity native to superconducting hardware while achieving performance equivalent to that of the direct CNOT implementation requiring long-range interactions. We refer to those codes as Bunny codes. Across all code distances we examine, the best Bunny codes with weight-6 stabilizers in periodic boundary conditions have a code rate approximately $3\times$ that of the toric code; when converted to open boundary conditions, they retain an approximately $2\times$ code rate advantage over the rotated surface code. In
circuit-level simulation, we find that some Bunny codes exhibit logical error rates an order of magnitude lower than toric codes with comparable code rates. Our results demonstrate that high-performance
quantum error correction can be achieved using an expanded gate set rather than long-range couplers, thereby significantly reducing hardware complexity.
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All authors Runshi Zhou, Xingye Yuan, Linghang Kong, Fang Zhang, Kai Zhang, Zhaohui Yang, Jianxin Chen
Materials Science
Thermal Transport in SiC with Intrinsic Defects and Mg Transmutation Products
Chen Shen, Yang Su, Maciej P. Polak et al. (+5 more)
Silicon carbide is a leading candidate material for advanced
nuclear energy systems, but irradiation-induced defects and transmutation products can severely degrade its thermal conductivity. In fusion environments, Mg is predicted to be a major solid transmutant in SiC, yet it is not well understood how different Mg-related defects affect
phonon transport. Here, we develop a machine-learning interatomic potential, MLIP4SiC-Mg, for 3C-SiC containing intrinsic point defects, Mg-related defects, and Mg-defect complexes. The potential is trained on a large DFT
dataset and reproduces DFT energies, forces, equation-of-state behavior,
phonon dispersions, and
lattice thermal conductivities with near-DFT accuracy. Combined with Green-Kubo molecular dynamics, force-error correction, and a resistance-based treatment for dilute defective systems, MLIP4SiC-Mg enables quantitative thermal-conductivity calculations in large defective supercells. The corrected thermal conductivity of pristine 3C-SiC is 421 W/(mK) at 300 K, in good agreement with available experimental data. All defects considered strongly reduce thermal conductivity, but their scattering strengths are highly configuration dependent. V_C and Mg_TC act as strong
phonon scatterers, whereas isolated Mg_Si is comparatively weak. Residual thermal resistivity analysis shows that defect-induced thermal resistance is not strictly linear with concentration and should be treated as an effective temperature- and concentration-dependent scattering metric. Mg_Si-V_C clustering enhances scattering relative to isolated Mg_Si, but reduces the total excess resistance relative to spatially separated Mg_Si and V_C defects. These results clarify the configuration-dependent role of Mg transmutation in irradiation-degraded SiC and provide an atomistic framework for quantifying defect-controlled heat transport in
nuclear ceramics.
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All authors Chen Shen, Yang Su, Maciej P. Polak, Rafi Ullah, Nuohao Liu, Mary Alice Cusentino, Dane Morgan, Izabela Szlufarska
High Energy Physics (Theory)
Extended Thermodynamics and Renyi Entropy Beyond Fixed Central Charge
Chatchai Promsiri, Phuwadon Chunaksorn, Ratchaphat Nakarachinda et al. (+1 more)
An outstanding problem in the framework of conformal thermodynamics concerns the interpretation of variations in the central charge $C$. In this paper, we construct a novel central-charge Rényi
entropy via the Casini-Huerta-Myers (CHM) map by considering thermal CFTs on a
hyperbolic cylinder within a fixed charge, field theory volume and central charge potential $(\tilde{Q},\mathcal{V},\mu_C)$ grand canonical ensemble. We demonstrate that the resulting
entropy satisfies all four fundamental Rényi
entropy inequalities throughout the admissible range of $\mu_C$, establishing its consistency as a genuine Rényi measure. Physically, this novel measure extends conventional Rényi
entropy by capturing the degree of
entanglement across a statistical ensemble of
holographic CFTs with fluctuating degrees of freedom. Furthermore, our conformal thermodynamic analysis of near-extremal configurations reveals that residual
entropy arises from the central charge sector rather than thermal excitations. The mass gap that separates the extremal state and the first thermal excitation introduces a characteristic temperature scale $\tilde{T}_*$, which translates via the CHM map into a distinguished characteristic Rényi index $n_*$. Crucially, we propose that $n_*$ separates the theory space into two qualitatively distinct statistical regimes: a dominant-theory regime ($n > n_*$) governed by the most probable CFT realizations, and a multi-theory regime ($n < n_*$) where a broader spectrum of fluctuating theories and higher-energy modular excitations becomes increasingly relevant.
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All authors Chatchai Promsiri, Phuwadon Chunaksorn, Ratchaphat Nakarachinda, Ekapong Hirunsirisawat
Fluid Dynamics
Non-monotonic variations in pressure drop and chaos in viscoelastic fluid flows through an ordered microporous medium
A. Chauhan and C. Sasmal
Several recent experimental studies have revealed non-monotonic variations in elastic
turbulence-induced chaotic flow behaviour and pressure drop during the flow of viscoelastic fluids through a microporous medium. The present numerical study aims to investigate and hypothesise about the physical mechanisms governing these complex flow behaviours in an ordered microporous medium consisting of cylindrical micropillars arranged in a staggered configuration. We propose that birefringent strands of high elastic stress, generated by the stretching and
alignment of
polymer molecules within the porous structure, play the dominant role in controlling the non-monotonic variations in chaos and pressure drop. At low Weissenberg numbers, these stress strands develop gradually, mainly downstream of the micropillars, whereas beyond a critical Weissenberg number, they begin to fluctuate strongly, leading to chaotic flow dynamics. However, at even higher Weissenberg numbers, the strands become larger and stronger, eventually interconnecting between neighbouring micropillars, causing the flow to reorganise into a nearly steady, ordered state similar to that observed at low Weissenberg numbers. On the other hand, the pressure drop in the system consists of a mean contribution, obtained from statistically stationary flow quantities, and a fluctuating contribution. While the mean component increases monotonically with the Weissenberg number, the fluctuating component varies non-monotonically, leading to a similar trend in the total pressure drop. Moreover, the non-monotonic chaotic behaviour strongly depends on the solid volume fraction of the porous medium, which alters both the critical Weissenberg number for instability onset and the range over which the non-monotonic behaviour persists.
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Astrophysics of Galaxies
Observations of a Possible Transient Magnetically Arrested Accretion State in a Nearby Quasar: OQ208
Brian Punsly, Cormac Reynolds, Paola Marziani et al. (+12 more)
OQ208 is a nearby, partially obscured
quasar (z=0.077) that is a young, bright, parsec scale
radio source. We assemble archival and new high frequency VLBA and VLA observations and optical spectra to form a data-set spanning 39 years.
Radio light curves covering 58 years were also compiled. We utilize new spectrophotmetry to calibrate previous spectroscopy using forbidden narrow lines that are expected to be stable on much longer time scales. VLBA and VLA observations of a light-year scale bright
nuclear flare at 15.4~GHz and 22~GHz reveal a rise (fade) beginning in mid-1996 (early-2000). Quasi-contemporaneously, from 2/7/1997-6/3/2000, the H$\alpha$ broad line equivalent widths (EWs) and fluxes dropped dramatically. In the context of the tendency of
radio loud
quasars to have a depressed extreme ultraviolet (EUV) continuum (the main source of ionizing flux for H$\alpha$) relative to
radio quiet
quasars at matched UV luminosity (the EUV deficit of
radio loud
quasars), this may not be a coincidence. Analytic models previously developed to explain the relationship between jet power and the EUV deficit are consistent with (but not direct observational proof of) the small EWs being a consequence of transient magnetically arrested
accretion states from $\sim1997-2001$. The 22 GHz VLBA
nucleus gradually fades, in 2023 the flux density is $<5\%$ of its value in 2000. The environs of the
nucleus also fade at 22 GHz, but in a time delayed fashion.
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All authors Brian Punsly, Cormac Reynolds, Paola Marziani, Gary J. Hill, Alexander B. Pushkarev, Carlo Stanghellini, Frank Schinzel, Christopher O'Dea, Gregory R. Zeimann, Andrew Biggs, Jian-Min Wang, Pu Du, Alberto Floris, Mauro D'Onofrio, Levi Malmstrom
Quantum Physics
When the Learning With Errors Problem Meets the Coherent Ising Machine: A Penalty-Free Algorithm-Hardware Co-Design
Shuxian Jiang
The Learning With Errors (LWE) problem constitutes the mathematical foundation of modern Post-
Quantum Cryptography (PQC). Cryptanalysis of LWE ranges from classical
lattice reduction to machine learning and
quantum-classical hybrids. We propose CIM-BDD, a hybrid Bounded-Distance-Decoding solver that reduces LWE to a Quadratic Unconstrained Binary Optimization (QUBO) problem through a strictly penalty-free mapping. An algebraic elimination of the secret embeds LWE into a $q$-ary
lattice, absorbing the modular arithmetic and recasting the problem as a Closest Vector Problem (CVP). The squared error norm is then used directly as the QUBO energy, so the cryptographic noise is the objective to be minimized rather than a penalized constraint. To realize this general model on current Noisy Intermediate-Scale
Quantum (NISQ) devices, we design a special encoding method: a Continuous Relaxed Babai's Nearest Plane (CR-BNP) projection drives an adaptive mixed-radix encoder that greatly reduces both the
qubit count and the QUBO coefficient range, so that a single batched hardware submission suffices. We further derive a statistically bounded early-stopping threshold ($T_{\text{early}}$) that acts as a one-sided certificate and doubles as a Decision-LWE distinguisher. We validate the framework on the TU Darmstadt LWE Challenge, giving an end-to-end demonstration for both Search- and Decision-LWE of a $40$-dimensional instance on the Coherent Ising Machine CPQC-550. This work establishes a new
algorithm-hardware co-design paradigm for
quantum-classical hybrid cryptanalysis.
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Quantum Physics
Linear optical Bell state measurement for rotation-symmetric cat codes
Issa Oe, Suguru Endo and Rui Asaoka
Rotation-symmetric cat (RS-cat) codes are a bosonic-code platform for
quantum information processing, combining finite-energy realizability with robustness against
photon loss through their discrete rotational
symmetry. For applications in long-distance
quantum communication and fusion-based
quantum computation (FBQC), efficient Bell state measurement (BSM) is a key primitive. In this work, we consider a BSM protocol for RS-cat codes using only a half beam splitter (HBS) and
photon-number-resolving detectors (PNRDs). By exploiting the characteristic
photon-number structure induced by the discrete rotational
symmetry of RS-cat codes, our protocol extracts both
photon-number modulo and phase information for Bell-state discrimination. We show that, under ideal loss-free conditions, the proposed BSM protocol becomes deterministic for arbitrary
symmetry order $N$ for sufficiently large amplitudes $\alpha$. We further numerically evaluate the success probability under
photon loss and identify the loss regime in which higher-order RS-cat codes provide an advantage. Finally, we show that post-selection can enhance the success probability.
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Fluid Dynamics
A Conservative Time-Accurate Local Time-Stepping DG Scheme Based on a Weakly Compressible Model for Unsteady Low-Mach-Number Flows
Shihao Liu, Keli Zhang, Yuning Luan et al. (+1 more)
This paper presents a conservative high-order discontinuous Galerkin (DG) method featuring time-accurate local time stepping for simulating low-Mach-number unsteady flows, based on a weakly compressible formulation. In this model, pressure is defined solely as a function of density, eliminating the need for a global pressure Poisson equation typical of incompressible solvers while preserving the locality and conservation of compressible schemes. This makes it suitable for low-speed unsteady flows and aeroacoustics. The spatial discretization uses a strong-form nodal DG spectral element method (DGSEM) on Gauss-Lobatto-Legendre points. Inviscid fluxes are handled by numerical fluxes tailored to the weakly compressible system; specifically, a two-rarefaction approximate Riemann solver is developed for the constant-sound-speed barotropic equation of state. Viscous terms employ the incomplete interior penalty Galerkin (IIPG) method. For time integration, a continuous extension Runge-Kutta (CERK) scheme constructs
cell-local predictor
polynomials for continuous-in-time volume reconstructions. Face fluxes are split into interior and common contributions: the former matches the volume quadrature, while the latter uses piecewise Gaussian quadrature from continuous predictors. This split preserves discrete summation-by-parts cancellation and ensures conservative inter-element flux exchange.
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All authors Shihao Liu, Keli Zhang, Yuning Luan, Kai Liu
Solar and Stellar Astrophysics
Surface brightness-color relations for red giant branch stars: Observational constraints on metallicity effects using the ARD method
Jianping Xiong, Xiaodian Chen, Jiao Li et al. (+5 more)
Aims: We aim to quantify the
metallicity dependence of the SBCR for red
giant branch (RGB)
stars and to test the robustness of the relation using asteroseismic radii,
Gaia distances, and atmospheric parameters from APOGEE. Methods: We selected more than 2,000 RGB
stars from APOKASC-3 to calibrate and validate the SBCR. Johnson V magnitudes were synthesized from
Gaia XP spectra and homogenized to widely used SBCR photometric systems, while K_s photometry was taken from 2MASS. Angular diameters derived from asteroseismic radii and
Gaia distances (ARD) were used to construct the SBCR. We explored three fitting strategies:
metallicity-free,
metallicity-binned, and global
metallicity-dependent relations. Results: Over the range V-K_s=2-3, the SBCR shows only a weak
metallicity dependence. A change of 1 dex in [Fe/H] modifies the predicted angular diameter by less than 1%, well below the intrinsic scatter of the calibration (~0.05 mag). This result is consistent with theoretical expectations. Comparison with the interferometric sample reveals a systematic offset of ~1.5% toward smaller angular diameters in our SBCR predictions, with a mild color dependence. Conclusions: The
metallicity effect on the SBCR is small in the color range explored here, but it becomes relevant for sub-percent distance measurements. Our results show that large RGB samples with asteroseismic radii and
Gaia distances provide a powerful observational route for SBCR calibration, with clear potential for extension to cooler and redder
giants as the precision and parameter coverage of the input data improve.
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All authors Jianping Xiong, Xiaodian Chen, Jiao Li, Qiyuan Cheng, Xiaobin Zhang, Chao Liu, Zhanwen Han, Xuefei Chen
Strongly Correlated Electrons
Isometrization of Tensor Network States via Gauge Propagation
Zhiyu Jiang and Hiroshi Ueda
We introduce a gauge-propagation approach for approximately converting generic tensor-network states into an isometric tensor-network form with a prescribed orthogonality center. In one dimension, this propagation is exact because the non-isometric factor produced by a QR or singular-value decomposition is supported on a single virtual bond. In higher-dimensional networks, however, a local step can have several outgoing directions, and the residual factor is generally not separable into independent single-bond contributions. We address this local obstruction by approximating a local tensor, or a contracted local cluster, by structured terms consisting of an isometric factor multiplied by a tensor product of output-leg factors. The isometric factor is retained at the current site or cluster, while the output-leg factors are absorbed into neighboring tensors along the propagation directions. This construction applies to general local input-output partitions for which the input-side dimension is no smaller than the output-side dimension and provides a local truncation criterion for gauge propagation.
Benchmarks on random tensors show that the proposed decomposition is effective in the low-term regime and that the residual decreases for larger local clusters. For the loop-gas tensor representation of the Kitaev
spin liquid, two structured terms reduce the local residual to numerical precision, and the same cluster refinement further lowers the leading-term truncation error and reduces error accumulation during gauge propagation on a finite honeycomb network. These results identify a propagation-compatible local decomposition as a useful building block for approximate isometrization and as a potential initializer or preconditioner for variational isoTNS
algorithms.
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High Energy Physics (Experiment)
Ferromagnetic broadband sensing of axionlike dark matter
Chenhao Peng, Dmitry Budker, Yuanning Gao et al. (+6 more)
Levitated particles have demonstrated ultrahigh sensitivity to
magnetic fields and accelerations owing to their extremely low dissipation. Such systems have strong potential for fundamental physics research, particularly for the detection of
axions and axionlike particles, well-motivated dark matter candidates spanning a broad mass range. In this context, both high sensitivity and large bandwidth are essential. Here, we demonstrate a levitated magnet magnetometer based on an engineered double-resonance mode, achieving an effective linewidth at its optimal sensitivity that is approximately three orders of magnitude broader than those of previous approaches. Together with a hard-magnet array that enhances the
axion-induced signal and soft-
ferromagnetic shielding that suppresses environmental
magnetic noise, this system constitutes a hybrid
ferromagnetic platform for axionlike dark matter searches. We search for axionlike dark matter through its
photon coupling $g_{a\gamma}$ over the $40$-$3000\,\mathrm{Hz}$ frequency range and establish new direct limits in this frequency band. The best sensitivity is achieved near the upper resonance around $276\,\mathrm{Hz}$, where the magnetometer reaches a
magnetic-field resolution of $0.7\,\mathrm{fT}$, corresponding to a limit of $g_{a\gamma}\sim10^{-7}\,\mathrm{GeV}^{-1}$. At this frequency, this result improves upon previous direct limits by more than four orders of magnitude. The demonstrated high-bandwidth levitated sensor may also enable a broad range of applications, including biological sensing and precision measurements.
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All authors Chenhao Peng, Dmitry Budker, Yuanning Gao, Xinran Li, Jia Liu, Wei Ji, Jing Shu, Zhenxing Tang, Liheng Wang
High Energy Physics (Theory)
A Linearized Obstruction to the Supersymmetric Extension of Conformal Boundary Conditions in Euclidean Gravity
Xingyang Yu
The conformal boundary condition for
gravity fixes the boundary conformal class and the mean
curvature, leaving the trace-free extrinsic
curvature free as the conjugate response. It is the boundary-value form of York's conformal decomposition of gravitational data, shown to be well posed for Einstein metrics by Anderson. Witten identified it as the
elliptic replacement for the ill-posed Dirichlet condition in the finite-boundary perturbative Euclidean gravitational path integral. We show that this perturbative construction admits no half-supersymmetric extension in linearized minimal supergravity. For fixed conformal bosonic data, no half-dimensional gravitino boundary condition (local or pseudodifferential, APS-type included, with any compatible ghost condition at highest-derivative order) closes the full preserved
chiral supersymmetry. Supersymmetry first selects the natural local
chiral gravitino datum. Acting back on this datum then produces the trace-free extrinsic
curvature, precisely the response that the conformal prescription leaves unfixed. The obstruction is therefore not the failure of a particular
elliptic ansatz: even the
chiral/Robin completion that is LS-
elliptic and BRST-compatible at highest-derivative order would impose Dirichlet control on a Neumann response. The obstruction is pointwise in tangential momentum and survives compensating gauge transformations. It is a linearized, highest-derivative obstruction, not a global or nonlinear no-go; nonlinear supercovariant boundary terms may evade it by tying the trace-free extrinsic
curvature to gravitino bilinears.
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Exactly Solvable and Integrable Systems
Exact Harmonic Dimensional Reduction and Conformal Lifting for Multicomponent $(3+1)$ Nonlinear Schrödinger Systems
O.V. Kaptsov
A harmonic dimensional reduction framework is developed for $(3+1)\mathrm{D}$ systems of coupled nonlinear Schrödinger-type equations with stationary transverse trapping potentials. The central result is a lifting lemma: if the transverse phase functions are harmonic and the trapping potential exactly cancels the squared phase gradient, the full $(3+1)\mathrm{D}$ system reduces identically to a closed $(1+1)\mathrm{D}$ integrable hierarchy, and every solution of the reduced system lifts to an exact solution of the original multidimensional model. The framework is applied to four systems. For the scalar Gross–Pitaevskii equation, Kuznetsov–Ma breathers are embedded in $(3+1)\mathrm{D}$ geometries carrying
vortex lattices with finite, non-singular density at the cores. For the two-component Manakov system, the phase-inversion ansatz yields exact vector solutions with vanishing mass current and non-trivial transverse
spin current modulated by the longitudinal breather. For the three-component spinor $F=1$ Bose–Einstein condensate, a symmetric Kuznetsov–Ma breather and a
spin-exchange rogue wave are constructed, the latter exhibiting transient density amplification by a factor of nine in the $m_F=0$ channel. For the Maxwell–Bloch system, self-induced transparency
solitons, two-
soliton elastic collisions, and Kuznetsov–Ma breathers are lifted to full $(3+1)\mathrm{D}$ geometry, with population inversion remaining transversely uniform despite arbitrary phase winding in the cross-section.
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