arXiv subjects

Yudong Cui

Publications and source records attributed to Yudong Cui.

At least 19 recordsLinked to original sources

arXiv2026

Time-dependent multi-energy neutrino emission from symbiotic recurrent novae: the role of accretion disks

Symbiotic recurrent novae provide a unique laboratory for studying thermonuclear explosions, shock evolution, and nonthermal particle acceleration in dense circumstellar environments. In this work, we develop a time-dependent, multi-energy framework to describe neutrino emission from such systems, consistently incorporating both MeV neutrinos produced during thermonuclear runaway and GeV neutrinos generated through hadronic interactions in nova-driven shocks. Using RS Oph as a benchmark source, we model the evolution of the shock interacting with both the red giant wind and a dense accretion disk surrounding the white dwarf. We show that the resulting neutrino signal exhibits a characteristic two-component temporal structure: an early, rapidly rising MeV component tracing nuclear burning, followed by a delayed GeV component governed by shock propagation and particle acceleration. The presence of an accretion disk can significantly enhance the early-time GeV neutrino emission by providing a dense target for proton-proton interactions. This leads to a pronounced neutrino flux within the first few hours after eruption, a feature absent in wind-dominated scenarios. We further evaluate the detectability of these signals and find that while the MeV component remains below current detection thresholds, the GeV neutrino emission from nearby systems may become accessible to next-generation detectors. Our results highlight the critical role of the circumstellar structure in shaping nova neutrino emission and demonstrate that symbiotic recurrent novae are promising targets for future multi-messenger observations.

astro-ph.HE↗

arXiv2026

Risk assessment of muon single-event effects for low-altitude aircraft

With the rapid development of low-altitude economy, the radiation environment safety of low-altitude aircraft such as drones and electric vertical take-off and landing aircraft has attracted increasing attention. Although the dense lower atmosphere traditionally serves as an effective shield against cosmic radiation, the shrinking feature sizes of modern integrated circuits greatly enhance their vulnerability to single-event effects (SEEs). This study quantitatively evaluates muon-induced SEE risks for low-altitude aircraft in various regions of China under both static cosmic-ray background and ground-level enhancement (GLE) events, aiming to provide critical guidance for the next-generation low-altitude aviation platforms.Using city-specific atmospheric models within the CORSIKA framework, we simulate atmospheric shower processes and obtain reliable energy spectra for low-energy muons (10-100 MeV). We also employ simulation data from other research groups to estimate muon-induced SEE cross sections for transistors at different process nodes, including bulk, FD-SOI, and FinFET technologies. By incorporating solar energetic particle spectra associated with GLE events, we assess muon-induced SEE risks under both static and GLE conditions. Our results show that under static conditions, flight control systems with 1 MB memory using advanced nodes below 45 nm and bulk transistors face non-negligible muon-induced SEE risks in all Chinese cities. In contrast, systems with FD-SOI transistors can effectively mitigate these risks. For large-memory systems (1 GB), redundancy or other hardening measures are essential regardless of the process technology. Regarding GLE events, we introduce the concept of muon hazard levels to evaluate regional risk variations. During GLEs, the increase in muon-induced SEE risk is negligible in mid-to-low latitude regions but becomes significant at high latitudes.

astro-ph.IM↗

arXiv2026

LHAASO J1849$-$0002: A Hybrid Lepto-Hadronic Interpretation of PeV Gamma-Ray Emission

Recently, LHAASO detected gamma-ray emission from the pulsar wind nebula (PWN) J1849-0001 extending up to approximately 2 PeV, providing strong evidence for PeV particle acceleration. To explain the origin of this ultra-high-energy emission, we investigate three physical scenarios: a pure leptonic model, a hadronic-dominated model, and a hybrid lepto-hadronic model. We show that while both pure leptonic and hadronic-dominated models can reproduce parts of the multiwavelength spectral energy distribution (SED), neither can simultaneously explain the entire dataset, particularly the PeV tail. The leptonic scenario requires an unrealistically high electron cutoff energy, while the hadronic model underpredicts the highest-energy emission. We therefore propose a hybrid model that combines inverse Compton emission from PWN electrons with hadronic interactions between escaped cosmic rays and a nearby molecular cloud. In this framework, a suppressed diffusion coefficient ($\sim 1\%$ of the Galactic average) is required to confine PeV particles in the source vicinity. This model successfully reproduces the full SED, including the approximately 2 PeV emission. We further calculate the associated neutrino flux, and show the sensitivity of NEON to this source. Our results support the interpretation that evolved PWNe embedded in complex environments can act as Galactic PeVatrons.

astro-ph.HE↗

arXiv2026

Bound states of solitons in fiber lasers

This article presents a systematic review of theoretical and experimental findings for bound states of two and several dissipative solitons in fiber lasers. The theoretical basis underlying the formation and stabilization of soliton molecules in the fibers, which is provided by the complex Ginzburg-Landau equations and bound states of such equations, is presented in necessary detail, which is followed by a detailed presentation of experimental findings, including very recent ones. In particular, included are the results for the multi-soliton bound states in the fibers, as well as for the bound states in the temporal and frequency domains, single-component (scalar) and two-component (vector), two- and multi-soliton modes, as well as for bound states of spatiotemporal dissipative solitons in the lasers based on multimode fibers.

physics.optics↗

arXiv2026

Deciphering the IceCube Diffuse Neutrino Observations via AGN Variability

The physical origin of the diffuse neutrino background and its spectral break at $\sim$ 30 TeV remain a major puzzle in multi-messenger astrophysics. In this work, we demonstrate that this spectral feature is a natural consequence of AGN activity cycles and the resulting cosmic ray (CR) propagation. We present a unified model coupling the active and quiescent phases of AGNs, where CRs accelerated in the active core undergo subsequent diffusion and hadronic interactions in the host galaxy during the quiescent phase. The superposition of these distinct evolutionary phases yields dual spectral breaks, particularly the one at tens of TeV. Under realistic energetics, our model simultaneously accounts for the IceCube diffuse flux and fits the neutrino emissions of diverse sources, ranging from the blazar TXS 0506+056 to the Seyfert galaxies NGC 7469, CGCG 420-015, and the Circinus Galaxy. Our findings reveal that temporal variability is essential for deciphering the cosmic neutrino landscape and tracking high-energy CR escape.

astro-ph.HE↗

arXiv2026

Quantum tunnelling-integrated optoplasmonic nanotrap enables conductance visualisation of individual proteins

Biological electron transfer (ET) relies on quantum mechanical tunnelling through a dynamically folded protein. Yet, the spatiotemporal coupling between structural fluctuations and electron flux remains poorly understood, largely due to limitations in existing experimental techniques, such as ensemble averaging and non-physiological operating conditions. Here, we introduce a quantum tunnelling-integrated optoplasmonic nanotrap (QTOP-trap), an optoelectronic platform that combines plasmonic optical trapping with real-time quantum tunnelling measurements. This label-free approach enables single-molecule resolution of protein conductance in physiological electrolytes, achieving sub-3 nm spatial precision and 10-μs temporal resolution. By synchronising optoelectronic measurements, QTOP-trap resolves protein-specific conductance signatures and directly correlates tertiary structure dynamics with conductance using a "protein switch" strategy. This methodology establishes a universal framework for dissecting non-equilibrium ET mechanisms in individual conformational-active proteins, with broad implications for bioenergetics research and biomimetic quantum device design.

physics.bio-ph↗

arXiv2025

A proposed deep sea Neutrino Observatory in the Nanhai

Over the past ten years, several breakthroughs have been made in multi-messenger astronomy. Thanks to the IceCube Neutrino Observatory, the detection of astrophysical neutrinos was proved to be practical. However, due to the limited statistics and field of view, only a few sources have been associated with IceCube neutrinos, making new and larger neutrino telescopes necessary. We propose the NEutrino Observatory in the Nanhai (NEON), located in the South China Sea to be complementary for the global neutrino detectors. This proposal describes the design and layout of the array and reports on comprehensive simulations conducted to assess its performance. The NEON project, with a volume of 10 km$^3$, achieves an angular resolution of 0.1$^\circ$ at 100 TeV. With 10 years of operation, the project's 5$σ$ sensitivity is estimated as $E^2Φ\sim 2 \times 10^{-10}$ GeV cm$^{-2}$ s$^{-1}$ for a source spectrum index of -2. We found that the variation in depth from 1700 to 3500 meters does not significantly influence the sensitivity to steady sources.

astro-ph.HE↗

arXiv2025

The traveling-PWN modeling attempt on the enigmatic LHAASO dumbbell-like structure

The first LHAASO catalog presents six enigmatic ultra-high-energy (UHE) gamma-ray sources with lonely > 25 TeV emission being detected, which are indicated as 1LHAASO: J0007+5659u, J0206+4302u, J0212+4254u, J0216+4237u, J1740+0948u, and J1959+1129u. No counterparts of the six sources have been observed, except two energetic pulsars, PSR J0218+4232 and PSR J1740+1000. Among them, 1LHAASO: J0206+4302u, J0212+4254u, and J0216+4237u are connected on the significance map and constituted a dumbbell-like structure. They are close in position and show a similar spectral shape, suggesting a physical association among them. To explain the origin of the six LHAASO sources, especially the intriguing dumbbell-like structure, we conducted the leptonic and hadronic modeling research according to our multiwavelength and multimessenger study. For the dumbbell-like structure, models with traveling-PWNe were considered. The multiwavelength and multimessenger study was based on the Fermi-LAT, Swift-XRT, Planck, CfA 12CO survey, and IceCube neutrino datasets. In the traveling-PWN modeling research, we assumed an isotropic and homogeneous diffusion condition and discussed the influence of diffusion coefficient, distance, and proper motion velocity. No counterparts are discovered in our multiwavelength and multimessenger study, except the two known pulsars. The traveling-PWN modeling attempt with a single PWN appears implausible to explain the dumbbell-like structure, as the diffusion coefficient needs to be much lower than the Bohm limit. A double traveling-PWNe model is also explored and can account for the results of LHAASO-KM2A observation. However, the probability of occurrence of this explanation is significantly lower than that of a conventional triple PWNe explanation.

astro-ph.HE↗

arXiv2025

SNR G54.1+0.3, a PeVatron candidate unveiled by LHAASO

Recently, the LHAASO Collaboration reported the first very-high-energy gamma-ray catalog, containing 90 TeV sources. Among these sources, 1LHAASO J1929+1846u is located 0.3$^\circ$ west of SNR G54.1+0.3 and also lies within a $+53 \, \text{km s}^{-1}$ cloud (the Western Cloud). Moreover, one of the IceCube track-type high-energy starting events is found around 1.3$^\circ$ north of 1LHAASO J1929+1846u, which may serve as strong evidence for the hadronic origin of this TeV source. SNR G54.1+0.3 is a young supernova remnant (SNR), with a powerful pulsar wind nebula (PWN) inside. Its X-ray radiation from the PWN and the SNR Shell can be clearly identified. The radio emission from the PWN region is also given. However, given the angular resolution of gamma-ray experiments, the entire SNR region is viewed as a point source by Fermi-LAT, H.E.S.S. and VERITAS. In this work, we explore a hybrid scenario where SNR G54.1+0.3 is indeed associated with the Western Cloud, and we derive the multi-wavelength emissions from the PWN, the SNR Shell, and the Western Cloud, separately. Our model can explain the observations well, indicating that SNR G54.1+0.3 might be an excellent candidate of Galactic PeVatron and neutrino source.

astro-ph.HE↗

arXiv2024

SNR G54.1+0.3, a PeVatron candidate unveiled by LHAASO

Recently, the LHAASO Collaboration presented the first very-high-energy gamma-ray catalog, containing 90 TeV sources. Among these sources, 1LHAASO J1929 +1846u* is located 0.3$^\circ$ west of SNR G54.1 +0.3 and it also lies inside a $+53 \, \text{km s}^{-1}$ cloud (the Western Cloud) which may be associate with SNR G54.1+0.3. Moreover, one of IceCube's HESE track events is found at 1.3$^\circ$ north of 1LHAASO J1929 +1846u*. SNR G54.1+0.3 is young, with a powerful PWN inside. The X-ray radiation from the regions of SNR shell and PWN can be distinguished clearly. The radio emission from the PWN region is also available. However, due to the low angular resolution, the gamma-ray emission at the SNR by Fermi, HESS and VERITAS are considered as point sources. In this work, we explore a scenario that SNR G54.1 +0.3 is indeed associated with the Western Cloud and we derive the emissions from the PWN, the SNR shell, and the nearby molecular cloud. Our results can explain the multi-messenger observations, indicating that 1LHAASO J1929 +1846u* might be the excellent candidate of Galactic PeVatron.

astro-ph.HE↗

arXiv2022

Is Fermi 1544-0649 a misaligned blazar? discovering the jet structure with VLBI

Fermi J1544-0649 is a transient GeV source first detected during its GeV flares in 2017. Multi-wavelength observations during the flaring time demonstrate variability and spectral energy distribution(SED) that are typical of a blazar. Other than the flare time, Fermi J1544-0649 is quiet in the GeV band and looks rather like a quiet galaxy (2MASX J15441967-0649156) for a decade. Together with the broad absorption lines feature we further explore the "misaligned blazar scenario". We analyzed the Very Long Baseline Array (VLBA) and East Asian VLBI Network (EAVN) data from 2018 to 2020 and discovered the four jet components from Fermi J1544-0649. We found a viewing angle around 3.7° to 7.4°. The lower limit of the viewing angle indicates a blazar with an extremely low duty cycle of the gamma-ray emission, the upper limit of it supports the "misaligned blazar scenario". Follow-up multi-wavelength observations after 2018 show Fermi J1544-0649 remains quiet in GeV, X-ray, and optical bands. Multi-messenger search of neutrinos is also performed, and an excess of 3.1 σ significance is found for this source.

astro-ph.HE↗

arXiv2022

On-demand harnessing of photonic soliton molecules

Soliton molecules (SMs) are fundamentally important modes in nonlinear optical systems. It is a challenge to experimentally produce SMs with a required temporal separation in mode-locked fiber lasers. Here, we propose and realize an experimental scenario for harnessing SM dynamics in a laser setup. In particular, we tailor SMs in a mode-locked laser controlled by second-order group-velocity dispersion and dispersion losses: the real part of dispersion maintains the balance between the dispersion and nonlinearity, while the dispersion loss determines the balance of gain and losses. The experimental results demonstrate that the dispersion loss makes it possible to select desired values of the temporal separation (TS) in bound pairs of SMs in the system. Tunability of the SM's central wavelength and the corresponding hysteresis are addressed too. The demonstrated regime allows us to create multiple SMs with preselected values of the TS and central wavelength, which shows the potential of our setup for the design of optical data-processing schemes.

physics.optics↗

arXiv2022

Spatially decomposed $γ$-ray features surrounding SNR Kes 79 & PSR J1853+0056

There have been substantial improvements on Fermi Large Area Telescope (LAT) data and analysis tools since the last analysis on the mid-aged supernova remnant (SNR) Kes 79 (Auchettl et al. 2014). Recent multi-wavelength studies confirmed its interaction with molecular clouds. About $0.36\degr$ north from Kes 79, a powerful pulsar -- PSR J1853+0056 also deserves our attention. In this work, we analyse the 11.5-year Fermi-LAT data to investigate the $γ$-ray feature in/around this complex region. Our result shows a more significant detection ($\sim$34.8$σ$ in 0.1--50 GeV) for this region. With $\ge$5 GeV data, we detect two extended sources -- Src-N (the brighter one; radius $\approx0.31\degr$) concentrated at the north of the SNR while enclosing PSR J1853+0056, and Src-S (radius $\approx0.58\degr$) concentrated at the south of the SNR. Their spectra have distinct peak energies ($\sim$1.0 GeV for Src-N and $\lesssim$0.5 GeV for Src-S), suggesting different origins for them. In our hadronic model that includes the leaked cosmic-rays (CRs) from the shock-cloud collision, even with extreme values of parameters, SNR Kes 79 can by no means provide enough CRs reaching clouds at Src-N to explain the local GeV spectrum. We propose that the Src-N emission could be predominantly reproduced by a putative pulsar wind nebula (PWN) powered by PSR J1853+0056. On the other hand, our same hadronic model can reproduce a majority of the GeV emission at Src-S with typical values of parameters, while the three known pulsars inside Src-S release a total power that is too low to account for half of its $γ$-ray emission.

astro-ph.HE↗

arXiv2020

A multi-wavelength study of the gamma-ray binary candidate HESS J1832-093

We investigate the nature of the unidentified very-high-energy (VHE) gamma-ray object, HESS J1832-093, in a multi-wavelength context. Based on X-ray variability and spectral index ($Γ_X\sim\,1.5$), and its broad-band spectrum (which was remarkably similar to HESS J0632+057, a confirmed gamma-ray binary), HESS J1832-093 has been considered to be a strong gamma-ray binary candidate in previous works. In this work, we provide further evidence for this scenario. We obtained a spectrum of its IR counterpart using Gemini/Flamingo, finding absorption lines that are usually seen in massive stars, in particular O stars. We also obtained a rather steep ATCA spectrum ($α=-1.18^{+1.04}_{-0.88}$) which prefers a gamma-ray binary over an AGN scenario. Based on spatial-spectral analysis and variability search, we found that 4FGL J1832.9-0913 is possible to be associated with SNR G22.7-0.2 rather than with HESS J1832-093 only.

astro-ph.HE↗

arXiv2019

XPM-forced frequency-oscillating soliton in mode-locked fiber laser

Cross phase modulation (XPM) could induce soliton trapping in nonlinear medium, which has been employed to achieve vector soliton, optical switching and optical analog of gravity-like potentials. These results are generally within the definition in Hamilton system. Here, we report on the observation of a XPM-forced frequency-oscillating soliton (XFOS) whose wavelength exhibits redshift and blueshift periodically like dancing in a mode-locked fiber laser under moderate birefringence. XFOS consists of two orthogonally polarized components exhibiting simultaneous frequency oscillation driven by XPM and gain effect, which allows withstanding higher pulse energy. The pulse trapping is maintained by differentiating the frequency-shift rate. Numerical simulations agree very well with experimental results, revealing an idiosyncratic evolution dynamic for asymmetry pulses in nonlinear dissipative system and envisaging a technique to control pulse feature with preset pulse chirp. XFOS may exist generally in polarization-independent ultrafast lasers, which enriches soliton family and brings useful insights into nonlinear science and applications.

physics.optics↗

arXiv2019

Is the SNR HESS J1731-347 colliding with molecular clouds?

The supernova remnant (SNR) HESS J1731-347 is a young SNR which displays a non-thermal X-ray and TeV shell structure. A molecular cloud at a distance of 3.2 kpc is spatially coincident with the western part of the SNR, and it is likely hit by the SNR. The X-ray emission from this part of the shell is much lower than from the rest of the SNR. Moreover, a compact GeV emission region coincident with the cloud has been detected with a soft spectrum. These observations seem to imply a shock-cloud collision scenario at this area, where the stalled shock can no longer accelerate super-TeV electrons or maintain strong magnetic turbulence downstream, while the GeV cosmic rays (CRs) are released through this stalled shock. To test this hypothesis, we have performed a detailed Fermi-LAT reanalysis of the HESS J1731-347 region with over 9 years of data. We find that the compact GeV emission region displays a spectral power-law index of -2.4, whereas the GeV emission from the rest of the SNR (excluding the cloud region) has an index of -1.8. A hadronic model involving a shock-cloud collision scenario is built to explain the -ray emission from this area. It consists of three CR sources: run-away super-TeV CRs that have escaped from the fast shock, leaked GeV CRs from the stalled shock, and the local CR sea. The X-ray and -ray emission of the SNR excluding the shock-cloud interaction region is explained in a one-zone leptonic model. Our shock-cloud collision model explains well the GeV-TeV observations from both cloud regions around HESS J1731-347, i.e. from the cloud in contact with the SNR and from the more distant cloud which is coincident with the nearby TeV source HESS J1729-345. We find however that the leaked GeV CRs from the shock-cloud collision do not necessarily dominate the GeV emission from the clouds, due to a comparable contribution from the local CR sea.

astro-ph.HE↗

arXiv2019

X-Ray spectral evolution of PSR~J2032+4127 during the 2017 periastron passage

We report X-ray data analysis results obtained from Chandra, XMM-Newton, NuSTAR and Swift observations of PSR J2032+4127 taken before, during, and after the periastron on 2017 November 13. We found the first clear evidence of a change in the X-ray spectral index over the passage period, thanks to a broad and sensitive spectral coverage by XMM-Newton and NuSTAR. We analysed the joint XMM-Newton and NuSTAR observation epochs with power-law and broken power-law model. We have obtained change in spectral parameters before and after the periastron passage for both models. The spectra get softened after the passage. The evolution of the spectral index and break energy before and after the periastron may indicate a change in the physical state of shock-accelerated electrons.

astro-ph.HE↗

arXiv2018

Observation of the evolution dynamics from starting to shutting of SWNT-mode-locked fiber laser

Dispersive Fourier transform (TS-DFT) technique opens a fascinating pathway to explore the ultrafast non-repetitive even, which has been employed to study the build-up process of mode-locked lasers. Here the whole evolution dynamics (from starting up to shutting down) of conventional soliton (CS), stretched pulse (SP) and dissipative soliton (DS) are investigated by using TS-DFT technique. The relaxation oscillation can be always observed before the formation of stable pulse operation, which is stemmed from the inherent advantage of the single-walled carbon nanotube. However, owing to the different pulse features, they exhibit the distinct evolution dynamics in the starting and shutting processes. Some critical phenomena are observed, including transient complex spectrum broadening and frequency-shift interaction of SP and picosecond pulses. These results could further deepen the understanding of the mode-locked fiber laser from the real-time point of view and is helpful for the laser design and applications.

physics.optics↗