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Ying Gu

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physics.optics astro-ph.HE Artificial Intelligence cond-mat.mes-hall cond-mat.soft cond-mat.stat-mech math.GT

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preprint2026arXiv

Towards Annotation-Free Validation of MLLMs: A Vision-Language Logical Consistency Metric

Dominant accuracy evaluation might reward unwarranted guessing of Large Language Models, and it might not be applicable to novel tasks for model validation without ground-truth (gt) annotation. Based on basic logic principle, we propose a novel framework to evaluate the vision-language logical consistency of MLLMs on both sufficient and necessary cause-effect relations. We define Vision-Language Logical Consistency Metric (VL-LCM) on traditional MC-VQA tests, and recent NaturalBench tests without the need for gt annotation. Through systematic experiments on representative VL benchmark MMMU and recent VL challenges like NaturalBench, we evaluated 11 recent open-source MLLMs from 4 frontier families. Our findings reveal that, despite significant progress of recent MLLMs on accuracy, logical consistency lags behind significantly. Extensive evaluations on the correlations of VL-LCM with metrics on gt, the reliability of LCM, and the relation of VL-LCM with response distribution justify the validity and applicability of VL-LCM even without gt annotation. Our findings suggest that, beyond accuracy, logical consistency could be employed for both accuracy and reliability. VL-LCM can also be employed for MLLM selection, validation, and reliable answer justification in novel tasks without gt annotation.

preprint2024arXiv

Lobe-dominated gamma-ray Emission of Compact Symmetric Objects

The $γ$ -ray emitting compact symmetric objects (CSOs) PKS 1718--649, NGC 3894, and TXS 0128+554 are lobe-dominated in the radio emission. In order to investigate their $γ$ -ray radiation properties, we analyze the $\sim$ 14-yr Fermi/LAT observation data of the three CSOs. They all show the low luminosity ( $10^{41}-10^{43}$ erg s $^{-1}$ ) and no significant variability in the $γ$ -ray band. Their $γ$ -ray average spectra can be well fitted by a power-law function. These properties of $γ$ -rays are clearly different from the $γ$ -ray emitting CSOs CTD 135 and PKS 1413+135, for which the $γ$ -rays are produced by a restarted aligned jet. In the $L_γ-Γ_γ$ plane, the three CSOs are also located at the region occupied by radio galaxies (RGs) while CTD 135 and PKS 1413+135 display the similar feature to blazars. Together with the similar radio emission property to $γ$ -ray emitting RGs Cen A and Fornax A, we speculate that the $γ$ -rays of the three CSOs stem from their extended mini-lobes. The broadband spectral energy distributions of the three CSOs can be well explained by the two-zone leptonic model, where their $γ$ -rays are produced by the inverse Compton process of the relativistic electrons in extended region. By extrapolating the observed Fermi/LAT spectra to the very high energy band, we find that TXS 0128+554 among the three CSOs may be detected by the Cherenkov Telescope Array in future.

preprint2022arXiv

Gain-gain and gain-lossless PT-symmetry broken from PT-phase diagram

Parity-time (PT) symmetry and broken in micro/nano photonic structures have been investigated extensively as they bring new opportunities to control the flow of light based on non-Hermitian optics. Previous studies have focused on the situations of PT-symmetry broken in loss-loss or gain-loss coupling systems. Here, we theoretically predict the gain-gain and gain-lossless PT-broken from phase diagram, where the boundaries between PT-symmetry and PT-broken can be clearly defined in the full-parameter space including gain, lossless and loss. For specific micro/nano photonic structures, such as coupled waveguides, we give the transmission matrices of each phase space, which can be used for beam splitting. Taking coupled waveguides as an example, we obtain periodic energy exchange in PT-symmetry phase and exponential gain or loss in PT-broken phase, which are consistent with the phase diagram. The scenario giving a full view of PT-symmetry or broken, will not only deepen the understanding of fundamental physics, but also will promote the breakthrough of photonic applications like optical routers and beam splitters.

preprint2022arXiv

Geometric intersections of loops on surfaces

Based on Nielsen fixed point theory and Gröbner-Shirshov basis, we obtain a simple method to compute geometric intersection numbers and self-intersection geometric numbers of loops on surfaces.

preprint2022arXiv

GeV $γ$ -ray Emission of Compact Steep-Spectrum Source 4C +39.23B

Thirteen yr observation data of 4FGL J0824.9+3915 with the Large Area Telescope on board the Fermi Gamma Ray Space Telescope (Fermi/LAT) are analyzed for revisiting whether 4C +39.23B, a compact steep-spectrum (CSS) source closed to a flat-spectrum radio quasar (FSRQ) 4C +39.23A in the $γ$ -ray emitting region of 4FGL J0824.9+3915, is a $γ$ -ray emitter. We find that the time-integrated $γ$ -ray emission of 4FGL J0824.9+3915 is overwhelmingly dominated by 4C +39.23A. It shows significant variability at a 6.7 $σ$ confidence level and the average $γ$ -ray flux in the 0.1--300 GeV energy band is $(1.60\pm 0.15)\times10^{-8}$ ph cm $^{-2}$ s $^{-1}$ with a power-law photon spectral index of $2.48\pm0.05$ . During MJD 57500--58500, 4FGL J0824.9+3915 is in a low state with a steady $γ$ -ray flux. Analyzed the Fermi/LAT observation data in this time interval, it is found that the TS values of the $γ$ -ray emission from 4C +39.23A and 4C +39.23B are $\sim5$ and $\sim 31$ , respectively, indicating that the $γ$ -ray emission in this time interval is dominated by the CSS 4C +39.23B. The derived average flux in this time interval for 4C +39.23B is $(9.40\pm4.10)\times 10^{-9}$ ph cm $^{-2}$ s $^{-1}$ with $Γ_γ=2.45\pm0.17$ . Attributing the spectral energy distribution (SED) of 4C +39.23B to the radiations from its core and extended region, we show that the SED can be represented with a two-zone leptonic model. Its $γ$ -ray emission is contributed by the core region. The derived magnetic field strength and Doppler boosting factor of the core are 0.13 G and 6.5. Comparing 4C +39.23B with other $γ$ -emitting CSSs and compact symmetric objects (CSOs) in the $Γ_γ-L_γ$ plane, it resembles CSSs.

preprint2021arXiv

Local phase delay effect on the asymmetric spectroscopy of plasmon-exciton coupling systems

The phase delay of a local electric field, being well-known in plasmonic nanostructures, has seldom been investigated to modulate the plasmon-exciton interaction. Here, with the single-particle spectroscopy method, we experimentally investigate the phase effect in plasmon-exciton coupling systems consisting of monolayer WSe2 and an individual gold nanorod. The local plasmon phase delay is tuned by adopting various nanorods with different resonant energies respective to the exciton. We find that the local plasmon phase delay between the excitons and the plasmonic modes is as equally essential as the amplitude. The phase delay modulates the plasmon-exciton coupling considerably, resulting in an asymmetric spectral line-shape due to the interference behavior. There is an excellent agreement for the phase delay between the numerically calculated near-field phase distribution and the experimental results. The local phase delay can act as an effective way to modulate the properties of plexcitonic coupling at the nanoscale, which may have potential applications in nanoscale sensing, solar energy devices, and enhancing nonlinear processes.

preprint2019arXiv

Topologically Enabled Ultralarge Purcell Enhancement Robust to Photon Scattering

Micro/nanoscale single photon source is a building block of on-chip quantum information devices. Owing to possessing ultrasmall optical mode volume, plasmon structures can provide large Purcell enhancement, however scattering and absorption are two barriers to prevent them from being used in practice. To overcome these barriers, we propose the topological photonic structure containing resonant plasmon nanoantenna, where nanoantenna provides large Purcell enhancement while topological photonic crystal guides all scattering light into its edge state. Through the optical mode design, the rate of single photons emitted into the edge state reaches more than 104γ0 simultaneously accompanied with an obvious reduction of absorption. This kind of nonscattering large Purcell enhancement will provide new sight for on-chip quantum light sources such as a single photon source and nanolaser.

preprint2002arXiv

Fluctuations and scaling of inverse participation ratios in random binary resonant composites

We study the statistics of local field distribution solved by the Green's-function formalism (GFF) [Y. Gu et al., Phys. Rev. B {\bf 59} 12847 (1999)] in the disordered binary resonant composites. For a percolating network, the inverse participation ratios (IPR) with $q=2$ are illustrated, as well as the typical local field distributions of localized and extended states. Numerical calculations indicate that for a definite fraction $p$ the distribution function of IPR $P_q$ has a scale invariant form. It is also shown the scaling behavior of the ensemble averaged $<P_{q}>$ described by the fractal dimension $D_q$ . To relate the eigenvectors correlations to resonance level statistics, the axial symmetry between $D_2$ and the spectral compressibility $χ$ is obtained.

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Ying Gu

Research overview

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8 publications

Towards Annotation-Free Validation of MLLMs: A Vision-Language Logical Consistency Metric

Lobe-dominated gamma-ray Emission of Compact Symmetric Objects

Gain-gain and gain-lossless PT-symmetry broken from PT-phase diagram

Geometric intersections of loops on surfaces

GeV $γ$ -ray Emission of Compact Steep-Spectrum Source 4C +39.23B

Local phase delay effect on the asymmetric spectroscopy of plasmon-exciton coupling systems

Topologically Enabled Ultralarge Purcell Enhancement Robust to Photon Scattering

Fluctuations and scaling of inverse participation ratios in random binary resonant composites

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Building this map preview

Ying Gu

Research overview

Is this your work?

8 publications

Towards Annotation-Free Validation of MLLMs: A Vision-Language Logical Consistency Metric

Lobe-dominated gamma-ray Emission of Compact Symmetric Objects

Gain-gain and gain-lossless PT-symmetry broken from PT-phase diagram

Geometric intersections of loops on surfaces

GeV γγγ-ray Emission of Compact Steep-Spectrum Source 4C +39.23B

Local phase delay effect on the asymmetric spectroscopy of plasmon-exciton coupling systems

Topologically Enabled Ultralarge Purcell Enhancement Robust to Photon Scattering

Fluctuations and scaling of inverse participation ratios in random binary resonant composites

See the researcher in context

Building this map preview

GeV $γ$ -ray Emission of Compact Steep-Spectrum Source 4C +39.23B