Graduate University for Advanced Studies
It is very much intriguing if the Planck scale MPlM_{\rm{Pl}} is not a fundamental parameter. The Brans-Dicke gravity is nothing but the theory where the Planck scale MPlM_{\rm{Pl}} is indeed an illusional parameter. The theory predicts a massless scalar boson whose exchanges between matters induce unwanted long range forces. We solve this problem imposing there is no dimensionful parameter in the theory, even at the quantum level. We further extend the theory by including a R2R^2 term and a non-minimal coupling of the Standard Model Higgs to gravity, as their coefficients are dimensionless. This extension provides a heavy inflaton field that is consistent with all cosmological observations, with a potential very similar to that of the Starobinsky model. The inflaton necessarily decays into the massless scalar bosons, resulting in a non-negligible amount of dark radiation in the present universe. We demonstrate that the inflation model yields a sufficiently high reheating temperature for successful leptogenesis, and we also discuss a possible candidate for dark matter.
We study heavy-hadron semileptonic decays proceeding via bcb \to c transition, such as BD()τνˉτB \to D^{(*)}\tau\bar{\nu}_\tau and ΛbΛcτνˉτ\Lambda_b \to \Lambda_c\tau\bar{\nu}_\tau. In the heavy-quark limit, where the heavy-quark symmetry holds, we construct a general heavy-quark sum rule for these decays based on the spin decomposition picture. The relation holds directly for the squared amplitudes without requiring phase-space integration. We then apply this relation to reproduce the sum rule among BD()τνˉτB \to D^{(*)}\tau\bar{\nu}_\tau and ΛbΛcτνˉτ\Lambda_b \to \Lambda_c\tau\bar{\nu}_\tau. Furthermore, we extend the analysis to ΩbΩc()\Omega_b \to \Omega_c^{(*)} transitions and those involving excited states, such as B{D0,D1}B \to \{D_0^*,D_1^*\} and B{D1,D2}B \to \{D_1,D_2^*\}.
We examine various perspectives on the decay of correlation for the uniform distribution over proper qq-edge colorings of graphs with maximum degree Δ\Delta. First, we establish the coupling independence property when q3Δq\ge 3\Delta for general graphs. Together with the work of Chen et al. (2024), this result implies a fully polynomial-time approximation scheme (FPTAS) for counting the number of proper qq-edge colorings. Next, we prove the strong spatial mixing property on trees, provided that $q> (3+o(1))\Delta$. The strong spatial mixing property is derived from the spectral independence property of a version of the weighted edge coloring distribution, which is established using the matrix trickle-down method developed in Abdolazimi, Liu and Oveis Gharan (FOCS, 2021) and Wang, Zhang and Zhang (STOC, 2024). Finally, we show that the weak spatial mixing property holds on trees with maximum degree Δ\Delta if and only if q2Δ1q\ge 2\Delta-1.
Inverse imaging problems are inherently under-determined, and hence it is important to employ appropriate image priors for regularization. One recent popular prior---the graph Laplacian regularizer---assumes that the target pixel patch is smooth with respect to an appropriately chosen graph. However, the mechanisms and implications of imposing the graph Laplacian regularizer on the original inverse problem are not well understood. To address this problem, in this paper we interpret neighborhood graphs of pixel patches as discrete counterparts of Riemannian manifolds and perform analysis in the continuous domain, providing insights into several fundamental aspects of graph Laplacian regularization for image denoising. Specifically, we first show the convergence of the graph Laplacian regularizer to a continuous-domain functional, integrating a norm measured in a locally adaptive metric space. Focusing on image denoising, we derive an optimal metric space assuming non-local self-similarity of pixel patches, leading to an optimal graph Laplacian regularizer for denoising in the discrete domain. We then interpret graph Laplacian regularization as an anisotropic diffusion scheme to explain its behavior during iterations, e.g., its tendency to promote piecewise smooth signals under certain settings. To verify our analysis, an iterative image denoising algorithm is developed. Experimental results show that our algorithm performs competitively with state-of-the-art denoising methods such as BM3D for natural images, and outperforms them significantly for piecewise smooth images.
This paper explores the efficacy of self-supervised pre-trained Vision Transformers (ViTs) for deepfake detection, comparing them against traditional ConvNets and supervised ViTs. The research demonstrates that partially fine-tuned self-supervised ViTs, particularly DINOv2, achieve state-of-the-art performance on both seen and unseen deepfakes, with DINOv2 reaching an EER of 5.63% on seen data and 27.61% on unseen diffusion fakes, while also providing natural explainability through attention maps.
To understand orbital-angular-momentum contributions is becoming crucial for clarifying nucleon-spin issue in the parton level. Twist-two structure functions b_1 and b_2 for spin-one hadrons could probe orbital-angular-momentum effects, which reflect a different aspect from current studies for the spin-1/2 nucleon, since they should vanish if internal constituents are in the S state. These structure functions are related to tensor structure in spin-one hadrons. Studies of such tensor structure will open a new field of high-energy spin physics. The structure functions b_1 and b_2 are described by tensor-polarized quark and antiquark distributions delta_T-q and delta_T-qbar. Using HERMES data on the b_1 structure function for the deuteron, we made an analysis of extracting the distributions delta_T-q and delta_T-qbar in a simple x-dependent functional form. Optimum distributions are proposed for the tensor-polarized valence and antiquark distribution functions from the analysis. A finite tensor polarization is obtained for antiquarks if we impose a constraint that the first moments of tensor-polarized valence-quark distributions vanish. It is interesting to investigate a physics mechanism to create a finite tensor-polarized antiquark distribution.
We show that resonant processes during multi-field inflation can generate a large curvature perturbation on small scales. This perturbation naturally leads to the formation of primordial black holes that may constitute dark matter, as well as to the production of stochastic induced gravitational waves in the deci-Hz band. Such waves are within reach of future space-based interferometers such as LISA, DECIGO and BBO. In addition, primordial black hole binaries formed at late times produce merger gravitational waves that can be probed by the resonant cavity experiments in addition to DECIGO and BBO.
This paper defines Spoof Diarization as a novel task in the Partial Spoof (PS) scenario. It aims to determine what spoofed when, which includes not only locating spoof regions but also clustering them according to different spoofing methods. As a pioneering study in spoof diarization, we focus on defining the task, establishing evaluation metrics, and proposing a benchmark model, namely the Countermeasure-Condition Clustering (3C) model. Utilizing this model, we first explore how to effectively train countermeasures to support spoof diarization using three labeling schemes. We then utilize spoof localization predictions to enhance the diarization performance. This first study reveals the high complexity of the task, even in restricted scenarios where only a single speaker per audio file and an oracle number of spoofing methods are considered. Our code is available at this https URL.
The IKKT matrix model has been investigated as a promising nonperturbative formulation of superstring theory. One of the recent developments concerning this model is the discovery of the dual supergravity solution corresponding to the model obtained after supersymmetry-preserving mass deformation, which is dubbed the polarized IKKT model. Here we perform Monte Carlo simulations of this model in the case of matrix size N = 2 for a wide range of the deformation parameter Omega. While we reproduce precisely the known result for the partition function obtained by the localization method developed for supersymmetric theories, we also calculate the observables, which were not accessible by previous work, in order to probe the spacetime structure emergent from the dominant matrix configurations. In particular, we find that the saddle point corresponding to the original IKKT model is smoothly connected to the saddle represented by the fuzzy sphere dominant at large Omega, whereas the dominant configurations become diverging commuting matrices at small Omega.
National Astronomical Observatory of JapanUniversity College London logoUniversity College LondonOsaka University logoOsaka Universitythe University of Tokyo logothe University of TokyoKyoto University logoKyoto UniversitySokendaiRIKEN logoRIKENNASA Goddard Space Flight Center logoNASA Goddard Space Flight CenterUniversity of Maryland logoUniversity of MarylandInstitute of Statistical MathematicsUniversity of Virginia logoUniversity of VirginiaSwinburne University of TechnologyThe University of Western AustraliaAstrobiology CenterKagoshima UniversityLowell ObservatoryJapan Aerospace Exploration AgencyU.S. Naval ObservatoryHirosaki Universityat DresdenCalifornia State University-SacramentoTechnische Universit
Japan Astrometry Satellite Mission for INfrared Exploration (JASMINE) is a planned M-class science space mission by the Institute of Space and Astronautical Science, the Japan Aerospace Exploration Agency. JASMINE has two main science goals. One is the Galactic archaeology with Galactic Center Survey, which aims to reveal the Milky Way's central core structure and formation history from Gaia-level (~25 μ\muas) astrometry in the Near-Infrared (NIR) Hw-band (1.0-1.6 μ\mum). The other is the Exoplanet Survey, which aims to discover transiting Earth-like exoplanets in the habitable zone from NIR time-series photometry of M dwarfs when the Galactic center is not accessible. We introduce the mission, review many science objectives, and present the instrument concept. JASMINE will be the first dedicated NIR astrometry space mission and provide precise astrometric information of the stars in the Galactic center, taking advantage of the significantly lower extinction in the NIR. The precise astrometry is obtained by taking many short-exposure images. Hence, the JASMINE Galactic center survey data will be valuable for studies of exoplanet transits, asteroseismology, variable stars and microlensing studies, including discovery of (intermediate mass) black holes. We highlight a swath of such potential science, and also describe synergies with other missions.
A two-level quantum system evolving under a time-independent Hamiltonian produces oscillatory measurement probabilities. The estimation of the associated frequency is a cornerstone problem in quantum metrology, sensing, calibration and control. In this work, we tackle this task by introducing WES: a Window Expansion Strategy for low cost adaptive Bayesian experimental design. WES employs empirical cost-reduction techniques to keep the optimization overhead low, curb scaling problems, and enable high degrees of parallelism. Unlike previous heuristics, it offers adjustable classical processing costs that determine the performance standard. As a benchmark, we analyze the performance of widely adopted heuristics, comparing them with the fundamental limits of metrology and a baseline random strategy. Numerical simulations show that WES delivers the most reliable performance and fastest learning rate, saturating the Heisenberg limit.
We show that the regularization of the second order pole in the pole inflation can induce the increase of nsn_s, which may be important after the latest data release of cosmic microwave background (CMB) observation by Atacama Cosmology Telescope (ACT). Pole inflation is known to provide a unified description of attractor models that they can generate a flat plateau for inflation given a general potential. Recent ACT observation suggests that the constraint on the scalar spectral index nsn_s at CMB scale may be shifted to a larger value than the predictions in the Starobinsky model, the Higgs inflation, and the α\alpha-attractor model, which motivates us to consider the modification of the pole inflation. We find that if we regularize the second order pole in the kinetic term such that the kinetic term becomes regular for all field range, we can generally increase nsn_s because the potential in the large field regime will be lifted. We have explicitly demonstrated that this type of regularized pole inflation can naturally arise from the Einstein-Cartan formalism, and the inflationary predictions are consistent with the latest ACT data without spoiling the success of the α\alpha-attractor models.
We present the deepest optical images of the COSMOS field based on a joint dataset taken with Hyper Suprime-Cam (HSC) by the HSC Subaru Strategic Program (SSP) team and the University of Hawaii (UH). The COSMOS field is one of the key extragalactic fields with a wealth of deep, multi-wavelength data. However, the current optical data are not sufficiently deep to match with, e.g., the UltraVista data in the near-infrared. The SSP team and UH have joined forces to produce very deep optical images of the COSMOS field by combining data from both teams. The coadd images reach depths of g=27.8, r=27.7, i=27.6, z=26.8, and y=26.2 mag at 5 sigma for point sources based on flux uncertainties quoted by the pipeline and they cover essentially the entire COSMOS 2 square degree field. The seeing is between 0.6 and 0.9 arcsec on the coadds. We perform several quality checks and confirm that the data are of science quality; ~2% photometry and 30 mas astrometry. This accuracy is identical to the Public Data Release 1 from HSC-SSP. We make the joint dataset including fully calibrated catalogs of detected objects available to the community at this https URL
We revisit the upper bound on the annihilation cross-section, σv\langle\sigma v\rangle of a stable dark matter (DM) of mass 5×10210145\times10^2-10^{14} GeV by considering five different channels: W+WW^+W^-, bbˉb\bar{b}, μ+μ\mu^+\mu^-, τ+τ\tau^+\tau^-, and e+ee^+e^-. We use the observed electron and positron fluxes from CALET, DAMPE, HESS, positron flux from AMS-02, and gamma-ray flux from HAWC, GRAPES-3, CASA-MIA to constrain the annihilation cross-section. We also consider unstable DM of mass 103101610^3-10^{16}~GeV decaying to W+WW^+W^-, bbˉb\bar{b}, μ+μ\mu^+\mu^-, τ+τ\tau^+\tau^-, and e+ee^+e^- and derive the corresponding lower bound on the DM lifetime, τDM\tau_{\rm DM}. We find that the latest data from CALET gives a stringent constraint on σv\langle\sigma v\rangle in the low DM mass regime. For a typical DM mass of 1 TeV, we show that σvDM DMμ+μO(1024) cm3/s\langle\sigma v\rangle_{{\rm DM~DM}\rightarrow\mu^+\mu^-}\gtrsim\mathcal{O}(10^{-24})~\rm cm^3/s is disfavored. On the other hand in the low mass regime, the AMS-02 gives a much stringent limit on the DM lifetime, excluding τDMμ+μO(1027)\tau_{\rm DM\rightarrow\mu^+\mu^-}\lesssim\mathcal{O}(10^{27}) s for a 1 TeV mass of DM. In the high mass regime, typically MDMO(105)M_{\rm DM}\gtrsim\mathcal{O}(10^5) GeV, HAWC and CASA-MIA give the strongest constraints on σv\langle\sigma v\rangle and τDM\tau_{\rm DM}.
This study develops and validates an ensemble conditional Generative Adversarial Network (GAN) to reduce noise in weak gravitational lensing mass maps from Subaru Hyper Suprime-Cam data, effectively preserving non-Gaussian cosmological information. The denoised maps accurately recover the one-point probability distribution functions and improve the detection of galaxy clusters, demonstrating robustness against observational systematic uncertainties and consistency with standard cosmological models.
Researchers applied conditional adversarial networks (CANs) to reduce shape noise in weak gravitational lensing mass maps, enhancing the precision of cosmological parameter inference. This deep learning approach led to a 30-40% improvement in constraints on key cosmological parameters like AsA_s and Ωm0\Omega_{m0} when using one-point probability distributions.
Vibrational sum frequency generation (SFG) spectroscopy is a powerful technique for investigating molecular structures, orientations, and dynamics at surfaces. However, its spatial resolution is fundamentally restricted to the micrometer scale by the optical diffraction limit. Tip-enhanced SFG (TE-SFG) using a scanning tunneling microscope has been developed to overcome this limitation. The acquired spectra exhibit characteristic dips originating from vibrational responses located within the strong broadband non-resonant background (NRB), which distorts and obscures the molecular signals. By making the second pulse temporally asymmetric and introducing a controlled delay between the first and second laser pulses, the NRB was effectively suppressed, which in turn amplified the vibrational response through interference and facilitated the detection of weak vibrational signals. This interference also made the technique phase-sensitive, enabling the determination of absolute molecular orientations. Furthermore, forward- and backward-scattered signals were simultaneously detected, conclusively confirming that the observed signals originated from tip enhancement rather than far-field contributions. Finally, the signal enhancement factor in TE-SFG was estimated to be 6.3×1061.3×1076.3\times 10^6-1.3\times 10^7, based on the experimental data. This phase-sensitive TE-SFG technique overcomes the optical diffraction limit and enables the investigation of molecular vibrations at surfaces with unprecedented detail.
The asymmetric skew divergence smooths one of the distributions by mixing it, to a degree determined by the parameter λ\lambda, with the other distribution. Such divergence is an approximation of the KL divergence that does not require the target distribution to be absolutely continuous with respect to the source distribution. In this paper, an information geometric generalization of the skew divergence called the α\alpha-geodesical skew divergence is proposed, and its properties are studied.
We present the JWST discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS+53.13485+53.13485-27.8208827.82088 with a host spectroscopic redshift of 2.903±0.0072.903\pm0.007. The transient was identified in deep James Webb Space Telescope (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic followup with NIRCam and NIRSpec, respectively, confirm the redshift and yield UV-NIR light-curve, NIR color, and spectroscopic information all consistent with a Type Ia classification. Despite its classification as a likely SN Ia, SN 2023adsy is both fairly red (E(B-V)0.9\sim0.9) despite a host galaxy with low-extinction and has a high Ca II velocity (19,000±2,00019,000\pm2,000km/s) compared to the general population of SNe Ia. While these characteristics are consistent with some Ca-rich SNe Ia, particularly SN 2016hnk, SN 2023adsy is intrinsically brighter than the low-z Ca-rich population. Although such an object is too red for any low-z cosmological sample, we apply a fiducial standardization approach to SN 2023adsy and find that the SN 2023adsy luminosity distance measurement is in excellent agreement (1σ\lesssim1\sigma) with Λ\LambdaCDM. Therefore unlike low-z Ca-rich SNe Ia, SN 2023adsy is standardizable and gives no indication that SN Ia standardized luminosities change significantly with redshift. A larger sample of distant SNe Ia is required to determine if SN Ia population characteristics at high-z truly diverge from their low-z counterparts, and to confirm that standardized luminosities nevertheless remain constant with redshift.
Researchers from National Institute of Informatics, Feng Chia University, Lancaster University, and the University of Melbourne developed a cybernetic framework for detecting and unlearning neural backdoors in AI models without needing original training data. The approach, which utilizes psychometric analysis and chaotic projection of artificial mental imagery, achieved significantly reduced attack success rates while preserving model fidelity and produced more accurate reverse-engineered backdoor triggers compared to benchmark methods.
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