arXiv subjects

Chongyang Ren

Publications and source records attributed to Chongyang Ren.

7 recordsLinked to original sources

arXiv2026

Kinetic Fokker--Planck Equations with Drifts in a Supercritical Range

We investigate kinetic Fokker--Planck equations with rough divergence-free drifts in anisotropic mixed Lebesgue spaces. The divergence-free structure yields an energy cancellation that remains effective under kinetic localization. Combining this cancellation with anisotropic regularization estimates and a De Giorgi iteration, we establish local boundedness for weak subsolutions and, consequently, global well-posedness for the Cauchy problem in a scaling-supercritical regime.

math.AP↗

arXiv2026

Well-posedness and regularity of stochastic heat equations on moving domains

In this paper we investigate stochastic heat equations driven by multiplicative noise on moving domains. We establish the well-posedness within a nonhomogeneous variational framework. Furthermore, by combining stochastic De Giorgi iteration with Dirichlet parabolic estimates, we obtain the H\"older regularity of the solutions.

math.PR↗

arXiv2026

The Non-Gaussian to Gaussian Transition: Pointwise Heat Kernel Estimates and Optimal Convergence Rates

We establish uniform pointwise estimates for the densities of a family of $\alpha$-stable processes with respect to the index $\alpha \in [\alpha_0,2]$ for some $\alpha_0>0$. In addition, we estimate the difference between the heat kernels of non-local and local operators, showing that it is controlled by the rate $2-\alpha$. Both estimates (see Proposition 2.4) are new to the literature. Furthermore, as an application, we achieve the optimal rate $2-\alpha$ for the pointwise estimate between the transition probabilities, as well as for the (weighted) total variation and Kantorovich distances between the invariant measures, of non-Gaussian and Gaussian diffusion. These results are obtained under the assumption that the drifts are locally $\beta$-H\"older continuous, with the latter additionally requiring dissipativity. The results on transition probabilities (see Theorem 2.3) are novel, while those on invariant measures (see Theorem 2.7) significantly extend the existing literature.

math.PR↗

arXiv2024

Supercritical McKean-Vlasov SDE driven by cylindrical $\alpha$-stable process

In this paper, we study the following supercritical McKean-Vlasov SDE, driven by a symmetric non-degenerate cylindrical $\alpha$-stable process in $\mathbb{R}^d$ with $\alpha \in (0,1)$: $$ \mathord{{\rm d}} X_t = (K * \mu_{t})(X_t)\mathord{{\rm d}}t + \mathord{{\rm d}} L_t^{(\alpha)}, \quad X_0 = x \in \mathbb{R}^d, $$ where $K: \mathbb{R}^d \to \mathbb{R}^d$ is a $\beta$-order H\"older continuous function, and $\mu_t$ represents the time marginal distribution of the solution $X$. We establish both strong and weak well-posedness under the conditions $\beta \in (1 - \alpha/2, 1)$ and $\beta \in (1 - \alpha, 1)$, respectively. Additionally, we demonstrate strong propagation of chaos for the associated interacting particle system, as well as the convergence of the corresponding Euler approximations. In particular, we prove a commutation property between the particle approximation and the Euler approximation.

math.PR↗

arXiv2024

Investigating the Potential of LS 5039 as a Triple System Using Fermi-LAT Data

LS 5039 is one of a handful of $γ$-ray binary systems in the Milky Way, comprising a pulsar and a massive O-type companion star with an orbital period of 3.9 day. Recently, we conducted a data analysis using approximately 16 year of Fermi-LAT observations, spanning from 2008 August 4 to 2024 July 8. In our timing analysis, we discovered two new periodic signals with frequencies higher and lower than the known orbital period. The higher-frequency signal has a period of 3.63819 day with a 7.1$σ$ confidence level, while the lower-frequency signal has a period of 4.21654 day with a 6.3$σ$ confidence level. Additionally, in data from the High Energy Stereoscopic System of Cherenkov Telescopes, two potential signals with periods similar to the two newly discovered ones. Considering that these two signals fall within the same frequency interval as the orbital period, we suggest the possibility of a third body orbiting the barycenter of the LS 5039 binary system, with the new periodic signals arising from specific frequency combinations of the two orbital periods.

astro-ph.HE↗

arXiv2024

Heat kernel estimates for kinetic SDEs with drifts being unbounded and in Kato's class

In this paper we investigate the existence and uniqueness of weak solutions for kinetic stochastic differential equations with Hölder diffusion and unbounded singular drifts in Kato's class. Moreover, we also establish sharp two-sided estimates for the density of the solution. In particular, the drift $b$ can be in the mixed $L^q_tL^{p_1}_{x_1}L^{p_2}_{x_2}$ space with $\frac2q+\frac{d}{p_1}+\frac{3d}{p_2}<1$. As an application, we show the existence and uniqueness of weak solution to a second order singular interacting particle system in ${\mathbb R}^{d N}$.

math.PR↗

arXiv2023

A Possible Optical Quasi-periodic Oscillation of 134~day in the Radio-loud Narrow-line Seyfert 1 Galaxy TXS 1206+549 at $z=1.34$

Here we report an optical quasi-periodic oscillation (QPO) with a period of $\sim$134~day detected in g- and r-band light curves of a narrow-line Seyfert 1 galaxy TXS 1206+549 at redshift of 1.34 with the data from the Zwicky Transient Facility (ZTF) observations. After considering the trial factor, the significance levels in the two bands are 3.1 $σ$ and 2.6 $σ$, respectively. The QPO signal presents about 10 cycles ranging from 2018 March to 2021 December lasting $\sim$4 year. A near-sinusoidal profile also appears in the folded light curves by a phase-resolved analysis. Interestingly, in the simultaneous light curve as the time scale of ZTF observations, a potential periodic signal with similar period is detected in the o-band light curve from the Asteroid Terrestrial-Impact Last Alert System data, additionally a weak peak is also detected at the similar period in the gamma-ray light curve obtained from the \emph{Fermi} Gamma-ray Space Telescope data. Some potential origins of periodicities in active galactic nuclei are discussed for the QPO reported here.

astro-ph.HE↗