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Huaqiao Wang

Publications and source records attributed to Huaqiao Wang.

At least 19 recordsLinked to original sources
arXiv2025

Weak Martingale Solutions of the Stochastic Schrödinger-Poisson-Landau-Lifshitz-Gilbert System

The Schrödinger-Poisson-Landau-Lifshitz-Gilbert (SPLLG) system can characterize the spin transfer torque mechanism transferring the spin angular momentum to the magnetization dynamics through spin-magnetization coupling. We study the three-dimensional stochastic SPLLG system driven by a multiplicative stochastic force containing a continuous noise and a small jump noise. We establish the existence of weak martingale solutions based on the penalized functional technique, the Faedo-Galerkin approximation, stochastic compactness method, and a careful identification of the limit. Due to the strong coupling and strong nonlinearity caused by the SPLLG system and stochastic effects, some crucial difficulties have been encountered in obtaining energy estimates and avoiding non-negativity of the test function. We mainly utilize the structure of equations and the property of martingales developing the new energy estimates, and apply the three-layer approximation to overcome these difficulties. In particular, we extend the results by Z. Brzeźniak and U. Manna (Comm. Math. Phys., 2019) and by L.H. Chai, C.J. Garc\'ıa-Cervera and X. Yang (Arch. Ration. Mech. Anal., 2018) to both the stochastic case and the coupling case.

math.PR↗
arXiv2025

Non-uniqueness of weak solutions to the 3D Hall-MHD equations on the plane

We prove the non-uniqueness of weak solutions with non-trivial magnetic fields to the 3D Hall-MHD equations on the plane in the space $C^0_t L_x^2$ through the convex integration scheme and by constructing new errors and new intermittent flows. In particular, based on the construction of 3D intermittent flows, we obtain the $2\frac{1}{2}$D Mikado flows through a projection onto the plane. Moreover, we prove that the constructed weak solution do not conserve the magnetic helicity and find that weak solutions of the ideal Hall-MHD equations in $C^{\barβ}_{t,x}$ ($\barβ>0$) are the strong vanishing viscosity and resistive limit of weak solutions to the Hall-MHD equations.

math.AP↗
arXiv2023

Weak solutions to the Hall-MHD equations whose singular sets in time have Hausdorff dimension strictly less than 1

In this paper, we focus on the three-dimensional hyper viscous and resistive Hall-MHD equations on the torus, where the viscous and resistive exponent $α\in [ρ, 5/4)$ with a fixed constant $ρ\in (1,5/4)$. We prove the non-uniqueness of a class of weak solutions to the Hall-MHD equations, which have bounded kinetic energy and are smooth in time outside a set whose Hausdorff dimension strictly less than 1. The proof is based on the construction of the non-Leray-Hopf weak solutions via a convex integration scheme.

math.AP↗
arXiv2023

Global well-posedness of smooth solutions to the Landau-Lifshitz-Slonczewski equation

In this paper, we mainly consider the global solvability of smooth solutions for the Cauchy problem of the three-dimensional Landau-Lifshitz-Slonczewski equation in the Morrey space. We derive the covariant complex Ginzburg-Landau equation by using moving frames to address the nonlinear parts. Applying the semigroup estimates and energy methods, we extend local classical solutions to global solutions and prove the boundedness of $\|\nabla\boldsymbol{m}\|_{L^{\infty}(\mathbb{R}^{3})}$, where $\boldsymbol{m}$ is the magnetic intensity. Moreover, we obtain a global weak solution by using an approximation result and improve the regularity of the obtained solution by the regularity theory. Finally, we establish the existence and uniqueness of global smooth solutions under some conditions on $\nabla\boldsymbol{m}_{0}$ and the density of the spin-polarized current.

math.AP↗
arXiv2023

Global existence of strong solutions to the Landau-Lifshitz-Slonczewski equation

In this paper, we focus on the existence of strong solutions for the Cauchy problem of the three-dimensional Landau-Lifshitz-Slonczewski equation. We construct a new combination of Bourgain space and Lebesgue space where linear and nonlinear estimates can be closed by applying frequency decomposition and energy methods. Finally, we establish the existence and uniqueness of the global strong solution provided that the initial data belongs to Besov space $\dot{B}^{\frac{n}{2}}_Ω$.

math.AP↗
arXiv2022

Stochastic Cahn-Hilliard-Navier-Stokes equations with the dynamic boundary: Martingale weak solution, Markov selection

The existence of global martingale weak solution for the 2D and 3D stochastic Cahn-Hilliard-Navier-Stokes equations driven by multiplicative noise in a smooth bounded domain is established. In particular, the system is supplied with the dynamic boundary condition which accounts for the interaction between the fluid components and the rigid walls. The proof is completed by a three-level approximate scheme combining a fixed point argument and the stochastic compactness argument, overcoming challenges from strong nonlinearity, dynamic boundary and random effect. Then, we prove the existence of an almost surely Markov selection to the associated martingale problem following the abstract framework established by F. Flandoli and M. Romito.

math.PR↗
arXiv2022

Global Classical Solutions to the viscous two-phase flow model with slip Boundary Conditions in 3D Exterior Domains

We consider the two-phase flow model with slip boundary condition in a 3D exterior domains whose boundary is smooth. We establish the global existence of classical solutions of this system provided that the initial energy is suitably small. Moreover, the pressure has large oscillations and contains vacuum states when the initial pressure allows large oscillations and a vacuum. Finally, we also obtain the large-time behavior of the classical solutions.

math.AP↗
arXiv2022

Strong solutions of the Landau-Lifshitz-Bloch equation in Besov space

We focus on the existence and uniqueness of the three-dimensional Landau-Lifshitz-Bloch equation supplemented with the initial data in Besov space $\dot{B}_{2,1}^{\frac{3}{2}}$. Utilizing a new commutator estimate, we establish the local existence and uniqueness of strong solutions for any initial data in $\dot{B}_{2,1}^{\frac{3}{2}}$. When the initial data is small enough in $\dot{B}_{2,1}^{\frac{3}{2}}$, we obtain the global existence and uniqueness. Furthermore, we also establish a blow-up criterion of the solution to the Landau-Lifshitz-Bloch equation and then we prove the global existence of strong solutions in Sobolev space under a new condition based on the blow-up criterion.

math.AP↗
arXiv2022

On instability and stability of a quasi-linear hyperbolic-parabolic model for vasculogenesis

In this paper, we are concerned with the instability and stability of a quasi-linear hyperbolic-parabolic system modeling vascular networks. Under the assumption that the pressure satisfies $\frac{νP'(\barρ)}{γ\barρ} < β$, we first show that the steady-state is linear unstable (i.e., the linear solution grows in time in $L^2$) by constructing an unstable solution. Then based on the lower grow estimates on the solution to the linear system, we prove that the steady-state is nonlinear unstable in the sense of Hadamard. On the contrary, if the pressure satisfies $\frac{νP'(\barρ)}{γ\barρ} > β$, we establish the global existence for small perturbations and the optimal convergent rates for all-order derivatives of the solution by slightly getting rid of the condition proposed in [Liu-Peng-Wang, SIAM J. MATH. ANAL 54:1313--1346, 2022].

math.AP↗
arXiv2022

The Landau-Lifshitz-Bloch equation on the thin film

We consider the initial boundary value problem of Landau-Lifshitz-Bloch equation on three-dimensional ferromagnetic films, where the effective field contains the stray field controlled by Maxwell equation and the exchange field contains exchange constant. In this paper, we establish the existence of weak solutions of the equation by using the Faedo-Galerkin approximation method. We also derive its two-dimensional limit equation in a mathematically rigorous way when the film thickness tends to zero under appropriate compactness conditions. Moreover, we obtain an equation that can better describe the magnetic dynamic behavior of ferromagnetic films with negligible thickness at high temperature.

math.AP↗
arXiv2021

Well-posedness for the stochastic electrokinetic flow

We consider the stochastic electrokinetic flow in a smooth bounded domain $\mathcal{D}$, modelled by a Nernst-Planck-Navier-Stokes system with a blocking boundary conditions for ionic species concentrations, perturbed by multiplicative noise. Several results are established in this paper. In both $2d$ and $3d$ cases, we establish the global existence of weak martingale solution which is weak in both PDEs and probability sense, and also the existence and uniqueness of the maximal strong pathwise solution which is strong in PDEs and probability sense. Particularly, we show that the maximal pathwise solution is global one in $2d$ case without the restriction of smallness of initial data.

math.AP↗
arXiv2021

Global existence and decay rates for a generic compressible two-fluid model

We investigate global existence and optimal decay rates of a generic non-conservative compressible two--fluid model with general constant viscosities and capillary coefficients.The main novelty of this work is three--fold: First, for any integer $\ell\geq3$, we show that the densities and velocities converge to their corresponding equilibrium states at the $L^2$ rate $(1+t)^{-\frac{3}{4}}$, and the $k$($\in [1, \ell]$)--order spatial derivatives of them converge to zero at the $L^2$ rate $(1+t)^{-\frac{3}{4}-\frac{k}{2}}$, which are the same as ones of the compressible Navier--Stokes system, Navier--Stokes--Korteweg system and heat equation. Second, the linear combination of the fraction densities ($β^+α^+ρ^++β^-α^-ρ^-$) converges to its corresponding equilibrium state at the $L^2$ rate $(1+t)^{-\frac{3}{4}}$, and its $k$($\in [1, \ell]$)--order spatial derivative converges to zero at the $L^2$ rate $(1+t)^{-\frac{3}{4}-\frac{k}{2}}$, but the fraction densities ($α^\pmρ^\pm$) themselves converge to their corresponding equilibrium states at the $L^2$ rate $(1+t)^{-\frac{1}{4}}$, and the $k$($\in [1, \ell]$)--order spatial derivatives of them converge to zero at the $L^2$ rate $(1+t)^{-\frac{1}{4}-\frac{k}{2}}$, which are slower than ones of their linear combination ($β^+α^+ρ^++β^-α^-ρ^-$) and the densities. We think that this phenomenon should owe to the special structure of the system. Finally, for well--chosen initial data, we also prove the lower bounds on the decay rates, which are the same as those of the upper decay rates. Therefore, these decay rates are optimal for the compressible two--fluid model.

math.AP↗
arXiv2021

Martingale solutions for the compressible MHD systems with stochastic external forces

In this paper we consider the three-dimensional compressible MHD system with stochastic external forces in a bounded domain. We obtain the existence of martingale solution which is a weak solution for the fluid variables, the Brownian motion on a probability space. The construction of the solution is based on the Galerkin approximation method, stopping time, the compactness method and Jakubowski Skorokhod theorem, etc.

math.AP↗
arXiv2021

Derivation of the Hall-MHD equations from the Navier-Stokes-Maxwell equations

By using a set of scaling limits, the authors in \cite{ADFL,SS} proposed a framework of deriving the Hall-MHD equations from the two-fluids Euler-Maxwell equations for electrons and ions. In this paper, we derive the Hall-MHD equations from the Navier-Stokes-Maxwell equations with generalized Ohm's law in a mathematically rigorous way via the spectral analysis and energy methods.

math.AP↗
arXiv2021

On non-resistive limit of 1D MHD equations with no vacuum at infinity

In this paper, we consider the Cauchy problem for the one-dimensional compressible isentropic magnetohydrodynamic (MHD) equations with no vacuum at infinity, but the initial vacuum can be permitted inside the region. By deriving a priori $ν$ (resistivity coefficient)-independent estimates, we establish the non-resistive limit of the global strong solutions with large initial data. Moreover, as a by-product, the global well-posedness of strong solutions for both the compressible resistive MHD equations and non-resistive MHD equations are also established, respectively.

math.AP↗
arXiv2020

Optimal decay rates of a non-conservative compressible two-phase fluid model

We are concerned with the time decay rates of strong solutions to a non-conservative compressible viscous two-phase fluid model in the whole space R3. Compared to the previous related works, the main novelty of this paper lies in the fact that it provides a general framework that can be used to extract the optimal decay rates of the solution as well as its all-order spatial derivatives from one-order to the highest-order, which are the same as those of the heat equation. Furthermore, for well-chosen initial data, we also show the lower bounds on the decay rates. Our methods mainly consist of Hodge decomposition, low-frequency and high-frequency decomposition, delicate spectral analysis and energy method based on finite induction.

math.AP↗
arXiv2020

Well-posedness for the Cahn-Hilliard-Navier-Stokes equation with random initial data

In this paper, we consider the almost sure well-posedness of the Cauchy problem to the Cahn-Hilliard-Navier-Stokes equation with a randomization initial data on a torus $\mathbb{T}^3$. First, we prove the local existence and uniqueness of solution. Furthermore, we prove the global existence and uniqueness of solution and give the relative probability estimate under the condition of small initial data.

math.AP↗