{"title":"Pathwise uniqueness for singular stochastic Volterra equations with Hölder coefficients","authors":"David J. Prömel, David Scheffels","doi":"10.1007/s40072-024-00335-y","DOIUrl":"https://doi.org/10.1007/s40072-024-00335-y","url":null,"abstract":"<p>Pathwise uniqueness is established for a class of one-dimensional stochastic Volterra equations driven by Brownian motion with singular kernels and Hölder continuous diffusion coefficients. Consequently, the existence of unique strong solutions is obtained for this class of stochastic Volterra equations.</p>","PeriodicalId":48569,"journal":{"name":"Stochastics and Partial Differential Equations-Analysis and Computations","volume":"105 4 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"BPHZ renormalisation and vanishing subcriticality asymptotics of the fractional $$Phi ^3_d$$ model","authors":"Nils Berglund, Yvain Bruned","doi":"10.1007/s40072-024-00331-2","DOIUrl":"https://doi.org/10.1007/s40072-024-00331-2","url":null,"abstract":"<p>We consider stochastic PDEs on the <i>d</i>-dimensional torus with fractional Laplacian of parameter <span>(rho in (0,2])</span>, quadratic nonlinearity and driven by space-time white noise. These equations are known to be locally subcritical, and thus amenable to the theory of regularity structures, if and only if <span>(rho > d/3)</span>. Using a series of recent results by the second named author, A. Chandra, I. Chevyrev, M. Hairer and L. Zambotti, we obtain precise asymptotics on the renormalisation counterterms as the mollification parameter <span>(varepsilon )</span> becomes small and <span>(rho )</span> approaches its critical value. In particular, we show that the counterterms behave like a negative power of <span>(varepsilon )</span> if <span>(varepsilon )</span> is superexponentially small in <span>((rho -d/3))</span>, and are otherwise of order <span>(log (varepsilon ^{-1}))</span>. This work also serves as an illustration of the general theory of BPHZ renormalisation in a relatively simple situation.</p>","PeriodicalId":48569,"journal":{"name":"Stochastics and Partial Differential Equations-Analysis and Computations","volume":"26 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Long-term dynamics of fractional stochastic delay reaction–diffusion equations on unbounded domains","authors":"Zhang Chen, Bixiang Wang","doi":"10.1007/s40072-024-00334-z","DOIUrl":"https://doi.org/10.1007/s40072-024-00334-z","url":null,"abstract":"<p>In this paper, we investigate the long-term dynamics of fractional stochastic delay reaction-diffusion equations on unbounded domains with a polynomial drift term of arbitrary order driven by nonlinear noise. We first define a mean random dynamical system in a Hilbert space for the solutions of the equation and prove the existence and uniqueness of weak pullback mean random attractors. We then establish the existence and regularity of invariant measures of the system under further conditions on the nonlinear delay and diffusion terms. We also prove the tightness of the set of all invariant measures of the equation when the time delay varies in a bounded interval. We finally show that every limit of a sequence of invariant measures of the delay equation must be an invariant measure of the limiting system as delay approaches zero. The uniform tail-estimates and the Ascoli–Arzelà theorem are used to derive the tightness of distribution laws of solutions in order to overcome the non-compactness of Sobolev embeddings on unbounded domains.</p>","PeriodicalId":48569,"journal":{"name":"Stochastics and Partial Differential Equations-Analysis and Computations","volume":"8 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Massimiliano Gubinelli, Martina Hofmanová, Nimit Rana
{"title":"Decay of correlations in stochastic quantization: the exponential Euclidean field in two dimensions","authors":"Massimiliano Gubinelli, Martina Hofmanová, Nimit Rana","doi":"10.1007/s40072-024-00328-x","DOIUrl":"https://doi.org/10.1007/s40072-024-00328-x","url":null,"abstract":"<p>We present two approaches to establish the exponential decay of correlation functions of Euclidean quantum field theories (EQFTs) via stochastic quantization (SQ). In particular we consider the elliptic stochastic quantization of the Høegh–Krohn (or <span>(exp (alpha phi )_2)</span>) EQFT in two dimensions. The first method is based on a path-wise coupling argument and PDE apriori estimates, while the second on estimates of the Malliavin derivative of the solution to the SQ equation.</p>","PeriodicalId":48569,"journal":{"name":"Stochastics and Partial Differential Equations-Analysis and Computations","volume":"123 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140940551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A weighted $$L_q(L_p)$$ -theory for fully degenerate second-order evolution equations with unbounded time-measurable coefficients","authors":"Ildoo Kim","doi":"10.1007/s40072-024-00330-3","DOIUrl":"https://doi.org/10.1007/s40072-024-00330-3","url":null,"abstract":"<p>We study the fully degenerate second-order evolution equation </p><span>$$begin{aligned} u_t=a^{ij}(t)u_{x^ix^j} +b^i(t) u_{x^i} + c(t)u+f, quad t>0, xin mathbb {R}^d end{aligned}$$</span>(0.1)<p>given with the zero initial data. Here <span>(a^{ij}(t))</span>, <span>(b^i(t))</span>, <i>c</i>(<i>t</i>) are merely locally integrable functions, and <span>((a^{ij}(t))_{d times d})</span> is a nonnegative symmetric matrix with the smallest eigenvalue <span>(delta (t)ge 0)</span>. We show that there is a positive constant <i>N</i> such that </p><span>$$begin{aligned}&int _0^{T} left( int _{mathbb {R}^d} left( |u(t,x)|+|u_{xx}(t,x) |right) ^{p} dx right) ^{q/p} e^{-qint _0^t c(s)ds} w(alpha (t)) delta (t) dt nonumber &le N int _0^{T} left( int _{mathbb {R}^d} left| fleft( t,xright) right| ^{p} dx right) ^{q/p} e^{-qint _0^t c(s)ds} w(alpha (t)) (delta (t))^{1-q} dt, end{aligned}$$</span>(0.2)<p>where <span>(p,q in (1,infty ))</span>, <span>(alpha (t)=int _0^t delta (s)ds)</span>, and <i>w</i> is Muckenhoupt’s weight.</p>","PeriodicalId":48569,"journal":{"name":"Stochastics and Partial Differential Equations-Analysis and Computations","volume":"24 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140829565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"$$L_p$$ -solvability and Hölder regularity for stochastic time fractional Burgers’ equations driven by multiplicative space-time white noise","authors":"Beom-Seok Han","doi":"10.1007/s40072-024-00329-w","DOIUrl":"https://doi.org/10.1007/s40072-024-00329-w","url":null,"abstract":"<p>This paper establishes <span>(L_p)</span>-solvability for stochastic time fractional Burgers’ equations driven by multiplicative space-time white noise: </p><span>$$begin{aligned} partial _t^alpha u = a^{ij}u_{x^ix^j} + b^{i}u_{x^i} + cu + {bar{b}}^i u u_{x^i} + partial _t^beta int _0^t sigma (u)dW_t,quad t>0;quad u(0,cdot ) = u_0, end{aligned}$$</span><p>where <span>(alpha in (0,1))</span>, <span>(beta < 3alpha /4+1/2)</span>, and <span>(d< 4--2(2beta -1)_+/alpha )</span>. The operators <span>(partial _t^alpha )</span> and <span>(partial _t^beta )</span> are the Caputo fractional derivatives of order <span>(alpha )</span> and <span>(beta )</span>, respectively. The process <span>(W_t)</span> is an <span>(L_2(mathbb {R}^d))</span>-valued cylindrical Wiener process, and the coefficients <span>(a^{ij}, b^i, c, {bar{b}}^{i})</span> and <span>(sigma (u))</span> are random. In addition to the uniqueness and existence of a solution, the Hölder regularity of the solution is also established. For example, for any constant <span>(T<infty )</span>, small <span>(varepsilon >0)</span>, and almost sure <span>(omega in varOmega )</span>, </p><span>$$begin{aligned} sup _{xin mathbb {R}^d}|u(omega ,cdot ,x)|_{C^{left[ frac{alpha }{2}left( left( 2-(2beta -1)_+/alpha -d/2 right) wedge 1 right) +frac{(2beta -1)_{-}}{2} right] wedge 1-varepsilon }([0,T])}<infty end{aligned}$$</span><p>and </p><span>$$begin{aligned} sup _{tle T}|u(omega ,t,cdot )|_{C^{left( 2-(2beta -1)_+/alpha -d/2 right) wedge 1 - varepsilon }(mathbb {R}^d)} < infty . end{aligned}$$</span><p>The Hölder regularity of the solution in time changes behavior at <span>(beta = 1/2)</span>. Furthermore, if <span>(beta ge 1/2)</span>, then the Hölder regularity of the solution in time is <span>(alpha /2)</span> times that in space.</p>","PeriodicalId":48569,"journal":{"name":"Stochastics and Partial Differential Equations-Analysis and Computations","volume":"57 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140808765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Temporal fractal nature of linearized Kuramoto–Sivashinsky SPDEs and their gradient in one-to-three dimensions","authors":"Wensheng Wang, Lu Yuan","doi":"10.1007/s40072-024-00327-y","DOIUrl":"https://doi.org/10.1007/s40072-024-00327-y","url":null,"abstract":"<p>Let <span>(U={U(t,x), (t,x)in mathring{{mathbb {R}}}_+times {mathbb {R}}^d})</span> and <span>(partial _{x}U={partial _{x}U(t,x), (t,x)in mathring{{mathbb {R}}}_+times {mathbb {R}}})</span> be the solution and gradient solution of the fourth order linearized Kuramoto–Sivashinsky (L-KS) SPDE, driven by the space-time white noise in one-to-three dimensional spaces, respectively. We use the underlying explicit kernels to prove the exact global temporal moduli and temporal LILs for the L-KS SPDEs and gradient, and utilize them to prove that the sets of temporal fast points where exceptional oscillation of <span>(U(cdot ,x))</span> and <span>(partial _{x}U(cdot ,x))</span> occur infinitely often are random fractals, and evaluate their Hausdorff dimensions and their hitting probabilities. It has been confirmed that these points of <span>(U(cdot ,x))</span> and <span>(partial _{x}U(cdot ,x))</span>, in time, are everywhere dense with power of the continuum almost surely, and their hitting probabilities are determined by the packing dimension <span>(dim _{_{p}}(B))</span> of the target set <i>B</i>.</p>","PeriodicalId":48569,"journal":{"name":"Stochastics and Partial Differential Equations-Analysis and Computations","volume":"220 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140196196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Weak error analysis for a nonlinear SPDE approximation of the Dean–Kawasaki equation","authors":"Ana Djurdjevac, Helena Kremp, Nicolas Perkowski","doi":"10.1007/s40072-024-00324-1","DOIUrl":"https://doi.org/10.1007/s40072-024-00324-1","url":null,"abstract":"<p>We consider a nonlinear SPDE approximation of the Dean–Kawasaki equation for independent particles. Our approximation satisfies the physical constraints of the particle system, i.e. its solution is a probability measure for all times (preservation of positivity and mass conservation). Using a duality argument, we prove that the weak error between particle system and nonlinear SPDE is of the order <span>(N^{-1-1/(d/2+1)}log N)</span>. Along the way we show well-posedness, a comparison principle, and an entropy estimate for a class of nonlinear regularized Dean–Kawasaki equations with Itô noise.</p>","PeriodicalId":48569,"journal":{"name":"Stochastics and Partial Differential Equations-Analysis and Computations","volume":"23 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Convergence of stratified MCMC sampling of non-reversible dynamics","authors":"Gabriel Earle, Jonathan C. Mattingly","doi":"10.1007/s40072-024-00325-0","DOIUrl":"https://doi.org/10.1007/s40072-024-00325-0","url":null,"abstract":"<p>We present a form of stratified MCMC algorithm built with non-reversible stochastic dynamics in mind. It can also be viewed as a generalization of the exact milestoning method or form of NEUS. We prove the convergence of the method under certain assumptions, with expressions for the convergence rate in terms of the process’s behavior within each stratum and large-scale behavior between strata. We show that the algorithm has a unique fixed point which corresponds to the invariant measure of the process without stratification. We will show how the convergence speeds of two versions of the algorithm, one with an extra eigenvalue problem step and one without, related to the mixing rate of a discrete process on the strata, and the mixing probability of the process being sampled within each stratum. The eigenvalue problem version also relates to local and global perturbation results of discrete Markov chains, such as those given by Van Koten, Weare et. al.</p>","PeriodicalId":48569,"journal":{"name":"Stochastics and Partial Differential Equations-Analysis and Computations","volume":"79 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140002011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Regularity of random elliptic operators with degenerate coefficients and applications to stochastic homogenization","authors":"Peter Bella, Michael Kniely","doi":"10.1007/s40072-023-00322-9","DOIUrl":"https://doi.org/10.1007/s40072-023-00322-9","url":null,"abstract":"<p>We consider degenerate elliptic equations of second order in divergence form with a symmetric random coefficient field <i>a</i>. Extending the work of Bella et al. (Ann Appl Probab 28(3):1379–1422, 2018), who established the large-scale <span>(C^{1,alpha })</span> regularity of <i>a</i>-harmonic functions in a degenerate situation, we provide stretched exponential moments for the minimal radius <span>(r_*)</span> describing the minimal scale for this <span>(C^{1,alpha })</span> regularity. As an application to stochastic homogenization, we partially generalize results by Gloria et al. (Anal PDE 14(8):2497–2537, 2021) on the growth of the corrector, the decay of its gradient, and a quantitative two-scale expansion to the degenerate setting. On a technical level, we demand the ensemble of coefficient fields to be stationary and subject to a spectral gap inequality, and we impose moment bounds on <i>a</i> and <span>(a^{-1})</span>. We also introduce the ellipticity radius <span>(r_e)</span> which encodes the minimal scale where these moments are close to their positive expectation value.\u0000</p>","PeriodicalId":48569,"journal":{"name":"Stochastics and Partial Differential Equations-Analysis and Computations","volume":"11 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139980086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}