{"title":"On the stochastic Allen–Cahn equation on networks with multiplicative noise","authors":"M. Kov'acs, E. Sikolya","doi":"10.14232/EJQTDE.2021.1.7","DOIUrl":"https://doi.org/10.14232/EJQTDE.2021.1.7","url":null,"abstract":"We consider a system of stochastic Allen-Cahn equations on a finite network represented by a finite graph. On each edge in the graph a multiplicative Gaussian noise driven stochastic Allen-Cahn equation is given with possibly different potential barrier heights supplemented by a continuity condition and a Kirchhoff-type law in the vertices. Using the semigroup approach for stochastic evolution equations in Banach spaces we obtain existence and uniqueness of solutions with sample paths in the space of continuous functions on the graph. We also prove more precise space-time regularity of the solution.","PeriodicalId":8445,"journal":{"name":"arXiv: Analysis of PDEs","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73238226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Travelling wave solutions for gravity fingering in porous media flows.","authors":"K. Mitra, A. Ratz, B. Schweizer","doi":"10.13140/RG.2.2.23096.78083","DOIUrl":"https://doi.org/10.13140/RG.2.2.23096.78083","url":null,"abstract":"We study an imbibition problem for porous media. When a wetted layer is above a dry medium, gravity leads to the propagation of the water downwards into the medium. In experiments, the occurrence of fingers was observed, a phenomenon that can be described with models that include hysteresis. In the present paper, we describe a single finger in a moving frame and set up a free boundary problem to describe the shape and the motion of one finger that propagates with a constant speed. We show the existence of solutions to the travelling wave problem and investigate the system numerically.","PeriodicalId":8445,"journal":{"name":"arXiv: Analysis of PDEs","volume":"43 338 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77385862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dual variational methods for an indefinte nonlinear Helmholtz equation","authors":"Rainer Mandel, Dominic Scheider, Tolga A Yeşil","doi":"10.5445/IR/1000126434/V2","DOIUrl":"https://doi.org/10.5445/IR/1000126434/V2","url":null,"abstract":"We prove new existence results for a Nonlinear Helmholtz equation with sign-changing nonlinearity of the form $$-Delta u-k^2u=Q(x)|u|^{p-2}u,quad uin W^{2,p}(mathbb{R}^N)$$ with $k>0, Nge3,pinleft[frac{2(N+1)}{N-1},frac{2N}{N-2}right]$ and $Qin L^infty(mathbb{R}^N)$. Due to sign-changes of $Q$, our solutions have infinite Morse-Index in the \u0000corresponding dual variational formulation.","PeriodicalId":8445,"journal":{"name":"arXiv: Analysis of PDEs","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77061729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Potential well theory for the derivative nonlinear\u0000Schrödinger equation","authors":"M. Hayashi","doi":"10.2140/apde.2021.14.909","DOIUrl":"https://doi.org/10.2140/apde.2021.14.909","url":null,"abstract":"We consider the following nonlinear Schrodinger equation of derivative type: begin{equation}i partial_t u + partial_x^2 u +i |u|^{2} partial_x u +b|u|^4u=0 , quad (t,x) in mathbb{R}timesmathbb{R}, b inmathbb{R}. end{equation} If $b=0$, this equation is known as a gauge equivalent form of well-known derivative nonlinear Schrodinger equation (DNLS), which is mass critical and completely integrable. The equation can be considered as a generalized equation of DNLS while preserving mass criticality and Hamiltonian structure. For DNLS it is known that if the initial data $u_0in H^1(mathbb{R})$ satisfies the mass condition $| u_0|_{L^2}^2 <4pi$, the corresponding solution is global and bounded. In this paper we first establish the mass condition on the equation for general $binmathbb{R}$, which is exactly corresponding to $4pi$-mass condition for DNLS, and then characterize it from the viewpoint of potential well theory. We see that the mass threshold value gives the turning point in the structure of potential wells generated by solitons. In particular, our results for DNLS give a characterization of both $4pi$-mass condition and algebraic solitons.","PeriodicalId":8445,"journal":{"name":"arXiv: Analysis of PDEs","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79004513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}