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Time-fractional parabolic equations with a Caputo time derivative of order $\alpha\in(0,1)$ are discretized in time using continuous collocation methods. For such discretizations, we give sufficient conditions for existence and uniqueness…

Numerical Analysis · Mathematics 2024-07-01 Sebastian Franz , Natalia Kopteva

For the time-space fractional degenerate Keller-Segel equation \begin{equation*} \begin{cases} \partial _{t}^{\beta }u=-(-\Delta )^{\frac{\alpha}{2}}(\rho (v)u),& t>0\\ (-\Delta )^{\frac{\alpha}{2}} v+v=u,& t>0 \end{cases} \end{equation*}…

Analysis of PDEs · Mathematics 2022-11-17 Fei Gao , Hui Zhan

We consider the solution $u(x,t)$ of the Fisher-KPP equation $\partial_t u=\partial_x^2u+u-u^2$ centred around its $\alpha$-level $\mu_t^{(\alpha)}$ defined as $u(\mu_t^{(\alpha)},t)=\alpha$. It is well known that for an initial datum that…

Analysis of PDEs · Mathematics 2016-03-22 Julien Berestycki , Éric Brunet

In this paper, we consider the following fractional logarithmic Schr\"odinger equation \begin{equation*} \varepsilon^{2s}(-\Delta)^s u + V(x)u=u\log |u|^2\ \ \text{in}\ \R^N, \end{equation*} where $\varepsilon>0$, $N\ge 1$, $V(x)\in…

Analysis of PDEs · Mathematics 2022-02-01 Xiaoming An

In this article, we first employ the concentration compactness techniques to prove existence and stability results of standing waves for nonlinear fractional Schr\"{o}dinger-Choquard equation \[ i\partial_t\Psi + (-\Delta)^{\alpha}\Psi = a…

Analysis of PDEs · Mathematics 2017-06-13 Santosh Bhattarai

Given a selfadjoint magnetic Schr\"odinger operator \begin{equation*} H = ( i \partial + A(x) )^2 + V(x) \end{equation*} on $L^{2}(\mathbb{R}^n)$, with $V(x)$ strictly subquadratic and $A(x)$ strictly sublinear, we prove that the flow…

Analysis of PDEs · Mathematics 2026-01-26 Piero D'Ancona , Diego Fiorletta

This paper is concerned with the following fractional Schr\"{o}dinger equations involving critical exponents: \begin{eqnarray*} (-\Delta)^{\alpha}u+V(x)u=k(x)f(u)+\lambda|u|^{2_{\alpha}^{*}-2}u\quad\quad \mbox{in}\ \mathbb{R}^{N},…

Analysis of PDEs · Mathematics 2017-01-10 Xia Zhang , Binlin Zhang , Dušan Repovš

The Schr\"odinger eigenvalue problem is solved with the imaginary time propagation technique. The separability of the Hamiltonian makes the problem suitable for the application of splitting methods. High order fractional time steps of order…

Numerical Analysis · Mathematics 2015-06-15 Philipp Bader , Sergio Blanes , Fernando Casas

This paper deals with the following class of nonlocal Schr\"odinger equations $$ \displaystyle (-\Delta)^s u + u = |u|^{p-1}u \ \ \text{in} \ \mathbb{R}^N, \quad \text{for} \ s\in (0,1). $$ We prove existence and symmetry results for the…

Analysis of PDEs · Mathematics 2012-10-26 Serena Dipierro , Giampiero Palatucci , Enrico Valdinoci

In this paper, we develop a numerical scheme for the space-time fractional parabolic equation, i.e., an equation involving a fractional time derivative and a fractional spatial operator. Both the initial value problem and the…

Numerical Analysis · Mathematics 2017-08-18 Andrea Bonito , Wenyu Lei , Joseph E. Pasciak

We investigate a class of nonlinear time-space fractional Schr\"{o}dinger equations with nonlocal effects in both time and space. The time derivative is of Achar type, and the space operator is a $\phi(-\Delta)$-type operator defined via a…

Analysis of PDEs · Mathematics 2026-05-25 Yong Zhen Yang , Yong Zhou

In this paper we will study the existence of fundamental solutions for the explicit and implicit backward time dependent Schodinger equation, via discrete Fourier transform and its symbol for the Laplace operator. In both cases we will…

Mathematical Physics · Physics 2007-11-26 P. Cerejeiras , N. Vieira

We consider the pointwise convergence problem for the solution of Schr\"odinger-type equations along directions determined by a given compact subset of the real line. This problem contains Carleson's problem as the most simple case and was…

Analysis of PDEs · Mathematics 2019-03-07 Shobu Shiraki

We demonstrate the existence of an open set of data which exhibits \textit{reversal} and \textit{recirculation} for the stationary Prandtl equations (data is taken in an appropriately defined product space due to the simultaneous forward…

Analysis of PDEs · Mathematics 2024-10-16 Sameer Iyer , Nader Masmoudi

We establish that the quadratic non-linear Schr\"odinger equation $$ iu_t + u_{xx} = u^2$$ where $u: \R \times \R \to \C$, is locally well-posed in $H^s(\R)$ when $s \geq -1$ and ill-posed when $s < -1$. Previous work of Kenig, Ponce and…

Analysis of PDEs · Mathematics 2007-10-29 Ioan Bejenaru , Terence Tao

We consider the Cauchy problem of fractional pseudo-parabolic equation on the whole space $R^n,n\geq 1$. Here, the fractional order $\alpha$ is related to the diffusion-type source term behaving as the usual diffusion term on the high…

Analysis of PDEs · Mathematics 2017-03-28 Lingyu Jin , Lang Li , Shaomei Fang

In this paper we study the following class of fractional relativistic Schr\"odinger equations: \begin{equation*} \left\{ \begin{array}{ll} (-\Delta+m^{2})^{s}u + V(\varepsilon x) u= f(u) &\mbox{ in } \mathbb{R}^{N}, \\ u\in…

Analysis of PDEs · Mathematics 2023-03-24 Vincenzo Ambrosio

We analyze the quantum dynamics of the fractional-time Jaynes-Cummings model using a recent unitary framework for the fractional-time Schr\"odinger equation. We examine how the fractional derivative order $\alpha$ influences non-classical…

Quantum Physics · Physics 2026-04-23 Thiago T. Tsutsui , Danilo Cius , Antonio S. M. de Castro , Fabiano M. Andrade

We study the large time behaviour of the Fisher-KPP equation $\partial$ t u = $\Delta$u + u -- u 2 in spatial dimension N , when the initial datum is compactly supported. We prove the existence of a Lipschitz function s of the unit sphere,…

Analysis of PDEs · Mathematics 2019-03-28 Jean-Michel Roquejoffre , Luca Rossi , Violaine Roussier-Michon

Main results and techniques of the fractional calculus of variations are surveyed. We consider variational problems containing Caputo derivatives and study them using both indirect and direct methods. In particular, we provide necessary…

Optimization and Control · Mathematics 2018-11-12 Ricardo Almeida , Delfim F. M. Torres
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