scholarly journals Regularity estimates for elliptic nonlocal operators

2020 ◽  
Vol 13 (2) ◽  
pp. 317-370 ◽  
Author(s):  
Bartłomiej Dyda ◽  
Moritz Kassmann
2020 ◽  
Vol 10 (1) ◽  
pp. 895-921
Author(s):  
Daniele Cassani ◽  
Luca Vilasi ◽  
Youjun Wang

Abstract In this paper we study a class of one-parameter family of elliptic equations which combines local and nonlocal operators, namely the Laplacian and the fractional Laplacian. We analyze spectral properties, establish the validity of the maximum principle, prove existence, nonexistence, symmetry and regularity results for weak solutions. The asymptotic behavior of weak solutions as the coupling parameter vanishes (which turns the problem into a purely nonlocal one) or goes to infinity (reducing the problem to the classical semilinear Laplace equation) is also investigated.


2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Ivan M. Burbano ◽  
T. Rick Perche ◽  
Bruno de S. L. Torres

Abstract Particle detectors are an ubiquitous tool for probing quantum fields in the context of relativistic quantum information (RQI). We formulate the Unruh-DeWitt (UDW) particle detector model in terms of the path integral formalism. The formulation is able to recover the results of the model in general globally hyperbolic spacetimes and for arbitrary detector trajectories. Integrating out the detector’s degrees of freedom yields a line defect that allows one to express the transition probability in terms of Feynman diagrams. Inspired by the light-matter interaction, we propose a gauge invariant detector model whose associated line defect is related to the derivative of a Wilson line. This is another instance where nonlocal operators in gauge theories can be interpreted as physical probes for quantum fields.


2016 ◽  
Vol 153 (1-2) ◽  
pp. 53-70 ◽  
Author(s):  
Alberto Farina ◽  
Enrico Valdinoci

2013 ◽  
Vol 444-445 ◽  
pp. 731-737
Author(s):  
Zhi Bo Hou ◽  
Li Mei Li

In this paper, by using an iteration procedure, regularity estimates of the linear semi-groups and a generalized existence theorem of global attractor, we prove that the liquid helium-4 system possesses a global attractor in space for all , which attracts any bounded set of in the-norm.


2012 ◽  
Vol 2012 ◽  
pp. 1-16
Author(s):  
Hong Luo

By using an iteration procedure, regularity estimates for the linear semigroups, and a classical existence theorem of global attractor, we prove that the reaction-diffusion equation possesses a global attractor in Sobolev spaceHkfor allk>0, which attracts any bounded subset ofHk(Ω) in theHk-norm.


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