arXiv subjects

Zeinab Karaki

Publications and source records attributed to Zeinab Karaki.

4 recordsLinked to original sources

arXiv2022

Study of the Kramers-Fokker-Planck quadratic operator with a constant magnetic field

We study the quadratic Kramers-Fokker-Planck operator with a constant magnetic field and with a quadratic potential. We describe the exact expression of the norm of the semi-group associated to the operator near the equilibrium. At this level, explicit and accurate estimates of this norm are shown in small and long times as well as uniform-in-time estimates when the magnetic parameter $b$ tends to infinity.

math.AP↗

arXiv2020

Maximal estimates for the Kramers-Fokker-Planck operator with electromagnetic field

In continuation of a former work by the first author with F. Nier (2009) and of a more recent work by the second author on the torus (2019), we consider the Kramers-Fokker-Planck operator (KFP) with an external electromagnetic field on R d. We show a maximal type estimate on this operator using a nilpotent approach for vector field polynomial operators and induced representations of a nilpotent graded Lie algebra. This estimate leads to an optimal characterization of the domain of the closure of the KFP operator and a criterion for the compactness of the resolvent.

math.AP↗

arXiv2019

Maximal estimates for the Fokker-Planck operator with strong magnetic field

We consider the Vlasov-Fokker-Planck operator with a strong external magnetic field. We show a maximal type estimate on this operator using a nilpotent approach on vector field polynomial operators and including the notion of representation on a Lie algebra. This estimate makes it possible to give a better characterization of the domain of the closure of the considered operator.

math.SP↗

arXiv2019

Trend to the equilibrium for the Fokker-Planck system with a strong external magnetic field

We consider the Fokker-Planck equation with a strong external magnetic field. Global-in-time solutions are built near the Maxwellian, the global equilibrium state for the system. Moreover, we prove the convergence to equilibrium at exponential rate. The results are first obtained on spaces with an exponential weight. Then they are extended to larger functional spaces, like the Lebesgue space and the Sobolev space with polynomial weight, by the method of factorization and enlargement of the functional space developed in [Gualdani, Mischler, Mouhot, 2017].

math.AP↗