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arXiv 1208.5474math.NAcs.NA
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四阶量子扩散方程的熵稳定与熵耗散逼近

Entropy-stable and entropy-dissipative approximations of a fourth-order quantum diffusion equation

Vienna University of Technology(维也纳工业大学);Technical University of Berlin(柏林工业大学)

Mario Bukal, Etienne Emmrich, Ansgar Jüngel

AI总结:

针对描述量子半导体中电子输运的非线性四阶抛物型方程,分析了保持非负性、熵稳定且耗散修正熵泛函的BDF时间半离散格式,并证明了弱解存在性与二阶收敛性。

摘要:

分析了具有周期边界条件的非线性四阶抛物型方程(描述量子半导体中电子输运)的结构保持数值格式。首先,研究了时间上的两步向后微分公式(BDF)半离散化。该格式保持解的非负性,是熵稳定的,并耗散修正的熵泛函。证明了弱半离散解的存在性,并在特定情况下证明了其时间二阶收敛到连续解。证明采用了一个代数关系,该关系蕴含了两步BDF的G稳定性。其次,考虑了隐式欧拉和q步BDF离散变分导数方法。该方案利用了方程的变分结构,耗散了离散Fisher信息(或能量)。数值实验表明,离散(相对)熵和Fisher信息甚至指数快速衰减到零。

英文摘要:

Structure-preserving numerical schemes for a nonlinear parabolic fourth-order equation, modeling the electron transport in quantum semiconductors, with periodic boundary conditions are analyzed. First, a two-step backward differentiation formula (BDF) semi-discretization in time is investigated. The scheme preserves the nonnegativity of the solution, is entropy stable and dissipates a modified entropy functional. The existence of a weak semi-discrete solution and, in a particular case, its temporal second-order convergence to the continuous solution is proved. The proofs employ an algebraic relation which implies the G-stability of the two-step BDF. Second, an implicit Euler and q-step BDF discrete variational derivative method are considered. This scheme, which exploits the variational structure of the equation, dissipates the discrete Fisher information (or energy). Numerical experiments show that the discrete (relative) entropies and Fisher information decay even exponentially fast to zero.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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