MESA LAB On tempered and substantial fractional calculus YangQuan Chen Collaborators: Jianxiong Cao, Changpin Li School of Engineering, University of California, Merced Department of Mathematics, Shanghai University E: yangquan.

MESA LAB Outline Preliminaries of fractional calculus Tempered and substantial fractional operators Numerical solution of a tempered diffusion equation Conclusion

MESA LAB Preliminaries Calculus=integration+differentiation Fractional Calculus= fractional integration+ fractional differentiation Fractional integral: Mainly one: Riemann-Liouville integral Fractional derivatives More than 6: not mutually equivalent RL and Caputo derivatives are mostly used

MESA LAB Preliminaries Left Riemann-Liouville integral Right Riemann-Liouville Integral Left Riemann-Liouville fractional derivative Right Riemann-liouville Fractional derivative

MESA LAB Left Caputo fractional derivative Right Caputo fractional derivative Riesz fractional derivative Riesz-Caputo fractional derivative where

MESA LAB Tempered and substantial operator Let be piecewise continuous on,and integrable on any subinterval of, 1)The left Riemann-Liouville tempered fractional integral is 2)The right Riemann-Liouville tempered fractional integral Slide-6/1024

MESA LAB Slide-7/1024 Suppose that be times continuously differentiable on, and times derivatives be integrable on any subinterval of, then the left and right Riemann-Liouville tempered derivative are defined ( Phys. Rev. E 76, , 2007 ) and

MESA LAB Slide-8/1024 Remark I: From the above definitions, we can see if then they reduce to left and right Riemann-Liouville Fractional derivatives. Remark II: The variants of the left and right Riemann-Liouville tempered fractional derivatives (Boris Baeumer, JCAM, 2010)

MESA LAB Slide-9/1024 (Phys. Rev. Lett. 96, , 2006) Substantial fractional operators Let be piecewise continuous on, and integrable on any subinterval of, then the substantial fractional integral is defined by And the substantial derivative is defined as where

MESA LAB Slide-10/1024 Theorem: If the parameter is a positive constant, the tempered and substantial operators are equivalent. See our paper for the details of proof. Recently, tempered fractional calculus is introduced in Mark M. Meerschaert et al. JCP(2014).

MESA LAB Numerical computation of a tempered diffusion equation We consider the following tempered diffusion equation where Slide-11/1024

MESA LAB Slide-12/1024 The exact solution of above problem is We use finite difference method and shifted Grunwald method to numerically solve it, we choose different value Of parameter, and compare the results with its exact solution

MESA LAB Slide-13/1024

MESA LAB Slide-14/1024

MESA LAB Slide-15/1024

MESA LAB Slide-16/1024  From the figures, we can see that the numerical solution are in good accordance with exact solutions.  It is easily shown that the peak of the solutions of tempered diffusion equation becomes more and more smooth as exponential factor λ increases.

MESA LAB Conclusion Tempered and substantial fractional calculus are the generalizations of fractional calculus. The two fractional operators are equivalent, although they are introdued from different physical backgrounds. Tempered fractional operators are the best tool for truncated exponential power law description

MESA LAB Thanks for your attention