Abstract
In this paper we study eigenfunctions and fundamental solutions for the three parameter fractional Laplace operator \(\Delta _+^{(\alpha , \beta , \gamma )}:= D_{x_0^+}^{1+\alpha } +D_{y_0^+}^{1+\beta } +D_{z_0^+}^{1+\gamma },\) where \((\alpha , \beta , \gamma ) \in \,]0,1]^3\), and the fractional derivatives \(D_{x_0^+}^{1+\alpha }, D_{y_0^+}^{1+\beta }, D_{z_0^+}^{1+\gamma }\) are in the Riemann–Liouville sense. Applying operational techniques via two-dimensional Laplace transform we describe a complete family of eigenfunctions and fundamental solutions of the operator \(\Delta _+^{(\alpha ,\beta ,\gamma )}\) in classes of functions admitting a summable fractional derivative. Making use of the Mittag–Leffler function, a symbolic operational form of the solutions is presented. From the obtained family of fundamental solutions we deduce a family of fundamental solutions of the fractional Dirac operator, which factorizes the fractional Laplace operator. We apply also the method of separation of variables to obtain eigenfunctions and fundamental solutions.
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Acknowledgments
The authors were supported by Portuguese funds through the CIDMA - Center for Research and Development in Mathematics and Applications, and the Portuguese Foundation for Science and Technology (“FCT–Fundação para a Ciência e a Tecnologia”), within project UID/MAT/ 0416/2013. N. Vieira was also supported by FCT via the FCT Researcher Program 2014 (Ref: IF/00271/2014).
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Communicated by Uwe Kaehler.
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Ferreira, M., Vieira, N. Eigenfunctions and Fundamental Solutions of the Fractional Laplace and Dirac Operators: The Riemann-Liouville Case. Complex Anal. Oper. Theory 10, 1081–1100 (2016). https://doi.org/10.1007/s11785-015-0529-9
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DOI: https://doi.org/10.1007/s11785-015-0529-9
Keywords
- Fractional partial differential equations
- Fractional Laplace and Dirac operators
- Riemann-Liouville derivatives and integrals of fractional order
- Eigenfunctions and fundamental solution
- Laplace transform
- Mittag-Leffler function