Prof. Dr. Sören Bartels

Address:	Institut für Numerische Simulation Wegelerstr. 6 53115 Bonn Germany
Office:	We6 6.002
Phone:	+49 228 732058
E-Mail:	bartelsins.uni-bonn.de

Research Projects

	DFG Research Center MATHEON Project C16: Simulation of phase field models and geometric evolution problems
	Adaptive approximation of elliptic partial differential equations and variational inequalities
	Phase transitions in crystalline solids - numerical analysis of nonconvex variational problems

Teaching

WS 2009/2010:
Lecture Einführung in die Numerische Mathematik, module V2E1
WS 2009/2010:
Seminar Hauptseminar Numerik, module S2E1
WS 2009/2010:
Laboratory Übungen zu Einführung in die Numerische Mathematik, module V2E1
SS 2009:
Lecture Master's Thesis Seminar, module S5G1
SS 2009:
Seminar Numerical Analysis, module S5E1
WS 2008/2009:
Lecture V4E1 - Numerical Algorithms - Wissenschaftliches Rechnen III
WS 2008/2009:
Seminar S4E2 - Graduate Seminar on Numerical Simulation - Ausgewählte Kapitel in der adaptiven Diskretisierung partieller Differentialgleichungen
WS 2008/2009:
Laboratory V4E1 - Exercises to Numerical Algorithms - Wissenschaftliches Rechnen III
SS 2008:
Lecture Numerik einiger nichtlinearer partieller Differentialgleichungen, module V5E2
SS 2008:
Seminar Lösung linearer und nicht-linearer Probleme mit numerischen Verfahren, module S1G1
SS 2008:
Seminar Numerik von Optimierungsaufgaben, module S2E1
WS 2007/2008:
Lecture Gemischte Finite Elemente Methoden

Publications

Preprints:

[1] S. Bartels and R. Müller. Optimal and robust a posteriori error estimates in L(L²) for the approximation of Allen-Cahn equations past singularities. 2009.
[ bib | .pdf 1 ]

[2] S. Bartels, R. Müller, and C. Ortner. Robust a priori and a posteriori error analysis for the approximation of Allen-Cahn and Ginzburg-Landau equations past topological changes. 2009.
[ bib | .pdf 1 ]

[3] S. Bartels and T. Roubíček. Thermo-visco-elasticity with rate-independent plasticity in isotropic materials undergoing thermal expansion. 2009.
[ bib | .pdf 1 ]

[4] S. Bartels. Numerical analysis of a finite element scheme for the approximation of harmonic maps into surfaces. 2008.
[ bib | .pdf 1 ]

[5] S. Bartels. Semi-implicit approximation of wave maps into smooth or convex surfaces. 2008.
[ bib | .pdf 1 ]

[6] S. Bartels. Combination of global and local approximation schemes for harmonic maps. J. Comp. Math. (accepted), 2008.
[ bib ]

[7] S. Bartels, G. Dolzmann, and R. H. Nochetto. A finite element scheme for the evolution of orientational order in fluid membranes. 2008.
[ bib | .pdf 1 ]

[8] S. Bartels, M. Jensen, and R. Müller. Discontinuous Galerkin finite element convergence for incompressible miscible displacement problems of low regularity. 2008.
[ bib | .pdf 1 ]

[9] S. Bartels and R. Müller. Error controlled local resolution of evolving interfaces for generalized Cahn-Hilliard dynamics. 2008.
[ bib | .pdf 1 ]

[10] S. Bartels, C. Lubich, and A. Prohl. Convergent discretization of heat and wave map flows to spheres using approximate discrete lagrange multipliers. Math. Comp. (accepted), 2007.
[ bib | .pdf 1 ]

Articles:

[1] L. Baňas, S. Bartels, and A. Prohl. A convergent implicit finite element discretization of the Maxwell-Landau-Lifshitz-Gilbert equation. SIAM J. Numer. Anal., 46(3):1399-1422, 2008.
[ bib | .pdf 1 ]

[2] S. Bartels and C. Carstensen. A convergent adaptive finite element method for an optimal design problem. Numer. Math., 108(3):359-385, 2008.
[ bib | .pdf 1 ]

[3] S. Bartels, J. Ko, and A. Prohl. Numerical analysis of an explicit approximation scheme for the Landau-Lifshitz-Gilbert equation. Math. Comp., 77(262):773-788, 2008.
[ bib | .pdf 1 ]

[4] S. Bartels and A. Prohl. Convergence of an implicit, constraint preserving finite element discretization of p-harmonic heat flow into spheres. Numer. Math., 109(4):489-507, 2008.
[ bib | .pdf 1 ]

[5] S. Bartels and T. Roubíček. Thermoviscoplasticity at small strains. ZAMM Z. Angew. Math. Mech., 88(9):735-754, 2008.
[ bib | .pdf 1 ]

[6] S. Bartels, X. Feng, and A. Prohl. Finite element approximations of wave maps into spheres. SIAM J. Numer. Anal., 46(1):61-87, 2007/08.
[ bib | .pdf 1 ]

[7] J. W. Barrett, S. Bartels, X. Feng, and A. Prohl. A convergent and constraint-preserving finite element method for the p-harmonic flow into spheres. SIAM J. Numer. Anal., 45(3):905-927 (electronic), 2007.
[ bib | .pdf 1 ]

[8] S. Bartels and A. Prohl. Stable discretization of scalar and constrained vectorial Perona-Malik equation. Interfaces Free Bound., 9(4):431-453, 2007.
[ bib | .pdf 1 ]

[9] S. Bartels and A. Prohl. Constraint preserving implicit finite element discretization of harmonic map flow into spheres. Math. Comp., 76(260):1847-1859 (electronic), 2007.
[ bib | .pdf 1 ]

[10] S. Bartels, C. Carstensen, S. Conti, K. Hackl, U. Hoppe, and A. Orlando. Relaxation and the computation of effective energies and microstructures in solid mechanics. In Analysis, modeling and simulation of multiscale problems, pages 197-224. Springer, Berlin, 2006.
[ bib | .pdf 1 ]

[11] S. Bartels, C. Carstensen, and A. Hecht. P2Q2Iso2D=2D isoparametric FEM in Matlab. J. Comput. Appl. Math., 192(2):219-250, 2006.
[ bib | .pdf 1 ]

[12] S. Bartels and A. Prohl. Convergence of an implicit finite element method for the Landau-Lifshitz-Gilbert equation. SIAM J. Numer. Anal., 44(4):1405-1419 (electronic), 2006.
[ bib | .pdf 1 ]

[13] S. Bartels. Robust a priori error analysis for the approximation of degree-one Ginzburg-Landau vortices. M2AN Math. Model. Numer. Anal., 39(5):863-882, 2005.
[ bib | .pdf 1 ]

[14] S. Bartels. Reliable and efficient approximation of polyconvex envelopes. SIAM J. Numer. Anal., 43(1):363-385 (electronic), 2005.
[ bib | .pdf 1 ]

[15] S. Bartels. Stability and convergence of finite-element approximation schemes for harmonic maps. SIAM J. Numer. Anal., 43(1):220-238 (electronic), 2005.
[ bib | .pdf 1 ]

[16] S. Bartels. A posteriori error analysis for time-dependent Ginzburg-Landau type equations. Numer. Math., 99(4):557-583, 2005.
[ bib | .pdf 1 ]

[17] S. Bartels. Linear convergence in the approximation of rank-one convex envelopes. M2AN Math. Model. Numer. Anal., 38(5):811-820, 2004.
[ bib | .pdf 1 ]

[18] S. Bartels. Adaptive approximation of Young measure solutions in scalar nonconvex variational problems. SIAM J. Numer. Anal., 42(2):505-530 (electronic), 2004.
[ bib | .pdf 1 ]

[19] S. Bartels and C. Carstensen. Averaging techniques yield reliable a posteriori finite element error control for obstacle problems. Numer. Math., 99(2):225-249, 2004.
[ bib | .pdf 1 ]

[20] S. Bartels, C. Carstensen, K. Hackl, and U. Hoppe. Effective relaxation for microstructure simulations: algorithms and applications. Comput. Methods Appl. Mech. Engrg., 193(48-51):5143-5175, 2004.
[ bib | .pdf 1 ]

[21] S. Bartels, C. Carstensen, and G. Dolzmann. Inhomogeneous Dirichlet conditions in a priori and a posteriori finite element error analysis. Numer. Math., 99(1):1-24, 2004.
[ bib | .pdf 1 ]

[22] S. Bartels, C. Carstensen, P. Plecháč, and A. Prohl. Convergence for stabilisation of degenerately convex minimisation problems. Interfaces Free Bound., 6(2):253-269, 2004.
[ bib | .pdf 1 ]

[23] S. Bartels and A. Prohl. Multiscale resolution in the computation of crystalline microstructure. Numer. Math., 96(4):641-660, 2004.
[ bib | .pdf 1 ]

[24] S. Bartels and T. Roubíček. Linear-programming approach to nonconvex variational problems. Numer. Math., 99(2):251-287, 2004.
[ bib | .pdf 1 ]

[25] S. Bartels and C. Carstensen. Each averaging technique yields reliable a posteriori error control in FEM on unstructured grids. II. Higher order FEM. Math. Comp., 71(239):971-994 (electronic), 2002.
[ bib | .pdf 1 ]

[26] C. Carstensen and S. Bartels. Each averaging technique yields reliable a posteriori error control in FEM on unstructured grids. I. Low order conforming, nonconforming, and mixed FEM. Math. Comp., 71(239):945-969 (electronic), 2002.
[ bib | .pdf 1 ]

[27] C. Carstensen, S. Bartels, and S. Jansche. A posteriori error estimates for nonconforming finite element methods. Numer. Math., 92(2):233-256, 2002.
[ bib | .pdf 1 ]

[28] C. Carstensen, S. Bartels, and R. Klose. An experimental survey of a posteriori Courant finite element error control for the Poisson equation. Adv. Comput. Math., 15(1-4):79-106 (2002), 2001. A posteriori error estimation and adaptive computational methods.
[ bib | .pdf 1 ]

[29] S. Bartels, C. Carstensen, and P. Plecháč. Finite element computation of macroscopic quantities in nonconvex minimisation problems and applications in materials science. In Multifield problems, pages 69-79. Springer, Berlin, 2000.
[ bib | .pdf 1 ]

Proceedings:

[1] S. Bartels and R. Müller. Robust error estimates for adaptive phase field simulations. Proc. Appl. Math. Mech, 7(1):10983 - 10984, 2009.
[ bib | .pdf 1 ]

[2] S. Bartels. Approximation of harmonic maps and wave maps. Oberwolfach Reports, 5(3):2037-2038, 2008. Oberwolfach Workshop on Nonstandard Finite Element Methods.
[ bib | .pdf 1 ]

[3] S. Bartels and R. Müller. Robust a-posteriori error control of Cahn-Hilliard type equations with elasticity. Proc. Appl. Math. Mech, 7(1):1023305 - 1023306, 2008.
[ bib | .pdf 1 ]

[4] S. Bartels. Constraint preserving, inexact solution of implicit discretizations of Landau-Lifshitz-Gilbert equations and consequences for convergence. Proc. Appl. Math. Mech, 6(1):19-22, 2006.
[ bib | .pdf 1 ]

[5] S. Bartels. Error estimates for the adaptive computation of a scalar three well problem. Proc. Appl. Math. Mech, 1(1):502-503, 2002.
[ bib | .pdf 1 ]

Theses:

[1] S. Bartels. Finite element approximation of harmonic maps betweeen surfaces. Habilitation thesis, Humboldt Universität zu Berlin, Berlin, Germany, 2009.
[ bib | .pdf 1 ]

[2] S. Bartels. Numerical analysis of some nonconvex variational problems. Ph.d. thesis, Christian-Albrechts Universität zu Kiel, Kiel, Germany, 2001.
[ bib | http | .pdf 1 ]

[3] S. Bartels. Theorie und Numerik retardierter Integralgleichungen elektromagnetischer Streufelder. Diploma thesis (unpublished), Christian-Albrechts Universität zu Kiel, Kiel, Germany, 1999.
[ bib | .pdf 1 ]

[4] S. Bartels. Numerical analysis of retarded potential integral equations of electromagnetism. M.sc. thesis (unpublished), Heriott-Watt University Edinburgh, Edinburgh, UK, 1998.
[ bib | .pdf 1 ]

[1]	S. Bartels and R. Müller. Optimal and robust a posteriori error estimates in L(L²) for the approximation of Allen-Cahn equations past singularities. 2009. [ bib \| .pdf 1 ]
[2]	S. Bartels, R. Müller, and C. Ortner. Robust a priori and a posteriori error analysis for the approximation of Allen-Cahn and Ginzburg-Landau equations past topological changes. 2009. [ bib \| .pdf 1 ]
[3]	S. Bartels and T. Roubíček. Thermo-visco-elasticity with rate-independent plasticity in isotropic materials undergoing thermal expansion. 2009. [ bib \| .pdf 1 ]
[4]	S. Bartels. Numerical analysis of a finite element scheme for the approximation of harmonic maps into surfaces. 2008. [ bib \| .pdf 1 ]
[5]	S. Bartels. Semi-implicit approximation of wave maps into smooth or convex surfaces. 2008. [ bib \| .pdf 1 ]
[6]	S. Bartels. Combination of global and local approximation schemes for harmonic maps. J. Comp. Math. (accepted), 2008. [ bib ]
[7]	S. Bartels, G. Dolzmann, and R. H. Nochetto. A finite element scheme for the evolution of orientational order in fluid membranes. 2008. [ bib \| .pdf 1 ]
[8]	S. Bartels, M. Jensen, and R. Müller. Discontinuous Galerkin finite element convergence for incompressible miscible displacement problems of low regularity. 2008. [ bib \| .pdf 1 ]
[9]	S. Bartels and R. Müller. Error controlled local resolution of evolving interfaces for generalized Cahn-Hilliard dynamics. 2008. [ bib \| .pdf 1 ]
[10]	S. Bartels, C. Lubich, and A. Prohl. Convergent discretization of heat and wave map flows to spheres using approximate discrete lagrange multipliers. Math. Comp. (accepted), 2007. [ bib \| .pdf 1 ]

[1]	L. Baňas, S. Bartels, and A. Prohl. A convergent implicit finite element discretization of the Maxwell-Landau-Lifshitz-Gilbert equation. SIAM J. Numer. Anal., 46(3):1399-1422, 2008. [ bib \| .pdf 1 ]
[2]	S. Bartels and C. Carstensen. A convergent adaptive finite element method for an optimal design problem. Numer. Math., 108(3):359-385, 2008. [ bib \| .pdf 1 ]
[3]	S. Bartels, J. Ko, and A. Prohl. Numerical analysis of an explicit approximation scheme for the Landau-Lifshitz-Gilbert equation. Math. Comp., 77(262):773-788, 2008. [ bib \| .pdf 1 ]
[4]	S. Bartels and A. Prohl. Convergence of an implicit, constraint preserving finite element discretization of p-harmonic heat flow into spheres. Numer. Math., 109(4):489-507, 2008. [ bib \| .pdf 1 ]
[5]	S. Bartels and T. Roubíček. Thermoviscoplasticity at small strains. ZAMM Z. Angew. Math. Mech., 88(9):735-754, 2008. [ bib \| .pdf 1 ]
[6]	S. Bartels, X. Feng, and A. Prohl. Finite element approximations of wave maps into spheres. SIAM J. Numer. Anal., 46(1):61-87, 2007/08. [ bib \| .pdf 1 ]
[7]	J. W. Barrett, S. Bartels, X. Feng, and A. Prohl. A convergent and constraint-preserving finite element method for the p-harmonic flow into spheres. SIAM J. Numer. Anal., 45(3):905-927 (electronic), 2007. [ bib \| .pdf 1 ]
[8]	S. Bartels and A. Prohl. Stable discretization of scalar and constrained vectorial Perona-Malik equation. Interfaces Free Bound., 9(4):431-453, 2007. [ bib \| .pdf 1 ]
[9]	S. Bartels and A. Prohl. Constraint preserving implicit finite element discretization of harmonic map flow into spheres. Math. Comp., 76(260):1847-1859 (electronic), 2007. [ bib \| .pdf 1 ]
[10]	S. Bartels, C. Carstensen, S. Conti, K. Hackl, U. Hoppe, and A. Orlando. Relaxation and the computation of effective energies and microstructures in solid mechanics. In Analysis, modeling and simulation of multiscale problems, pages 197-224. Springer, Berlin, 2006. [ bib \| .pdf 1 ]
[11]	S. Bartels, C. Carstensen, and A. Hecht. P2Q2Iso2D=2D isoparametric FEM in Matlab. J. Comput. Appl. Math., 192(2):219-250, 2006. [ bib \| .pdf 1 ]
[12]	S. Bartels and A. Prohl. Convergence of an implicit finite element method for the Landau-Lifshitz-Gilbert equation. SIAM J. Numer. Anal., 44(4):1405-1419 (electronic), 2006. [ bib \| .pdf 1 ]
[13]	S. Bartels. Robust a priori error analysis for the approximation of degree-one Ginzburg-Landau vortices. M2AN Math. Model. Numer. Anal., 39(5):863-882, 2005. [ bib \| .pdf 1 ]
[14]	S. Bartels. Reliable and efficient approximation of polyconvex envelopes. SIAM J. Numer. Anal., 43(1):363-385 (electronic), 2005. [ bib \| .pdf 1 ]
[15]	S. Bartels. Stability and convergence of finite-element approximation schemes for harmonic maps. SIAM J. Numer. Anal., 43(1):220-238 (electronic), 2005. [ bib \| .pdf 1 ]
[16]	S. Bartels. A posteriori error analysis for time-dependent Ginzburg-Landau type equations. Numer. Math., 99(4):557-583, 2005. [ bib \| .pdf 1 ]
[17]	S. Bartels. Linear convergence in the approximation of rank-one convex envelopes. M2AN Math. Model. Numer. Anal., 38(5):811-820, 2004. [ bib \| .pdf 1 ]
[18]	S. Bartels. Adaptive approximation of Young measure solutions in scalar nonconvex variational problems. SIAM J. Numer. Anal., 42(2):505-530 (electronic), 2004. [ bib \| .pdf 1 ]
[19]	S. Bartels and C. Carstensen. Averaging techniques yield reliable a posteriori finite element error control for obstacle problems. Numer. Math., 99(2):225-249, 2004. [ bib \| .pdf 1 ]
[20]	S. Bartels, C. Carstensen, K. Hackl, and U. Hoppe. Effective relaxation for microstructure simulations: algorithms and applications. Comput. Methods Appl. Mech. Engrg., 193(48-51):5143-5175, 2004. [ bib \| .pdf 1 ]
[21]	S. Bartels, C. Carstensen, and G. Dolzmann. Inhomogeneous Dirichlet conditions in a priori and a posteriori finite element error analysis. Numer. Math., 99(1):1-24, 2004. [ bib \| .pdf 1 ]
[22]	S. Bartels, C. Carstensen, P. Plecháč, and A. Prohl. Convergence for stabilisation of degenerately convex minimisation problems. Interfaces Free Bound., 6(2):253-269, 2004. [ bib \| .pdf 1 ]
[23]	S. Bartels and A. Prohl. Multiscale resolution in the computation of crystalline microstructure. Numer. Math., 96(4):641-660, 2004. [ bib \| .pdf 1 ]
[24]	S. Bartels and T. Roubíček. Linear-programming approach to nonconvex variational problems. Numer. Math., 99(2):251-287, 2004. [ bib \| .pdf 1 ]
[25]	S. Bartels and C. Carstensen. Each averaging technique yields reliable a posteriori error control in FEM on unstructured grids. II. Higher order FEM. Math. Comp., 71(239):971-994 (electronic), 2002. [ bib \| .pdf 1 ]
[26]	C. Carstensen and S. Bartels. Each averaging technique yields reliable a posteriori error control in FEM on unstructured grids. I. Low order conforming, nonconforming, and mixed FEM. Math. Comp., 71(239):945-969 (electronic), 2002. [ bib \| .pdf 1 ]
[27]	C. Carstensen, S. Bartels, and S. Jansche. A posteriori error estimates for nonconforming finite element methods. Numer. Math., 92(2):233-256, 2002. [ bib \| .pdf 1 ]
[28]	C. Carstensen, S. Bartels, and R. Klose. An experimental survey of a posteriori Courant finite element error control for the Poisson equation. Adv. Comput. Math., 15(1-4):79-106 (2002), 2001. A posteriori error estimation and adaptive computational methods. [ bib \| .pdf 1 ]
[29]	S. Bartels, C. Carstensen, and P. Plecháč. Finite element computation of macroscopic quantities in nonconvex minimisation problems and applications in materials science. In Multifield problems, pages 69-79. Springer, Berlin, 2000. [ bib \| .pdf 1 ]

[1]	S. Bartels and R. Müller. Robust error estimates for adaptive phase field simulations. Proc. Appl. Math. Mech, 7(1):10983 - 10984, 2009. [ bib \| .pdf 1 ]
[2]	S. Bartels. Approximation of harmonic maps and wave maps. Oberwolfach Reports, 5(3):2037-2038, 2008. Oberwolfach Workshop on Nonstandard Finite Element Methods. [ bib \| .pdf 1 ]
[3]	S. Bartels and R. Müller. Robust a-posteriori error control of Cahn-Hilliard type equations with elasticity. Proc. Appl. Math. Mech, 7(1):1023305 - 1023306, 2008. [ bib \| .pdf 1 ]
[4]	S. Bartels. Constraint preserving, inexact solution of implicit discretizations of Landau-Lifshitz-Gilbert equations and consequences for convergence. Proc. Appl. Math. Mech, 6(1):19-22, 2006. [ bib \| .pdf 1 ]
[5]	S. Bartels. Error estimates for the adaptive computation of a scalar three well problem. Proc. Appl. Math. Mech, 1(1):502-503, 2002. [ bib \| .pdf 1 ]

[1]	S. Bartels. Finite element approximation of harmonic maps betweeen surfaces. Habilitation thesis, Humboldt Universität zu Berlin, Berlin, Germany, 2009. [ bib \| .pdf 1 ]
[2]	S. Bartels. Numerical analysis of some nonconvex variational problems. Ph.d. thesis, Christian-Albrechts Universität zu Kiel, Kiel, Germany, 2001. [ bib \| http \| .pdf 1 ]
[3]	S. Bartels. Theorie und Numerik retardierter Integralgleichungen elektromagnetischer Streufelder. Diploma thesis (unpublished), Christian-Albrechts Universität zu Kiel, Kiel, Germany, 1999. [ bib \| .pdf 1 ]
[4]	S. Bartels. Numerical analysis of retarded potential integral equations of electromagnetism. M.sc. thesis (unpublished), Heriott-Watt University Edinburgh, Edinburgh, UK, 1998. [ bib \| .pdf 1 ]