Currently, I am working as a postdoctoral researcher at Cardiff University, funded by an Erwin Schrödinger fellowship of the Austrian Science Fund (FWF). On this page you may find my publications, recent preprints (also available on arXiv) as well as a curriculum vitae.
Preprints
 The inverse spectral problem for indefinite strings, with A. Kostenko, ... — PDF
 Quadratic operator pencils associated with the conservative Camassa–Holm flow, with A. Kostenko, ... — PDF
 A coupling problem for entire functions and its application to the longtime asymptotics of integrable wave equations, with G. Teschl, ... — PDF
Publications
 Spectral asymptotics for canonical systems, with A. Kostenko and G. Teschl, J. Reine Angew. Math. (to appear) — PDF
 On spectral deformations and singular Weyl functions for onedimensional Dirac operators, with A. Beigl, A. Kostenko and G. Teschl, J. Math. Phys. 56 (2015), no. 1, 012102, 11 pp. — PDF
 Inverse spectral problems for Schrödingertype operators with distributional matrixvalued potentials, with F. Gesztesy, R. Nichols, A. L. Sakhnovich and G. Teschl, Differential Integral Equations 28 (2015), no. 56, 505–522 — PDF
 Onedimensional Schrödinger operators with δ'interactions on Cantortype sets, with A. Kostenko, M. Malamud and G. Teschl, J. Differential Equations 257 (2014), no. 2, 415–449 — PDF
 An inverse spectral problem for a star graph of Krein strings, J. Reine Angew. Math. (to appear) — PDF
 Inverse uniqueness results for onedimensional weighted Dirac operators, with A. Kostenko and G. Teschl, in Spectral theory and differential equations, 117–133, Amer. Math. Soc. Transl. Ser. 2, 233, Amer. Math. Soc., Providence, RI, 2014 — PDF
 Singular Weyl–Titchmarsh–Kodaira theory for onedimensional Dirac operators, with R. Brunnhuber, A. Kostenko and G. Teschl, Monatsh. Math. 174 (2014), no. 4, 515–547 — PDF
 An isospectral problem for global conservative multipeakon solutions of the Camassa–Holm equation, with A. Kostenko, Comm. Math. Phys. 329 (2014), no. 3, 893–918 — PDF
 Inverse spectral theory for Sturm–Liouville operators with distributional potentials, with F. Gesztesy, R. Nichols and G. Teschl, J. Lond. Math. Soc. (2) 88 (2013), no. 3, 801–828 — PDF
 Weyl–Titchmarsh theory for Sturm–Liouville operators with distributional potentials, with F. Gesztesy, R. Nichols and G. Teschl, Opuscula Math. 33 (2013), no. 3, 467–563 — PDF
 Supersymmetry and Schrödingertype operators with distributional matrixvalued potentials, with F. Gesztesy, R. Nichols and G. Teschl, J. Spectr. Theory 4 (2014), no. 4, 715–768 — PDF
 On the isospectral problem of the dispersionless Camassa–Holm equation, with G. Teschl, Adv. Math. 235 (2013), 469–495 — PDF
 Singular Weyl–Titchmarsh–Kodaira theory for Jacobi operators, with G. Teschl, Oper. Matrices 7 (2013), no. 3, 695–712 — PDF
 Two inverse spectral problems for a class of singular Krein strings, Int. Math. Res. Not. IMRN 2014, no. 13, 3692–3713 — PDF

Direct and inverse spectral theory of singular leftdefinite Sturm–Liouville operators,
J. Differential Equations 253 (2012), no. 2, 604–634
— PDF
» Extended version with more detailed proofs — PDF  Uniqueness results for onedimensional Schrödinger operators with purely discrete spectra, with G. Teschl, Trans. Amer. Math. Soc. 365 (2013), no. 7, 3923–3942 — PDF
 Sturm–Liouville operators on time scales, with G. Teschl, J. Difference Equ. Appl. 18 (2012), no. 11, 1875–1887 — PDF
 Inverse uniqueness results for Schrödinger operators using de Branges theory, Complex Anal. Oper. Theory 8 (2014), no. 1, 37–50 — PDF
 Sturm–Liouville operators with measurevalued coefficients, with G. Teschl, J. Anal. Math. 120 (2013), no. 1, 151–224 — PDF
 On the connection between the Hilger and Radon–Nikodym derivatives, with G. Teschl, J. Math. Anal. Appl. 385 (2012), no. 2, 1184–1189 — PDF
Theses
 On the isospectral problem of the Camassa–Holm equation, doctoral thesis, University of Vienna, 2011 — PDF
 Direkte und inverse Spektraltheorie von Sturm–Liouville Differentialoperatoren, diploma thesis (in german), Vienna University of Technology, 2009 — PDF
Contact Information
Jonathan Eckhardt School of Computer Science & Informatics Cardiff University, Queen's buildings 5 The Parade, Roath Cardiff CF24 3AA Wales, UK Email: EckhardtJ@cardiff.ac.uk 