Dr. Joannis Alexopoulos

Dr. Joannis Alexopoulos

  • Englerstraße 2
    76131 Karlsruhe

Welcome! I am a PostDoc at the Institute for Analysis in the working group for nonlinear PDEs and my position is funded by the CRC "Wave Phenomena". In particular, my resarch contributes to the projects A1, A14 und B3.

Research interests

Some keywords:

  • Nonlinear stability of periodic wave trains and variants
  • Nonlinear dynamics under nonlocalized data
  • Degenerate diffusion equations
  • Nonlinear Schrödinger equations
  • Diffusive and hyperbolic relaxation systems
Publications
  • J. Alexopoulos — L^\infty-regularity thresholds for a generalized Gross-Pitaevskii equation: dispersive blow-up vs. nonlinear stability (Preprint, 2026)
  • J. Alexopoulos —  Asymptotics for wild and large data in the nonconservative NLS (Preprint, 2026)
  • J. Alexopoulos  — Nonlinear stability of periodic wave trains against nonlocalized perturbations, PhD Thesis (2025), Karlsruhe Institute of Technology (DOI)
  • J. Alexopoulos and B. de Rijk —  Nonlinear dynamics of reaction-diffusion wave trains under large and fully nonlocalized modulations (Preprint, 2025).
  • J. Alexopoulos — Nonlinear dynamics of periodic Lugiato-Lefever waves against sums of co-periodic and localized perturbations, Phys. D: Nonlinear Phenom. 488 (2026) 135079 (DOI, Preprint (2025)). 
  • J. Alexopoulos — Uniformity in the Fourier inversion formula with applications to Laplace transforms, Arch. Math. 125, 413–432 (2025). (DOI, Preprint (2025)). 
  • J. Alexopoulos und B. de Rijk — Nonlinear stability of periodic wave trains in the FitzHugh-Nagumo system against fully nonlocalized perturbations, J. Differential Equations 457 (2026). (DOI, Preprint (2024)). 
A selection on posters and Presentations

Part of a presentation to Chapman-Enskog type expansions for hyperbolic relaxation systems

On the result on large phase modulations:

On the result to the Lugiato-Lefever equation:

On the result to the FitzHugh-Nagumo system: