[3][4][2] During his tours through Europe, America and Asia, he played in orchestral concerts with conductors such as István Kertész, Georg Solti, Horst Stein and Günter Wand and in chamber music formations with performers such as Arthur Grumiaux, Nathan Milstein, János Starker, Henryk Szeryng and the Amadeus Quartet.
[5] His master students include Ulrich Windfuhr,[6] Udo Schneberger, Alfredo Perl,[7] Sung-Hee Kim-Wüst, Friedrich Höricke, Raymund Havenith, Ulrich Leyendecker,[8] Gereon Krahforst, Andreas Rothkopf, Florian Wiek,[9] Johannes Cernota and Franz-Josef Birk.
Ludwig was a freelancer for Schott-Verlag and Wiener Urtext Edition[1] and a member of several juries of international competitions such as Bolzano and Genève.
[16][17] Ludwig recorded piano music by Beethoven, Mozart, Brahms, Busoni, Schubert and Schumann, among others.
With the violinist Alois Kottmann, he recorded violin sonatas by Max Reger and Robert Schumann.