Upon graduation, he stayed on at the University, became Sommerfeld’s assistant on April 1, 1911, and he completed his Habilitation on February 20, 1914, becoming a Privatdozent on April 4, 1914.
După absolvire, a rămas pe la Universitate, devenind asistentul Sommerfeld cu incepere din aprilie 1911, iar la 20 februarie 1914 a obținut abilitarea , devenind privatdocent la 4 aprilie 1914.