PhD students can complete research stays of 6 months. In any case, a professor from Viadrina has to agree to supervise you. Please note the detailed academic offering of Viadrina as well as the relevant language and other requirements, which are outlined on the project website. In any case, please contact Viadrina’s HERMES Coordinator Julian Irlenkäuser first. He will answer your questions and put you in contact with the relevant Department.
More information on doing a PhD at Viadrina is available on the website of the Viadrina Center for Graduate Studies.