The openness training encourages you to explore other areas of physics but also other sciences, not necessarily related (i.e. training in mathematics is acceptable, but so is sociology or philosophy). These courses can also expose you to the history of science, scientific media, relations between science and society, etc.

This list is not exhaustive, and you should first check whether any given program is eligible by contacting the representative for your enrolling institution on the Executive Board of the ED.

 

Some useful links: