I had a six month period between two jobs (I already had the offer), in which I was not affiliated with any institution. The reason was an urgent surgical operation.
In these months I still did (without a contract ) research with my alma mater university, together with my PhD advisor, and we published material.
How do I indicate this period on my CV? Would the term ‘’external collaborator’’ be appropriate?
I would be fine seeing that. "Independent Researcher" is also pretty common. However, I might have a question about it in an interview. Be prepared to give an honest and convincing reason.
If you had accepted the offer it might be possible to claim affiliation with the new employer and add "medical leave". That would depend on whether all of the paper work was in place and the employer agreed to the delay. But it would take deeper analysis than can be made with the information available here.
