I have recently defended my PhD (though not technically graduated as in not had a ceremony yet) and am applying for funding for my postdoc. I have a mentor for the postdoc and even though I am not funded/employed by the postdoc advisor yet (instead living off remaining scholarship funding from my PhD, which thankfully hasn't run out yet despite my successful defence), I am (as I am a theorist) already working on things related to my postdoc project, potentially even publish some results before properly moving to the new institution.
I do wonder now how I will add this time period to my CV eventually? There is a clear time stamp to the end of my PhD through the defence, but I am not a postdoc as in "awarded PhD and on a position". Do I disregard that and call myself a postdoc as I am working on my postdoc project? Do I leave a gap? Some third option?
[I doubt it would matter but my field for both postdoc and PhD is quantum theory (though the postdoc is not a continuation of the PhD project but a bit of a jump).]