As PhysicsOverflow is not part of the Stack Exchange network, it is not possible to diractly link accounts here to accounts on SE sites. However members who would like some, a whole bunch, or all of their for PhysicsOverflow on topic SE posts (questions and answers) to be imported, can request this on the Import votes thread, which is accessible from a link in the top menu bar.
Users who have problems with regaining their SE or TP.SE accounts and/or are worried about giving their password away, are adviced to report this to
admin@physicsoverflow.org
We will then reset the already existing account for you and send you the new login data (user name, email, and a newly created password) per mail. The password (and email) can afterwards be changed under "My Account" at the top of the page.