Force state briefly to give up (6)
I believe the answer is:
forego
'give up' is the definition.
'force state briefly' is the wordplay.
'force' becomes 'f' (symbol used in Physics e.g. f=ma).
'state' becomes 'or'.
'briefly' becomes 'ego' (I can't explain this - if you can you should believe this answer much more).
'f'+'or'+'ego'='FOREGO'
'to' is the link.
(Other definitions for forego that I've seen before include "Go without or precede" , "Go without, give up" , "Go without (desirable thing)" , "Take precedence" , "Surrender" .)