Smallest Advantage Possible in Chess?

This is a thought experiment that I find amusing so I thought I would share it. I think about this a lot.

What is the smallest possible advantage in chess?

A pawn? ...maybe

An extra square of space?

A second on the clock?...maybe..but there are times that this is decisive which would make it a big advantage.

As with everything in the mystery of chess, there probably is no objective answer that is always true...doesn't diminish the thought exercise though. (At least not in my opinion)

I like thinking about tiny advantages and the relationships they have with one another.  Are they always additive?  Or can they compound multiplicatively somehow?

Anyway, I'd love to hear some thoughts.

Prob'ly at the beginning, when no moves are made and clock jumps from 2:00:00 to 1:59:59. 

the smallest advantage is an extra knight in a K v KN endgame.

The smallest advantage is a half espresso.

Bulgarian earbud (an advantage so small it fits in your ear) only kidding

lol