That will be a short article, mainly because of two things. First, some methods are beyond my knowledge, involving electronics or hardware manipulation. Second, such methods are not efficient compare to higher level ones, and so rarely used.
The mere concept of a physical attack implies that you have a direct physical access to your target, giving you the ability to modify it as you wish.
This is an ideal situation for an attacker, not quite common. And in that case, there is nothing much to be done on the defensive side.