The state one's hair assumes after spending copious amounts of time attempting and ultimately failing to solve a difficult physics problem. It occurs when you run your hand through your hair in frustration of being unable to solve the problem.
I was in the library all night doing physics, you should have seen my physics hair dude.
The Phenomenon of the fringe being lifted to great heights without the aid of gel caused by having been sitting with one's head resting on one's non-writing hand for the extended time required to complete Physics problems.
*Upon running into a Physics room-mate in the kitchen at 2am exhibiting the symptoms:
"Wow, dude. Nice Physics hair."