What is the definition of light-cone gauge? Is there any advantage for working in this gauge?
Are you referring to string theory in particular (if so you might want to post in the Beyond The Standard Model subforum)? If yes, you should look at the book by Zwiebach where it is explained in details. Basically, it's the gauge where light-cone coordinates are used for the coordinates of string. The advantage in that gauge is that it's a "physical gauge" in the sense that only physical degrees of freedome are present from the very beginning. It's a bit like quantizing QED with only transverse polarizations of the photon present as the degrees of freedom. The disadvantage (like in QED) is that the theory quantized in that gauge is not manifestly Lorentz invariant and one has to check this carefully.What is the definition of light-cone gauge? Is there any advantage for working in this gauge?