# Quantising Fields

1. Jun 3, 2005

### jack47

I'm taking a QFT course and there is something that is bugging me. When we write out the equations in terms of generalised coordinates (q and p like in Lagrangian mechanics), it is always then taken as obvious that q and p satisfy the position momentum commutation relation. They arn't position and momentum so is there any prior justification for using the given commutator? (apart from the fact that when we do use it we get a nice working theory)

2. Jun 3, 2005

### dextercioby

One quantizes the classical field theory in which the graded fundamental Poisson brackets at equal times will become graded Lie brackets at equal times.

So they don't really come from nowhere.

Daniel.