I have seen various questions regarding PhDs in the EU vs US, but none I've seen address this. The subject area is Maths/Physics.
From what I've seen, in the EU you do a Masters (I'm soon to be finishing) and then PhD. In general this might take 4-6 years total for both. In the US you apply for a PhD after finishing undergrad studies and it takes 5-6 years total. There are classes in the first two years or so which make it roughly comparable overall to Europe.
My question: Is it possible to do a PhD in the US after completing a MSc in Europe, without have to go through the class component in the US? In other words, can one go straight to research?