You can always Google "top universities for physics" or some variation of that.
Usually though, when you're looking for a university for graduate school, it's important to be thinking about what particular sub-field you're interested in. General rankings, even ones that are subject-specific, are based on metrics that may or may not be important to you as a student. General opinions, are also of limited value when someone doesn't know you or your particular circumstances and interests. This is often why it's a good idea to talk about this with professors that you know and who know you.