I am struggling to decide which Physics PhD program to attend before April 15th. Currently I am getting stuck in a tricky situation, I'd greatly appreciate for anyone who offers me advice!


I am accepted into two physics PhD programs. One is very good with strong research (highly prestigious university with strong reputation in physics), the other one also has strong research but seems to be weaker than the 1st program I mentioned (smaller department, less research topics and connections). BUT I was only accepted into the 1st program because a professor whom I contacted previously were willing to let me join his lab. His research aligns pretty well with my current research, HOWEVER I don't actually feel passionate about my current research field and I'm now seriously considering to switch to other physics research field. I've also talked with a few PhD students that were working with him and they didn't seem to quite enjoy their research there...However, I feel switching advisor is really unethical since it was him that decided to let the program accept me (I mean this sincerely, the process was a bit complicated but that's basically what happened). And this PhD program has very limited rotation for students. Typically student starts serious research with an advisor during the spring semester of first year, so if I join this program I guess I would basically be working in a research field that I am not passionate about.
For the 2nd program, since I didn't contact any professor there previously I might have more freedom to choose advisors. Student there have at least 1.5 years to choose research topic and advisors. I also found a few excellent professors whose research I feel very interesting, and a few PhD students I've talked with all seem to enjoy their life at the school. (Bonus point: this school is located in the downtown of a big metropolis and doesn't require a car to get around! Big bonus for international students like me!)
So my question is: should I join a very strong program with very limited freedom to choose research topics and advisors, or join a weaker program with more freedom to choose research topics and advisors?
Thank you so much guys! I'd welcome any advices no matter what. Even if you cannot answer the question, your advice and experience still offer me lots of insights! Thanks!

