Transitioning from math to physics in gradschool

[prince123]

Dear All,

Currently I am enrolled in a major American research university in the mathematics PhD program. I just finished my first year. I also hold a Bachelors and a Masters degree in statistics. However I have always want to do research in physics. So at this point I am very seriously considering to shift to a physics program.

I would like to have advice on the following topics:
1. Which universities I should apply to? I do not have much physics background per se(I have taken undergraduate courses on CM, QM, EM and thermodynamics). However my math background is quite good and I have a number of advanced graduate level math courses under my belt. I also have quite high grades throughout my academic career. So what are my chances in some top notch physics department? I want to do research in theoretical high energy physics.(I should also mention that I have done no experiments after high school.)
2. Do I need to take the physics GRE? I have already taken the math GRE.
3. How should I phrase the statement of purpose? In particular, how should I explain my decision of moving from math to physics? And any thoughts on how to portray my strength in math as an advantage? I want to do research on theoretical high energy physics. So it would be very helpful if someone can provide a link to the statement of a similar applicant.
4. What about European universities? I don't know much about the application procedure there.
5. My current university has a quite good physics program. Is it possible to transition within the university without all the hassles of a new application procedure? I have heard stories of many people who have changed departments in gradschool(Witten himself).
How does that work? Should I just email some professors in the physics department and rest my case to them?
6. This is a tricky question. If all my efforts come to naught and I fail to secure admission in any of the places I apply I would like to complete my current PhD in math. However I plan to ask some of my current professors to write letters for me. So they would know that I was planning to go away. Would that have some repercussions in future?

Waiting eagerly for your replies. Thanks in advance.

 

[prince123]

Sorry I forgot to mention one point. I am an international student with a F1 visa. Do I need to update my I-20 or is there any other complications because of that?

 

[n1person]

1. One primary issue with applying to/getting into a top US graduate program with your background is a fair amount of weight is given to research experience (they don't want people coming into their program who won't be helpful in their lab). This is doesn't make it impossible, but it is a hurdle.
2. For most top US physics phd programs a physics GRE is required. Math GRE won't really count for anything.
5-6. I think it might be a good idea to talk to a few math professors about your questions/worries. I don't think most professors will begrudge you for liking physics and having some degree of inner conflict over math vs physics.