I am currently a mathematics PhD student. I am switching field and applying to physics graduate programs. I need some tips regarding how to explain my transition from math to physics. What to write in my statement to explain this? I have been always interested in physics and while pursuing the math PhD I took courses from the physics department which deepened my desire to do research in physics.

Also my area of interest is hep-th, in particular string theory, which has a lot of applications of advanced mathematics. I am featuring it as a strong point in my statement. Any idea regarding this will also be greatly appreciated.