I have dual undergrad degrees in math and physics from US undergrad program. I am currently in physics graduate school. I am intending to apply as an international student for pure math phd with focusing on math physics as my physics phd program does not offer me such an option. I am interested in geometry and topology focusing on hodge theory related to string/superstring theory. My master physics GPA is about 3.58ish. I have not done math for 3 years so far. I got my Oct math gre score 850(88%) and my physics gre score taken previously was 970(92%). What is the chance that I can get into pure math graduate school? Say at the level of brandeis university math or caltech math.
Caltech is a long shot. It's a very selective and small program, and being international will not help. You are probably competitive at several good schools if you have strong letters and a good SoP. I don't think your Master's GPA is going to help you, but they may not care too much about it, I'm not really sure.