Chances of getting into a PhD program (Physics) after an MS from another stream (Chemistry) I am an international student who started my PhD program in chemistry at an R1 university in the US, at the beginning of Fall 2019.
As I credited graduate level courses in Physics like Mathematical Physics, Quantum Mechanics, Quantum Optics etc., I realized that I would rather see myself getting a PhD in Physics than in Chemistry. But, COVID-19 made it impossible for me to transition into the physics program at my university. Therefore, I ended up taking summer research credits enough to graduate with an MS in Chemistry.
What are the chances of getting into the graduate program in Physics again if I apply this Fall for starting next Fall?
I'm going to guess that you should do fine. Of course, I'm not going to be on the admissions committee and every one has its own standards, so my prediction may mean little in any individual case.
But I think you have shown some diligence and some awareness of your needs. Changing fields early under the conditions you state seems like a positive thing (as opposed to failing out). You may need to explain a bit about the change in your SoP for any new program, but that should be easy enough.
Of course you will need to meet the entry requirements for any physics program you apply to. And the usual caveats about competition apply.