I am pursuing a course on Coursera and one of the other student in the course is pursuing PhD at UC Davis after retiring from the job. You can also watch the video of James Clewett on Sixty Symbols on Youtube, he started working on a PhD after 8 years of industry work. I have personally known a few people who embark upon this after break, and it is not a bad idea.

As you have been working professionally you already have the rigor, which unfortunately not many academicians do not know about, as they have never worked outside of academia. The only thing lacking will be knowledge and that is what you seek for.

I have completed my M.Sc in Physics with specialization in Quantum Field theory. However, I have average CGPA of 3.35/6 in all the subjects, due to health issues. I completed the course in 2011.

I have some work done independently on Non-Hermitian Quantum mechanics and also hold a fellowship to pursue PhD by CSIR,India. It is earned by ranking in a Physics examination which is applied for, by thousands of students for Physics itself at a single time. I got selected to Pune University, through and nationwide entrance test, too. I also have experience of working in an industry for a startup.

However, whenever I apply to a place, the only reply I get is I did not meet their stringent requirements. I do not know what to do and how to convince. I just want to ask if it is this much competitive to get into a PhD program ! Any steps I need to take to improve my chances?