Cracking CSIR is always advantageous if you want to go for research in any basic science and applied science subjects. GATE qualified candidates can also pursue Ph. D but the condition is the rank should be very high. Not only Ph. D , top rankers in GATE are eligible for competing for Shyam Prasad Mukherjee (SPM) fellowship also. Its better if you have a fellowship from CSIR or UGC. It helps to enter in Ph.D. course of any university or research organisation easily. Once you are qualified in CSIR it is your choice to select the institute and guide as well.
If you are not able to get any fellowship then the only option lies in joining in a project with some scientist or Professor in any University in your field. Further you can pursue your doctoral degree if concerned professor has a project in which there is a JRF position. Following premier educational institutions offer courses in Physics:
1. Indian Institutes of Technology (There are Integrated M.Sc.-Ph.D. Courses in IIT Kharagpur for which admission will be through IIT JAM.
2. Central Universities. Most of the central universities along with University of Hyderabad, Delhi University, Pune University offering Physics course.
3. There are centrally funded laboratories to offer research courses in the basic discipline such as Physics.
4. State level universities like Osmania University, Bharatiar University, Calicut University also offer M.Sc. and Ph.D in Physics.
5. Anna University, Chennai, Tamilnadu offers good programme.
Admission to all of these institutes will be through entrance examinations by respective universities and boards. Most of universities conduct objective type entrance tests for M.Sc. Courses and Objective / Descriptive tests for Research Courses. You can get more details of admissions through concerned university website.