I am currently in a problem-solving mode of my PhD (theory, middle stage). I am working on something which is incremental on the last half a year. Until now, I did not get anything non-trivial. I noticed that I have become slow as compared to the initial two years of my PhD.
I am wondering how to speed up my research. I have tried to scan as many papers as possible. I am also trying to discuss my research problem with other students, but it is not working.
Question: Is it natural that you become slower in the middle of your PhD? How can I speed up my research?