It’s not easy, getting a PhD in physics. Not only must you learn a lot, but some of what you learn will shake your sense of self.
Physics deals with the most fundamental laws of nature, those from which everything else derives. These laws are, to our best current knowledge, differential equations. Given those equations and the configuration of a system at one particular time, you can calculate what happens at all other times.
That is for what the universe without quantum mechanics is concerned. Add quantum mechanics, and you introduce a random element into some events. Importantly, this randomness in quantum mechanics is irreducible. It is not due to lack of information. In quantum mechanics, some things that happen are just not determined, and nothing you or I or anyone can do will determine them.
Taken together, this means that the part of your future which is not already determined is due to random chance.Ittherefore makes no sense to say that humans have free will.