Info Theory
I recently finished a book on Information Theory that I'll talk more about later (maybe). The first half of this video covers some of the ideas from the book (they don't mention it, but I'm sure they've read it). The second half deals with free will (I need to find a good book on that topic) and makes the claim that Quantum Mechanics makes free will possible. There's not consensus on that claim in the physics community (there are plenty of physicists who don't believe in free will), but it's an interesting idea.
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Determinism (made famous by LaPlace) basically says that in newtonian mechanics all particles behave exactly as physical laws predict (and newtonian laws only predict a single outcome), so if it were possible to know the states (positions and momenta) of all particles in the universe you can iterate forward and backward in time with complete certainty. The scientist typically takes all mental activity to be the result of the interactions of matter in our brain, so even all thought and seemingly willful actions are already written in stone.
Enter quantum mechanics. It does not predict single outcomes with certainty, just the probabilities of a variety of outcomes (though some point out that these probabilities are known with certainty). Again I haven't studied the precise chain of logic typically applied here, but the short of it is: if you short-circuit the argument for Determinism, you avoid the conclusion of no free-will.
There are some other physical arguments against free-will such as the fact that physics treats the past, present, and future on equal footing. In Relativity, for example, one observer's present could include events that are in another observer's past or present. And since no observer is preferred to any other, all observers are justified to claim that their frame of reference is reality. Thus the future is as real and existent as the past and present. Re-enter Determinism and re-exit free-will.