Edit: To be fair, I'll provide an example of what I mean. David Chalmer's "hard problem of consciousness" is about why we have qualitative experiences. You can explain all of our brain states in functional ways, like pain's function is to prevent damage, but that would still not answer the question of why pain hurts. I don't think science can answer that question, at least not in a way that is observable and testable.
That is the point many in this thread are trying to make. The essence of the question is usually more persistent than it first seems.
That the physical can influence or even determine the mental has been known for at least as long as 3000 years. Those particular experiments you reference don't add much to the philosophical discussion of libertarianism at all.
However, I think the true philosophical problem of free will is deciding what exactly a "will" is and what it means to be "free". You've got to answer that question before you can decide whether free will is compatible or incompatible with determinism.