Of course, string theory has a high energy scale, and since it is so high that very little experiments can probe the theory itself. But nowadays it comes down to the energy scalr of a few MeV… that is the scale of nuclear physics. In between, there resides hadron physics and elementary particle physics, but, string theory could jump those scales and came down to the nuclear physics energy scale — that is what I am studying right now.
The basic ingredients of nuclear physics is nuclear force, the force between nucleons. The long-standing problem in nuclear physics is that there has been no direct derivation of the nuclear force from strongly coupled QCD. String theory now provides a new tool for resolving this issue, in a strange manner : holography. Together with my collaborators, I worked out the “derivation” of the nuclear force from QCD, in the large N_c limit and in the large ‘tHooft coupling (strong coupling) limit. Amazingly, string theory computes the repulsive core of nucleons, which has been known for more than 50, 60, 70 years. the computation revealed that the main source of the repulsive core is omega meson. This is indeed the case which Yoichiro Nambu predicted more than 50 years ago! As you may know, Nambu is one of the founders of string theory. So, we here see that two different findings of Nambu meet each other, after 50 years of reccurence time.
If this is regarded as a success, one can say that string theory provides a new and powerful tool for nuclear physics. Among my works, my favorite is the one which provides a gravity dual of heavy nuclei. Some related works are in progress. You will see more on how string theory can be applied to nuclear physics. Let me keep posted on this.