Nuclear physics is sometimes considered to be a dead subject sometimes, by some people. I dont think that is the case. Its merely not fashionable for many people. And why not? Maybe it does not have high sounding terminology embedded in it. Anyway, in this entry I will try to argue that it is indeed interesting,--very interesting; and some very cool features can be seen in it. Since I am not a nuclear physicist, my description will be rudimentary.
Lets come to the concept of non-relativistic conformal field theories. Suppose you have a set of fermions interacting with each other. Then there is a phase shift associated with the incoming and outgoing fermion wavefunctions. Now imagine, that the interactions between the fermions can be tuned by tuning some coupling, say the magnetic field. For strong coupling, the fermions could be bound into fermions, while for arbitrary weak coupling they would form a Cooper-pair type bound state. The scattering length changes sign in these two phases, and at the point of transition it diverges, giving rise to universal physics. Thats the non-relativistic conformal fixed point I was referring to.
Now about the nuclear physics connection. The nucleon-nucleon (N-N) scattering length is of prime importance in nuclear physics. For real world, its small and negative for the pion phase shift in a particular channel. It is believed that tuning the quark mass would change the sign of the pion phase shift! The quark mass plays the role of the coupling in the previous example.
I am not yet aware of the implications of this interesting phenomena, but I do intend to find out.
True, I have glossed over the details, but I will add a more complete picture as and when I get it.
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