cold.wit

So, it's about the work done on the two protons to bring them together. That would be their positive potential energy. And the negative energy is equal to the work done to break them apart. But what if there are two opposite charges, and in bring them together there is no work done. What will be the negative energy then?

In nuclear fusion when four protons come together to form two protons and two neutrons making a helium nucleus. The mass is less than the original 4 proton atoms. This is explained by the helium nucleus having the same amount of 'negative energy' equivalent to the mass difference. Now, what is this 'negative energy' precisely...the PE or something else?