The ‘holy grail’ of particle physics is being to explain all of the forces in nature with one theory – the thing that’s left out most of the time is gravity, it just doesn’t fit in with most of the other theories. Quantum chromodynamics (QCD) is the theory that describes the nuclear strong force – the forces between quarks and gluons inside protons and other hadrons. It would be great if we could unify this with gravity and with the other main force – electroweak theory, which incorporates electromagnetic forces and the weak nuclear force.
In theoretical physics, quantum chromodynamics (QCD) is a theory of the strong interaction. This is a fundamental force describing the interactions of the quarks and gluons making up hadrons (protons and neutrons). At the moment it is still a theory though!
QCD has two main facts:
1. “Confinement”, which means that the force between quarks doesnt decrease as they are separated. Because of this, it would take an infinite amount of energy to separate two quarks.
2. “Asymptotic freedom”, which means that in very high-energy reactions, quarks and gluons interact very weakly.
If you can pull together the theory of QCD and gravity then this could be evidence of the Grand Unified Theory (GUT) which says that everything, including gravity, comes from one single law.