I would like to pose a question about neutron density, such as the neutron desnity that stems from the collapse of a large star. Is the resultant neutron density only there due to gravity, or is it a stable state of neutrons that would continue to exist even without gravity (hypothetically)? In other words, in our normal world, neutrons do not form nuclear bonds with just other neutrons. They need protons. Does this repulsion between neutrons hold true for neutron stars or does the gravity compression decrease the distance between neutrons to a critical distance to where the nuclear repulsion force becomes attractive and the neutron density becomes a stable state of matter?

It's about gravity overcoming all other forces in the end.

That would imply a meta-stable state where outward repulsion between neutrons is overcome by gravity. What is interesting about this scenario is that gravity and nuclear repulsion could theoretically form a delicate state of balance. If gravity was to decrease, due to matter becoming energy, the neutron density will expand again?

That would imply a meta-stable state where outward repulsion between neutrons is overcome by gravity. What is interesting about this scenario is that gravity and nuclear repulsion could theoretically form a delicate state of balance. If gravity was to decrease, due to matter becoming energy, the neutron density will expand again?

 

In a neutron star it is in balance, more mass and the system collapses into a black hole.

I would like to pose a question about neutron density, such as the neutron desnity that stems from the collapse of a large star. Is the resultant neutron density only there due to gravity, or is it a stable state of neutrons that would continue to exist even without gravity (hypothetically)? In other words, in our normal world, neutrons do not form nuclear bonds with just other neutrons. They need protons. Does this repulsion between neutrons hold true for neutron stars or does the gravity compression decrease the distance between neutrons to a critical distance to where the nuclear repulsion force becomes attractive and the neutron density becomes a stable state of matter?

 

The repulsion is from degenerate neutron pressure, a consequence of the Pauli exclusion principle. The nuclear force is attractive; neutrons do attract other neutrons (i.e. there are bonds) but since there is always an available proton level available, bound neutrons will tend to decay.