[imInGoodCompany]

Not a physicist, but: "expansion" is probably understating it. My guess would be something analogous to an insanely powerful neutron bomb. Interesting thought experiment, would love to see someone do the actual maths.

[SiempreViernes]

"Neutron bomb" just means a nuke that releases a lot of neutrons while not exploding quite as much.

The energy density contained within a bit of neutron star matter makes a big explosion, and that will likely dominate over the more exotic processes.

[vman81]

A 10cm3 cube of neutron star would weigh about a billion tonnes, comparable to a cubic km of water ice. I wonder how all that mass would behave if left to expand with all the exotic physics involved - if it would just sort of... vaporize the planet.