/sci/ - Science & Math

>>11490933
Sure let's turn this into /pg/.
>what is a ground state?
Ground states are quantum states of the lowest energy.
>topologically degenerate
Degeneracy of the ground state means you have multiple states with the same lowest energy, and topologically degenerate means the distinct ground states are labeled by a topological invariant. The pion vertices, the chiral anomaly and more generally the obstructions I mentioned are such examples of these topological invariants.
>What is a cosmic string and why's it important in cosmology?
It's a string of defects in spacetime, like a 1D blackhole/2-brane. It's important because they show up when studying possible mechanisms for spontaneous symmetry breaking in order to explain e.g. DM, DE, strong CPT violation, and other things in cosmology and HEP.

If you're interested it'd be good for you to read up on intro QFT from e.g. Weinberg or Peskin-Schroeder, it'll give you a more solid understanding.