Calculate the ground state degeneracy (GSD) of a ZN stabilizer Hamiltonian H,
which consists of a sum of products of ZN Pauli operators (with negative coefficients),
so that each operator has eigenvalue +1 in the ground states.
degen.nb is a user friendly Mathematica script to perform the GSD calculation, even for nonprime N.
To download, right click the link below and select "Save link as...":
https://github.com/kjslag/degeneracy/raw/master/degen.nb
degen.hs is an undocumented but faster haskell script to calculate the GSD.
The GSD is calculated using the algorithm described in Appendix B of [1], which is based on [2,3].
[1] Shirley, Slagle, Chen, "Twisted foliated fracton phases", PRB (2020), https://arxiv.org/abs/1907.09048
[2] Gheorghiu, "Standard form of qudit stabilizer groups", PRA (2014), https://arxiv.org/abs/1101.1519
[3] Gottesman, "Stabilizer codes and quantum error correction", PhD Thesis (1997), https://arxiv.org/abs/quant-ph/9705052