pyqcmlisted
Install: claude install-skill pyqcm-project/pyqcm-skill
# pyqcm
Pyqcm implements three related quantum cluster methods, Cluster Perturbation Theory (CPT), the
Variational Cluster Approach (VCA), and Cellular/Cluster Dynamical Mean Field Theory (CDMFT), for
approximating strongly correlated (Hubbard-like) lattice models. The impurity solver is exact
diagonalization (Lanczos and variants) on sparse matrices. Core numerics are C++; the day-to-day
interface is Python.
This skill covers three distinct jobs. Figure out which one the user needs (often more than one at
once, e.g. debugging a script *and* interpreting why the physics looks wrong) and read the matching
reference file before acting:
| Job | When | Read |
|---|---|---|
| Write or debug a pyqcm script | Defining clusters/models/operators, running ED/CDMFT/VCA, fixing a traceback, choosing sectors | `references/scripting.md` |
| Interpret physics results | Explaining a spectral function, self-energy, order parameter, or phase diagram; connecting output to the underlying theory | `references/physics.md` |
| Modify pyqcm itself | Touching `src_ed/`, `src_qcm/`, `src_python/`, or the pure-Python `pyqcm/*.py` wrapper | `references/contributing.md` |
**Always check `references/gotchas.md` first**, regardless of the job. It is a running list of
hard-won lessons from this research group about pyqcm's sharp edges (conventions, past mistakes,
build quirks) that aren't written down anywhere else. If you learn a new one during a session (a
mistake you made, a surprising API behavior,