Session 05 - CSS Tanner Graphs and Spectral Expansion

Status: covered from Heptabase lesson 522a7430-2dd1-4dec-876c-200f63397af5.

Covered Material

• Separate X-type and Z-type Tanner graphs for a CSS code.
• Even-overlap graph interpretation of CSS commutativity.
• Adjacency spectra of regular graphs.
• Petersen graph as the first small expander example.

Source Anchors

• quantum-tanner-diagonal-expansion-structure.md
• quantum-tanner-expander-anchor.md

Retention Check

Ask the learner to explain why the all-ones vector is the top eigenvector of a connected regular graph.