Construction methods

Other QLDPC constructions

Affine-coset, two-branch, random, and finite-degree approaches to quantum LDPC code design.

These pages give the construction idea, the particular code instances studied, and their data. Distance statements below refer to the linked paper versions; archived parameter files are identified separately where they define a different instance.

Construction families

Finite-field two-branch construction

A two-branch construction of regular CSS bases. The P=64 instance used in the paper's error-rate simulations has [[10240, 4108, d]] with 18 ≤ d ≤ 32. An earlier coefficient archive defines a different instance with d=16.

Paper (v3) · Instances and construction data

(3,6)-regular girth-8 construction

Sparse regular CSS checks with girth 8. The representative finite lift has [[28800, 62, d]] with 18 ≤ d ≤ 192, so it encodes 62 logical qubits.

Paper and distance bounds (v3) →

Finite-degree GV construction

An asymptotic distance result reaching the quantum Gilbert–Varshamov bound through classical sparse-graph constructions. The supporting repository provides proof material and verification code.

Paper (v3) · Proof material and programs

Random QLDPC construction

A randomized approach to constructing commuting sparse quantum checks, complementing the explicit block constructions elsewhere on this site.

Paper →

For pair-partition constructions and their development into low-weight canonical logical bases, see PP codes and logical bases. For affine-permutation-matrix constructions, see Kasai codes.