qLDPC Library:Quantum Error-Correcting Code Research
Library qLDPC
Infleqtion researchers and JPMorgan Chase introduced a new open-source research software library today to speed up quantum application efficiency efforts. The Economist Commercialising Quantum conference in London on May 13–14 will provide more details on the news.
In conjunction with JPMorgan Chase, Infleqtion researchers created the open-source qLDPC library. Available on GitHub.
The main reason for this package was to help build and analyse quantum low density parity check (qLDPC) codes. However, the library tools also work for general error-correcting stabiliser and subsystem codes.
Reducing the number of physical qubits needed for quantum error correcting is one of the qLDPC library's biggest benefits. This library reduces fault-tolerant quantum computing hardware requirements by 10–100x. A single logical, error-corrected qubit used to need 1,500 physical qubits to work reliably. This new library may lower the requirement to 15–150 physical qubits per logical qubit, depending on implementation. This breakthrough fixes a scaling quantum system bottleneck.
The qLDPC library tools suit Infleqtion's neutral atom-based quantum computing technology. Infleqtion's hardware enables for extremely customisable qubit layouts, enabling the library's more efficient error-correcting codes.
The open-source library qLDPC is meant for collaboration. Developers, academics, and hardware partners can directly interact with the codebase to find new error correction and quantum workload optimisation approaches across platforms.
Important qLDPC library features include:
ClassicalCode: A class for classical linear error-correcting codes over finite fields, featuring pre-defined families and GAP/GUAVA package communication for more codes.
A class for creating stabiliser and subsystem Galois-qudit codes. Get_logical_ops, concatenate, and get_distance perform nontrivial logical Pauli operator construction, code concatenation, and code distance computation, respectively.
CSSCode: QuditCode subclass for building quantum CSS codes from two suitable ClassicalCodes. It uses research paper approaches to estimate code distance upper bounds in get_distance_bound.
Special quantum code constructs and family classes:
Two-block quantum codes.
BBCode, bivariate bicycle codes, including toric layout identification (like long-distance checks) and neutral atom qubit layouts that minimise communication distance. Several arXiv papers mention these constructs.
Product hypergraph codes.
Product codes for subsystem hypergraphs.
Subsystem hypergraph product codes simplex.
Lifted product codes.
Quantum Tanner codes.
decoders.py: BP-OSD, BP-LSD, belief-field, minimum-weight perfect matching, and additional error decoding modules.An interface for custom decoders is included.
Abstract algebra (groups, algebras, representations) module in Python. It communicates with GAP and GroupNames.org and uses SymPy pre-defined groups.
objects.py: A package for building quantum code auxiliary objects like Cayley and chain complexes.
qldpc.circuits.get_transversal_ops: A qubit code subroutine that constructs all SWAP-transversal logical Clifford gates in one code block, but it has exponential complexity and is more suitable for small-to-moderate codes.
Package requires Python >= 3.10 and can be installed via PyPI or source. C compilers for Windows and cvxpy for macOS may be required.
The project wants detailed documentation, however the current material is outdated. For help using the library's classes and methods, consult the source code, comments, examples directory, and test files.
