David Shaw
Lead Analyst, Global Quantum Intelligence
Quantum Error Correction
Efficiency Through Connectivity
Efficient Error Correction
Fast and Lean QLDPC Codes
Photonic’s groundbreaking implementation of Quantum Low-Density Parity Check (QLDPC) codes provides efficient, fault-tolerant quantum computing, matching the best performance of surface codes and offering lower physical overheads, thereby accelerating the timeframe to commercially valuable quantum computing. Photonic’s unique implementation of the SHYPS family of QLDPC codes is the first to execute both quantum logic and error correction efficiently. It uses non-local connectivity to encode multiple logical qubits in a single code block – for up to 20x fewer physical qubits per logical qubit.
qldpc First
Overcoming Error Correction Limitations
With QLDPC Codes
Photonic developed the first new family of error correction codes—SHYPS QLDPC codes—capable of performing both quantum logic and error correction. QLDPC codes are much more efficient than surface codes—the best option until now—greatly reducing the overhead requirements for quantum systems.
Error correction codes use groups of physical qubits working together to create the error corrected, or logical, qubits necessary for fault tolerant quantum computing. The most effective quantum error correction approach was proximity-based surface codes. These take many steps to transfer information, requiring many more physical qubits for each logical qubit. The fewer physical qubits required for one logical qubit, the lower the system overhead, accelerating the path to useful applications.
QLDPC codes (a quantum version of the LDPC codes used extensively in classical computing) demand high-connectivity instead of proximity. Photonic’s Entanglement First™ architecture’s flexible any-to-any connectivity enables QLPDC codes. Quantum applications are now 20x closer than previously thought.
qldpc Explained
See How QLDPC
Improves Performance
This short video shows how Photonic’s QLDPC codes deliver significant performance gains over surface codes and unlock more efficient quantum computation with QLDPC.
Photonic Advantage
QLPDC Error Correction
Bringing Commercial-Scale Applications Sooner
Improved Physical to Logical Qubit Ratio: 20x fewer physical qubits required per error-corrected logical qubit
Efficient Logical Operations: Competitive with the performance standard set by surface codes
Good Error Suppression: Equal pseudo-threshold performance using far fewer physical qubits
Single-shot Capabilities: One error check per logical operation, reducing runtime by 30x
Fault-Tolerant Operations: Efficient containment of errors as they occur to reduce spread
High connectivity unlocks QLDPC code efficiencies
Qubits that connect only to nearest neighbours are limited to the use of surface codes, resulting in high physical-to-logical qubit ratios. The extensive connectivity of our Entanglement First™ architecture enables access to the most efficient error correction codes available, reducing logical qubit count while ensuring efficient logical operations.
High physical qubit fidelity supports error correction
Above a certain error threshold level, error correction cannot compensate. T centres offer high qubit fidelity, reducing errors and enabling effective error correction. When used with QLDPC codes, key performance metrics for logical operations efficiency, error suppression, and fault-tolerance meet or exceed those of surface codes.
Single-shot error checking offers dramatic speedup
Surface code logic requires 30 measurements in a single clock cycle to achieve one commercial-grade logic operation step. Photonic's QLDPC code requires only one 'single-shot' error check per logical operation. This decreases the clock cycle, computational complexity, and total runtime of the code dramatically, as well as the demands on the hardware.
Non-local linking reduces overhead, scales faster
Planar qubit platforms are limited to a single plane for routing connections between qubits, and one logical qubit per block. Photonic’s approach uses high qubit connectivity and QLDPC codes to encode multiple logical qubits in a single code block, reducing qubit overheads initially by up to 10x, with further improvements as the code block scales.
QLDPC In the News
Error Correction Codes to Accelerate the Timeline to Useful Quantum
“This is a truly major milestone. The quantum field must now be divided into those whose hardware can run these new codes, and those who can’t. We’re going to see a race between players that invest in the scarce skills required for in-house code innovation, and those that seek to be fast followers. Implementing logic always looked like the hard part of standing-up better codes. This new work has knocked it out of the park.“
“This is a truly major milestone. The quantum field must now be divided into those whose hardware can run these new codes, and those who can’t. We’re going to see a race between players that invest in the scarce skills required for in-house code innovation, and those that seek to be fast followers. Implementing logic always looked like the hard part of standing-up better codes. This new work has knocked it out of the park.“
Error Correction Resources