Quantum researchers crack more efficient error-correction code for practical machines
Scientists have designed a new quantum error-correction system that uses five times fewer physical components than current industry standards while maintaining equal reliability. The breakthrough could accelerate the timeline for building commercially viable quantum computers by dramatically reducing the hardware costs and engineering complexity that currently limit deployment.
Originaltitel: High-Threshold, Low-Overhead and Single-Shot Decodable Fault-Tolerant Quantum Memory
We present a family of quantum low-density parity-check codes, which we call radial codes, obtained from the lifted product of a specific subset of classical quasicyclic codes. The codes are defined using a pair of integers <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mo stretchy="false">(</a:mo> <a:mi>r</a:mi> <a:mo>,</a:mo> <a:mi>s</a:mi> <a:mo stretchy="false">)</a:mo> </a:math> and have parameters <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mtext>⟦</e:mtext> <e:mn>2</e:mn> <e:msup> <e:mi>r</e:mi> <e:mn>2</e:mn> </e:msup> <e:mi>s</e:mi> <e:mo>,</e:mo> <e:mn>2</e:mn> <e:mo stretchy="false">(</e:mo> <e:mi>r</e:mi> <e:mo>−</e:mo> <e:mn>1</e:mn> <e:msup> <e:mo stretchy="false">)</e:mo> <e:mn>2</e:mn> </e:msup> <e:mo>,</e:mo> <e:mo>≤</e:mo> <e:mn>2</e:mn> <e:mi>s</e:mi> <e:mtext>⟧</e:mtext> </e:math> , with numerical studies suggesting average-case distance linear in <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:mi>s</i:mi> </i:math> . In simulations of circuit-level noise, we observe comparable error suppression to surface codes of similar distance while using approximately five times fewer physical qubits. This is true even when radial codes are decoded using a single-shot approach, which can allow for faster logical clock speeds and reduced decoding complexity. We describe an intuitive visual representation, canonical basis of logical operators and optimal-length stabilizer measurement circuits for these codes, and argue that their error correction capabilities, tunable parameters and small size make them promising candidates for implementation on near-term quantum devices.