IBM researchers have developed a new decoder algorithm called Relay-BP, which significantly improves the detection and correction of errors in quantum memory. The algorithm, known as Relay-BP, shows a tenfold increase in accuracy over previous leading methods and reduces the computing resources required to implement it. Relay-BP addresses a persistent bottleneck in the quest to build reliable quantum computers and could lead to experimental deployments within the next few years. Quantum computers are sensitive to errors due to their fragile qubits, which can be disturbed by environmental noise or imperfections in control. The decoder works by analyzing syndromes, indirect measurements of quantum states, that provide clues about where something has gone wrong. Relay-BP, built on an improved version of a classical technique called belief propagation (BP), is the most compact, fast, and accurate implementation yet for decoding quantum low-density parity-check (qLDPC) codes. It is designed to overcome trade-offs, being fast enough to keep up with quantum error rates, compact enough to run on field-programmable gate arrays (FPGAs), and flexible enough to adapt to a wide range of qLDPC codes. IBM’s Relay-BP is a quantum error correction algorithm that uses memory tuning, a tool in physics, to improve performance. The algorithm’s success is attributed to the interdisciplinary approach of the team, which combined expertise from firmware engineering, condensed matter physics, software development, and mathematics. IBM credits this cross-functional approach as a cultural strength of its quantum program. Relay-BP currently focuses on decoding for quantum memory, but is still short of full quantum processing. To achieve real-time quantum computation, the decoding must become faster and smaller. IBM plans to begin experimental testing of the decoder in 2026 on Kookaburra, an upcoming system designed to explore fault-tolerant quantum memory. Relay-BP is considered a vital piece of the puzzle, pushing the limits of classical resources to stabilize quantum systems and offering a new tool for researchers looking to bridge the gap between experimental qubits and reliable quantum logic.