Original title: Optimal Fusion Strategies for Quantum Computation
Kenneth Goodenough, Andrew Landahl, Joon Lee, Antonio Russo +1 · September 2026
Quantum computers can use particles of light to connect qubits, which are the basic units of quantum data. Linking these units together is called fusion. In light-based setups, physical fusionsActual probabilistic measurements performed on individual qubits that can fail. can fail at random because qubits get measured in product bases, meaning independent fallback directions. If too many fail in the wrong ways, the entire stored message fails. Choosing the specific fallback basis for each qubit is called a fusion strategyA plan for choosing the measurement basis for each qubit when a fusion fails, affecting logical outcomes.. Researchers studied setups that store k=1 encoded qubit. They discovered the rules for perfect fusion strategies, where the overall connection survives even if all physical fusions except one fail. They found these strategies work on quantum parity-check codesA type of quantum error-correcting code that uses parity checks to detect and correct errors., solving an open question. Finally, they proved that random graph codes admit a perfect strategy with a probability exponentially close to 1.
When you cook a meal with multiple steps, sometimes an ingredient goes bad or a step doesn't work out. If too many parts fail, the entire meal is ruined. In this paper, quantum computations require fusing qubits, which are like the cooking steps, and each fusion can fail probabilistically. The perfect fusion strategies ensure that the computation succeeds even when almost all fusions fail, similar to a recipe that tolerates widespread failures.
Building quantum computers and reliable quantum networks requires handling operations that fail randomly. These strategies make fault-tolerant systems more achievable by showing that widespread failures can be managed in many quantum codes.
The paper only addresses codes that encode a single logical qubit and focuses specifically on graph codes. It does not provide strategies for multi-qubit encodings or experimental validation. The results are probabilistic for random codes, not guaranteed for all quantum codes.
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Optimal Fusion Strategies for Quantum Computation — Kenneth Goodenough, Andrew Landahl, Joon Lee et al.
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.