Sandia and Quantinuum Introduce Logical Gate Set Tomography to Map Fault-Tolerant Qubit Noise
quantumcomputingreport.com Oct 31, 2026

Sandia and Quantinuum Introduce Logical Gate Set Tomography to Map Fault-Tolerant Qubit Noise

AI-summarised brief · reviewed before publication

Sandia National Laboratories and Quantinuum have unveiled Logical Gate Set Tomography (Logical GST), a tomographic reconstruction of a single‑qubit logical gate set on a processor. The technique was demonstrated on Quantinuum’s 20‑qubit trapped‑ion H1‑1 system, encoding a logical qubit with the [[7,1,3]] Steane code and employing feed‑forward to apply correction pulses during gate operations. Logical GST characterized initialization, measurement, transversal Clifford gates and a T‑gate implemented via magic‑state injection, achieving a 95.9 % acceptance rate. Experimental data with 50 shots per circuit matched a Pauli‑stochastic noise model and showed no significant non‑Markovian effects, while high‑shot emulator runs exposed coherent over‑rotations and non‑Markovian drift linked to ion transport and cooling. The method offers a tool to verify noise assumptions for fault‑tolerant decoders.

💡 Why It Matters

  • · It provides the first hardware‑agnostic check that real‑world fault‑tolerant qubits obey the simplified noise models decoders rely on.