QuTech Demonstrates High-Fidelity Two-Qubit Logic and Quantum Teleportation with Mobile Spin Qubits on Silicon
Tags Infrastructure · Hardware
Researchers at QuTech (TU Delft and TNO) demonstrated two-qubit entangling gates with ~99% fidelity and post-selected quantum teleportation with ~87% fidelity across 320nm using mobile electron spin qubits shuttled on a silicon-germanium chip via a 'conveyor belt' method, published in Nature in May 2026. The experiments used a six-dot linear array with parity readout ancillas in isotopically pure 28Si/SiGe at ~200 mK. The mobile qubits are transported via travelling wave potentials from phase-shifted sinusoidal voltages on gate electrodes, achieving conditional post-selected teleportation well above the classical limit of 66.7%. This upgrades mobile spins from a transport layer to a universal primitive for large-scale quantum processors, enabling any-to-any connectivity in semiconductor quantum computing.
Technical significance
The demonstration of high-fidelity two-qubit gates between mobile spins on silicon closes a key gap between 'moving memory' and 'moving computation' in semiconductor quantum processors. The ~99% fidelity for shuttling-based entangling gates meets the threshold for error-correction thinking, and the silicon-germanium platform is compatible with existing foundry processes. If mobile semiconductor qubits survive benchmarking against static arrays, this could become the credible path for flexible, factory-style quantum processors.