Researchers have achieved a key milestone toward the development of a fault-tolerant quantum computer. They were able to demonstrate a two-qubit gate fidelity of 99.5 percent — higher than the 99 percent considered to be the threshold for building fault-tolerant computers — using electron spin qubits in silicon, which are promising for large-scale quantum computers as the nanofabrication technology for building them already exists.
Quantum Computers News — ScienceDaily