http://news.poseidon-us.com/TGPw5C
Researchers have succeeded in building a quantum computer gate based on a double-transmon coupler (DTC), which had been proposed theoretically as a device that could significantly enhance the fidelity of quantum gates. Using this, they achieved a fidelity of 99.92 percent for a two-qubit device known as a CZ gate and 99.98 percent for a single-qubit gate.
http://news.poseidon-us.com/TGPw5C
http://news.poseidon-us.com/TGPw5C