Researchers say China’s improvements in quantum computing will help its armed forces, which are the world’s third strongest. Quantum computing is a kind of computing that lets high-powered machines solve problems that are too difficult for normal computers. The idea for quantum computing was discovered by American physicist Richard Feynman in 1980. International Institute for Strategic Studies said in a 2019 study that it has two important military uses. It can understand secret military messages and it can break into secure communications. Alexander Vuving is a professor at the Daniel K. Inouye Asia-Pacific center for security studies in Hawaii. He...