A tiny satellite has enabled quantum-encrypted information to be sent between China and South Africa, the farthest distance yet achieved for quantum communication. Using a laser-based system, a team in the city of Hefei was able to beam a 'secret key' encoded in quantum states of photons, to their colleagues over 12,000 km away. This key allowed scrambled messages to be decrypted ' including one containing a picture of the Great Wall of China. The team's system is drastically smaller and cheaper that previous attempts, and they think it represents a big step towards the creation of a global network of secure, quantum communication. Researchers have created an AI system called TextGrad which can provide written feedback on another AI's performance. This feedback is interpretable by humans, which could help researchers tweak the incredibly complicated, and sometimes inscrutable models that underpin modern AIs. 'Previously optimising machine learning algorithms requires quite a lot of...
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