The Chinese company DeepThink has just released its latest AI large language model - and it has caused a massive reaction. It runs rings around the American AI models for how cheaply and efficiently it is produced and trained, while matching those models for performance. The implications have seen tech stocks plunging today, with Nvidia, the main AI chipmaker, leading the fall. While it sounds like just a tech story, it's actually a profound shift in the balance of technological power of the world. Let's discuss.