## The second quantum revolution

来源：未知 作者：唐机 时间：2019-03-14 11:03:07

By Michael Brooks THE world used to be a much simpler place. A hundred years or so ago, we lived in a very normal, classical universe where everything made sense, and nothing behaved strangely. Then along came quantum theory. Suddenly, stuff didn’t always behave as any rational person would expect. At the fundamental level of atoms and particles, things could be in two places at once. They could even move in two different directions at once. And it seemed they could also be entangled – engaged in a quantum version of telepathy in which they are somehow able to sense and affect each other instantaneously from a distance. Adjusting to this new universe was a tall order. Some physicists constructed elaborate philosophies to deal with the implications. Albert Einstein, on the other hand, famously rejected entanglement as “spooky”. He was convinced that quantum entanglement couldn’t be real because the implications would run too deep: any effort to produce a unified theory, one that tied quantum mechanics together with relativity and other physical theories, would need to reconcile the weirdness of entanglement with relativity’s rather more practical grasp of time and space. That just seemed altogether too hard. Not that he ever gave up on a theory of everything. Einstein spent the latter part of his life trying to construct a unified universe, without success. He also continued to wrestle with quantum spookiness on his own. To most physicists, quantum theory was useful if you wanted to design a laser or transistor,