Yu-Hao Deng

A laser pulse lasting one and a half nanoseconds hits a nonlinear crystal, and a stream of squeezed light is born. That is how an experiment on the Jiuzhang 4.0 quantum processor in China begins.

Even at absolute rest, atoms emit a faint noise — unavoidable quantum jitter. In the debates between Einstein and Bohr, this noise, like an unceasing whisper, blurs the interference fringes from an atomic slit. Overcoming this limit was considered impossible.