Norihiro Tanahashi

A drop of cream falls into a cup of coffee, and within a minute, the entire drink turns beige. This mixing process can be quantified: how much "stirring" is needed to transform one distribution of particles into another? In mathematics, this approach is called optimal transport, and the measure of effort is the Wasserstein distance. The authors applied this idea to quantum systems.

Lab-made black holes from superconducting circuits aren’t a trick: they’re an attempt to grab by the tail the most elusive effects, the ones astrophysics so far only glimpses as faint shadows in telescopes.