Long-Range Interactions Accelerate Fast State Transfer and Entanglement Renormalization
How fast can entanglement be spread between two distant points? It depends on the strength and range of the interaction. For short-range systems, the time to generate an entangled state between two points will be linear in the distance between them. For long-range interacting systems, we can usually do better, but how much better is an open question.
Some recent progress on quantum information complexity
Information complexity (IC) was introduced around 2000 to study communication complexity (CC) and it turns out to be one of the most powerful methods. Many elegant message-compression algorithms have been discovered to compress protocols with low IC since then.
Kinetic theory of dark solitons with tunable friction
We study controllable friction in a system consisting of a dark soliton in a one-dimensional Bose gas and a non-interacting Fermi gas. The fermions act as impurity atoms, not part of the original condensate, that scatter off of the soliton. We investigate semiclassical dynamics of the dark soliton, a particle-like object with negative mass, and calculate its friction coefficient. Surprisingly, the amount of friction depends on the ratio of interspecies (impurity-condensate) to intraspecies (condensate-condensate) interaction strengths.