A tight quantum speed limit for open quantum dynamics

Determining the speed of the quantum dynamics of a system is significantly important in many physical studies. The faster dynamics in quantum gates can escalate the speed of computation. In condensed matter physics, determining how fast correlations can be spread in many-body systems, relies on the dynamical speed of the system. Finally, in black hole physics, the entropy change rate of the system is limited by the speed of quantum dynamics.
Quantum Speed Limit imposes a bound on the speed of evolution of all quantum processes. However, in spite of their significant importance, the existing bounds are usually not tight, which underestimate the best possible speedup, and they usually are difficult to compute. Overcoming these issues becomes even more challenging when we deal with open quantum systems. In this work, we present a new quantum speed limit, which resolves both tightness and computability issues. Unlike most of speed limits, this limit is applicable to any open or closed quantum dynamics.