Quantum Speed Limits for Time Evolution of a System Subspace

One of the fundamental physical limits on speed time evolution a quantum state is known in form celebrated Mandelstam–Tamm inequality. This inequality gives an answer to question how fast isolated system can evolve from its initial orthogonal one. In turn, Fleming bound extension that optimal for between non-orthogonal and final states. present work, we are concerned not with single but whole (possibly infinite-dimensional) subspace states subject Schrödinger evolution. By using concept maximal angle subspaces derive estimate such may be viewed as natural generalization bound.