  We investigate the quantum-mechanical time-evolution speed limit for neutral
$K$ and $B$ mesons, both single as well as correlated, within the framework of
open quantum systems. The role of coherence--mixing, a crucial feature of the
open system evolution of the underlying quantum systems (here, the mesons), on
the quantum-mechanical time-evolution speed limit is studied. The impact of
decoherence and CP (charge conjugation parity) symmetry violation on
quantum-mechanical time-evolution speed limit is also investigated. The
quantum-mechanical time-evolution speed limit increases with the evolution time
for the single mesons, a signature of the underlying open system dynamics of
the evolution being semi-group in nature. The evolution of the correlated
mesons slows down for an evolution time of approximately one-fourth of the
lifetime, after which it is sped up. An overall pattern that emerges is that
correlated mesons evolve faster as compared to their uncorrelated counterparts,
suggesting that quantum correlations can speed up evolution.
