Physics does not emphasize this, but the
half life concept essentially assumes a Poisson process (Cinlar,
Stochastic Processes) which has a Markov (past and future conditionally independent given the present, details from the Radon-Nikodym theorem, with a cute von Neumann polynomial proof, Rudin,
Real and Complex Analysis) assumption.
The half life concept seems to be standard over much of physics.
That a Markov assumption could hold might suggest some new physics.