Quantum mechanical model for two-state jump Markovian process

A quantum mechanical model is given which is equivalent to the stochastic dephasing subject to the two-state jump Markovian process. The stochastic variable corresponds to a Hermitian operator of a spin-1/2 system which is embedded in a thermal reservoir, where the time-evolution of the spin-1/2 system is described by the quantum master equation of the Lindblad form.