Effect of high frequency modes of medium on an open quantum system

We present a method to calculate the real time effective propagator of a generic open quantum system, immersed in a medium using a wave function based framework. The medium is characterized by a set of harmonic oscillators having a continuous span of frequencies. This technique has been applied to the Caldeira–Leggett model showing that high frequency modes of the medium do not contribute towards decay of the population of states of the open system. In fact, they cause a Rabi-type oscillation. Moreover, our wave function based approach provides an excellent alternative to conventional formalisms involving the density matrix.