Diffusive Limit of Non-Markovian Quantum Jumps
: Kimmo Luoma, Walter T. Strunz, Jyrki Piilo
Publisher: AMER PHYSICAL SOC
: 2020
: Physical Review Letters
: PHYSICAL REVIEW LETTERS
: PHYS REV LETT
: ARTN 150403
: 125
: 15
: 6
: 0031-9007
: 1079-7114
DOI: https://doi.org/10.1103/PhysRevLett.125.150403
: https://doi.org/10.1103/PhysRevLett.125.150403
: https://research.utu.fi/converis/portal/detail/Publication/50729962
We solve two long-standing problems for stochastic descriptions of open quantum system dynamics. First, we find the classical stochastic processes corresponding to non-Markovian quantum state diffusion and non-Markovian quantum jumps in projective Hilbert space. Second, we show that the diffusive limit of non-Markovian quantum jumps can be taken on the projective Hilbert space in such a way that it coincides with non-Markovian quantum state diffusion. However, the very same limit taken on the Hilbert space leads to a completely new diffusive unraveling, which we call non-Markovian quantum diffusion. Further, we expand the applicability of non-Markovian quantum jumps and non-Markovian quantum diffusion by using a kernel smoothing technique allowing a significant simplification in their use. Lastly, we demonstrate the applicability of our results by studying a driven dissipative two level atom in a non-Markovian regime using all of the three methods.