We investigate the relationship between non-Markovianity and the effectiveness of a dynamical decoupling (DD) protocol for qubits undergoing pure dephasing. We consider an exact model in which dephasing arises due to a bosonic environment with a spectral density of the Ohmic class. This is parametrized by an Ohmicity parameter by changing which we can model both Markovian and non-Markovian environments. Interestingly, we find that engineering a non-Markovian environment is detrimental to the efficiency of the DD scheme, leading to a worse coherence preservation. We show that each DD pulse reverses the flow of quantum information and, on this basis, we investigate the connection between DD efficiency and the reservoir spectral density. Finally, in the spirit of reservoir engineering, we investigate the optimum system-reservoir parameters for achieving maximum stationary coherences.amplitude-damping-type channels, finding the existence of regimes where non-Markovianity can be either beneficial or detrimental.In the present paper we re-examine a simple example of a DD scheme for a decohering channel in the light of the above mentioned new approach to non-Markovianity. In particular we will assess the performance of DD in the presence of information back-flow, a common quantifier of non-Markovianity. Futhermore, in analogy with the perspective which views DD as a way to engineer environment spectra, here we also study if and how the DD pulses change the non-Markovian character of the dynamics, e.g. whether they induce information back-flow, as defined in [24].The structure of the paper is the following. In section 2 we review the basic definitions of non-Markovianity recently adopted by the open quantum systems community, and we motivate this approach. In section 3 we introduce the system of interest, namely the pure dephasing model including its exact solution in presence of PDD. In section 4, we discuss how the DD pulses affect information flow and hence modify the Markovian/non-Markovian character of the dynamics. In section 5, we investigate whether non-Markovian or Markovian dynamics are best suited to DD, i.e., lead to optimal performance. In section 6, we discuss in the spirit of reservoir engineering, the optimum system parameters for achieving maximum stationary coherences. Finally in section 7 we summarize our findings and draw the conclusions.
A stochastic simulation method designed to study at an atomic resolution the growth kinetics of compounds characterized by the sp3‐type bonding symmetry is presented. Formalization and implementation details are discussed for the particular case of the 3C‐SiC material. A key feature of this numerical tool is the ability to simulate the evolution of both point‐like and extended defects, whereas atom kinetics depend critically on process‐related parameters. In particular, the simulations can describe the surface state of the crystal and the generation/evolution of defects as a function of the initial substrate condition and the calibration of the simulation parameters. Quantitative predictions of the microstructural evolution of the studied systems can be readily compared with the structural characterization of actual processed samples is demonstrated.
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