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Variational system identification is a new formulation of maximum likelihood for estimation of parameters of dynamical systems subject to process and measurement noise, such as aircraft flying in turbulence. This formulation is an alternative to the filter-error method that circumvents the solution of a Riccati equation and does not have problems with unstable predictors. In this paper, variational system identification is demonstrated for estimating aircraft parameters from real flight-test data. The results show that, in real applications of practical interest, it has better convergence properties than the filter-error method, reaching the optimum even when null initial guesses are used for all parameters and decision variables. This paper also presents the theory behind the method and practical recommendations for its use. 

La0.7Sr0.3MnO3 (LSMO) is a promising material for spintronic applications due to its robust ferromagnetism and complete spin polarization. However, these properties are known to degrade in thin films. Oxygen vacancies are believed to be a critical factor in this degradation, but experimentally isolating their effects has proven challenging. In this work, we use first-principles calculations to theoretically investigate how oxygen vacancies affect the magnetic structure of LSMO thin films. Our results reveal that oxygen vacancies act as scattering centers, leading to charge redistribution within the bulk layers. This redistribution disrupts the ferromagnetic double-exchange interaction and introduces competing super-exchange interactions, causing local spin flipping and ultimately reducing the overall magnetization. 

We conducted a first-principles study of FeCl2, focusing on the significance of strong electron correlations using the GGA+U approximation and van der Waals (vdW) interactions to enhance its physicochemical properties description. Our results provide an excellent characterization of both the bulk CdCl2-type structure and the 2D phase 1T crystal structure. We found that both phases were elastically and dynamically stable, showing good agreement with the experimental data from IR, Raman, inelastic neutron scattering, and magnetic measurements. The impact of the FeCl2 dimensionality is discussed in detail. Additionally, we investigated the less-explored distorted 1T phase (1T’), where structural distortions introduce anisotropies that notably affect its properties, particularly its semiconducting behavior. Moreover, our analysis of the magnon spectrum aligns with the recently characterized magnetic properties of the FM 1T phase. Simultaneously, magnetic anisotropy calculations revealed that the 1T’ configuration exhibits greater stability in the presence of an external magnetic field. 

Single photon quantum materials discovery based on large dataset synthetic data generation.