Bayesian integration for hamiltonian parameters of X-ray photoemission and absorption spectroscopy

Abstract

X-ray photoemission spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) are powerful techniques for revealing Hamiltonian parameters in strongly correlated electron systems. XPS and XAS spectra contain complementary information about the electronic states, meaning that the integrated analysis of XPS and XAS is important for examining the Hamiltonian parameters. In previous research, integrated analysis based on physical knowledge was applied to XPS and XAS. In this paper, we propose Bayesian integration, a framework for integrating XPS and XAS, and demonstrated that it can improve the estimation accuracy and extract information from the spectra with poor S=N ratio. Bayesian integration enables us to estimate the unified Hamiltonian from various measurements and to approach the true electronic structures of materials.