Speaker
Description
Electron-boson interaction is quantified through the Eliashberg function $\alpha^2F(\omega,\mathbf{k})$, accessible through the electron self-energy $\Sigma(\varepsilon,\mathbf{k})$. In ARPES, $\Sigma(\varepsilon,\mathbf{k})$ is readily extracted from the spectral function, requiring little more than a parametric expression for the quasiparticle dispersion $\xi(\mathbf{k})$ in order to discern the photoemission kink resulting from $\Sigma(\varepsilon,\mathbf{k})$. However, $\alpha^2F(\omega,\mathbf{k})$ is highly sensitive to the parameters of $\xi(\mathbf{k})$, which itself can be difficult to determine in the presence of strong electron-boson interaction. We will describe a self-consistent and simultaneous Bayesian optimisation method for $\Sigma(\varepsilon,\mathbf{k})$ and $\xi(\mathbf{k})$, yielding the most probable $\alpha^2F(\omega,\mathbf{k})$ in an automated fashion. This optimisation allows us to discern between bosonic contributions and orbital hybridisation in ARPES spectral functions.
