A tunneling approach for time- and momentum-resolved spectroscopies in correlated materials
In the past years, advances in experiments with X-rays have allowed to probe elementary excitations of correlated materials by means of powerful techniques such as Angle Resolved Emission Spectroscopy (ARPES), X-Ray absorption and emission (XAS/XES) and Resonant Inelastic X-Ray Scattering (RIXS). Nonetheless, unveiling the fundamental aspects of the spectrum remains challenging and, to date, few analytical and numerical tools exist to calculate it with time and momentum resolution. The available ones (e.g. DMFT and exact diagonalization) require the explicit calculation of spectral functions and become prohibitive to large systems. In this talk, we introduce an alternative approach in which the calculation of the spectrum is recast as a tunneling problem that can be readily solved by means of a paralel time-dependent DMRG (tDMRG) implementation. We illustrate how our proposal can be used to obtain the time and resolved spectrum of a Mott insulator after a quench. Then, we ex!
tend this formulation to core-level spectroscopies and obtain the XAS and the RIXS spectra. We show results for the Hubbard model obtained with miminal effort on large systems using a fraction of states - and simulation time - required by dynamical DMRG. Finally, we discuss how our approach can be applied to study complex non-equilibrium and transient dynamics.