Non-perturbative series expansion of Green's functions: The Anatomy of Resonant Inelastic X-Ray Scattering in Doped Hubbard Model

Abstract

We present a non-perturbative, divergence-free series expansion of Green's functions using effective operators. The method is especially suited for computing correlators of complex operators as a series of correlation functions of simpler forms. We apply the method to study low-energy excitations in resonant inelastic x-ray scattering (RIXS) in doped one- and two-dimensional single-band Hubbard models. The RIXS operator is expanded into polynomials of spin, density, and current operators weighted by fundamental x-ray spectral functions. These operators couple to different polarization channels resulting in simple selection rules. The incident photon energy dependent coefficients help to pinpoint main RIXS contributions from different degrees of freedom. We show in particular that, with parameters pertaining to cuprate superconductors, local spin excitation dominates the RIXS spectral weight over a wide doping range in the cross-polarization channel.

arXiv comment6+6 pages; 4+9 figures

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Cited by in corpus (9)

• Exploring Quantum Materials with Resonant Inelastic X-Ray Scattering
• Quantum Many-Body Effects in X-Ray Spectra Efficiently Computed using a Basic Graph Algorithm
• Dynamical spin susceptibility in La2CuO4 studied by resonant inelastic x-ray scattering
• Description of resonant inelastic x-ray scattering in correlated metals
• Unraveling higher-order corrections in the spin dynamics of RIXS spectra
• Taming Convergence in the Determinant Approach for X-Ray Excitation Spectra
• Theory of electron-phonon interactions in extended correlated systems probed by resonant inelastic x-ray scattering
• Polarization dependency in Resonant Inelastic X-Ray Scattering
• Nonequilibrium Dynamics in a Quantum Spin Chain with Pump-Probe Resonant Inelastic X-ray Scattering