**A time-dependent scattering approach to core-level spectroscopies.** / Zawadzki, Krissia; Nocera, Alberto; Feiguin, Adrian E.

Research output: Working paper › Preprint

Published

**A time-dependent scattering approach to core-level spectroscopies.** / Zawadzki, Krissia; Nocera, Alberto; Feiguin, Adrian E.

Research output: Working paper › Preprint

Zawadzki, K, Nocera, A & Feiguin, AE 2020 'A time-dependent scattering approach to core-level spectroscopies'.

Zawadzki, K., Nocera, A., & Feiguin, A. E. (2020). *A time-dependent scattering approach to core-level spectroscopies*.

Zawadzki K, Nocera A, Feiguin AE. A time-dependent scattering approach to core-level spectroscopies. 2020 Feb 11.

@techreport{e651bcd49fbc415c9119ffc1c0925a89,

title = "A time-dependent scattering approach to core-level spectroscopies",

abstract = " While new light sources allow for unprecedented resolution in experiments with X-rays, a theoretical understanding of the scattering cross-section lacks closure. In the particular case of strongly correlated electron systems, numerical techniques are quite limited, since conventional approaches rely on calculating a response function (Kramers-Heisenberg formula) that is obtained from a time-dependent perturbative analysis of scattering processes. This requires a knowledge of a full set of eigenstates in order to account for all intermediate processes away from equilibrium, limiting the applicability to small tractable systems. In this work, we present an alternative paradigm allowing to explicitly solving the time-dependent Schr\{"}odinger equation without the limitations of perturbation theory, a faithful simulation of all scattering processes taking place in actual experiments. We introduce the formalism and an application to Mott insulating Hubbard chains using the time-dependent density matrix renormalization group method, which does not require a priory knowledge of the eigenstates and thus, can be applied to very large systems with dozens of orbitals. Away from the ultra short lifetime limit we find signatures of spectral weight at low energies that can be explained in terms of gapless multi-spinon excitations. Our approach can readily be applied to systems out of equilibrium without modification. ",

keywords = "cond-mat.str-el",

author = "Krissia Zawadzki and Alberto Nocera and Feiguin, {Adrian E.}",

year = "2020",

month = feb,

day = "11",

language = "Undefined/Unknown",

type = "WorkingPaper",

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TY - UNPB

T1 - A time-dependent scattering approach to core-level spectroscopies

AU - Zawadzki, Krissia

AU - Nocera, Alberto

AU - Feiguin, Adrian E.

PY - 2020/2/11

Y1 - 2020/2/11

N2 - While new light sources allow for unprecedented resolution in experiments with X-rays, a theoretical understanding of the scattering cross-section lacks closure. In the particular case of strongly correlated electron systems, numerical techniques are quite limited, since conventional approaches rely on calculating a response function (Kramers-Heisenberg formula) that is obtained from a time-dependent perturbative analysis of scattering processes. This requires a knowledge of a full set of eigenstates in order to account for all intermediate processes away from equilibrium, limiting the applicability to small tractable systems. In this work, we present an alternative paradigm allowing to explicitly solving the time-dependent Schr\"odinger equation without the limitations of perturbation theory, a faithful simulation of all scattering processes taking place in actual experiments. We introduce the formalism and an application to Mott insulating Hubbard chains using the time-dependent density matrix renormalization group method, which does not require a priory knowledge of the eigenstates and thus, can be applied to very large systems with dozens of orbitals. Away from the ultra short lifetime limit we find signatures of spectral weight at low energies that can be explained in terms of gapless multi-spinon excitations. Our approach can readily be applied to systems out of equilibrium without modification.

AB - While new light sources allow for unprecedented resolution in experiments with X-rays, a theoretical understanding of the scattering cross-section lacks closure. In the particular case of strongly correlated electron systems, numerical techniques are quite limited, since conventional approaches rely on calculating a response function (Kramers-Heisenberg formula) that is obtained from a time-dependent perturbative analysis of scattering processes. This requires a knowledge of a full set of eigenstates in order to account for all intermediate processes away from equilibrium, limiting the applicability to small tractable systems. In this work, we present an alternative paradigm allowing to explicitly solving the time-dependent Schr\"odinger equation without the limitations of perturbation theory, a faithful simulation of all scattering processes taking place in actual experiments. We introduce the formalism and an application to Mott insulating Hubbard chains using the time-dependent density matrix renormalization group method, which does not require a priory knowledge of the eigenstates and thus, can be applied to very large systems with dozens of orbitals. Away from the ultra short lifetime limit we find signatures of spectral weight at low energies that can be explained in terms of gapless multi-spinon excitations. Our approach can readily be applied to systems out of equilibrium without modification.

KW - cond-mat.str-el

M3 - Preprint

BT - A time-dependent scattering approach to core-level spectroscopies

ER -