# Nonlinear Response of a Quantum System to Impulsive Perturbations: A Non-Perturbative Real-Time Approach

@article{Guandalini2020NonlinearRO, title={Nonlinear Response of a Quantum System to Impulsive Perturbations: A Non-Perturbative Real-Time Approach}, author={Alberto Guandalini and Caterina Cocchi and Stefano Pittalis and Alice Ruini and Carlo Andrea Rozzi}, journal={arXiv: Chemical Physics}, year={2020} }

We argue that real-time propagation of quantum states as induced by instantaneous electrical impulses can be an ideal computational tool for investigating nonlinear optical properties of many-electron systems especially when, as in the case of optical limiting, the relevant nonlinearities are not restricted to wave mixing at a predefined order. We demonstrate the capabilities of this methodology through an application to a one-dimensional model system. We show that the Fourier transform of the…

## One Citation

### Understanding real-time time-dependent density-functional theory simulations of ultrafast laser-induced dynamics in organic molecules.

- Physics, ChemistryThe Journal of chemical physics
- 2020

This work analyzes the ultrafast dynamics of three small molecules excited by a resonant laser pulse in the framework of the adiabatic local-density approximation and observes that the laser excitation affects the vibrational spectrum by enhancing the anharmonicities therein, while the coherent vibrational motion contributes to stabilizing the electronic excitation already within a few tens of femtoseconds.

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