# Spectroscopic Properties of Polarons in Strongly Correlated Systems by Exact Diagrammatic Monte Carlo Method

## TL;DR

This paper introduces advanced Diagrammatic Monte Carlo methods for accurately studying the spectral and dynamical properties of polarons and related strongly correlated electron-phonon systems, providing unbiased results.

## Contribution

It develops novel, approximation-free Monte Carlo techniques for calculating Green functions and spectral functions in complex electron-phonon coupled systems.

## Key findings

- Exact ground state properties of various polarons obtained.
- Spectral functions and optical conductivities computed without bias.
- Results applicable to multiple strongly correlated models.

## Abstract

We present recent advances in understanding of the ground and excited states of the electron-phonon coupled systems obtained by novel methods of Diagrammatic Monte Carlo and Stochastic Optimization, which enable the approximation-free calculation of Matsubara Green function in imaginary times and perform unbiased analytic continuation to real frequencies. We present exact numeric results on the ground state properties, Lehmann spectral function and optical conductivity of different strongly correlated systems: Frohlich polaron, Rashba-Pekar exciton-polaron, pseudo Jahn-Teller polaron, exciton, and interacting with phonons hole in the t-J model.