Temperature dependence of spectral functions for the one-dimensional Hubbard model: comparison with experiments

TL;DR

This study investigates how temperature affects spectral functions in the one-dimensional Hubbard model using quantum Monte Carlo simulations, comparing results with experimental data from TTF-TCNQ to understand spectral weight transfer and magnetic fluctuations.

Contribution

It provides a detailed analysis of temperature-dependent spectral functions in the 1D Hubbard model and compares theoretical results with experimental photoemission data.

Findings

Spectral functions show features of the ground state for T < T_J.

Spectral weight transfer occurs over a scale set by hopping t above T_J.

Discrepancies between model calculations and experiments are discussed.

Abstract

We study the temperature dependence of the single particle spectral function as well as of the dynamical spin and charge structure factors for the one-dimensional Hubbard model using the finite temperature auxiliary field quantum Monte Carlo algorithm. The parameters of our simulations are chosen so to at best describe the low temperature photoemission spectra of the organic conductor TTF-TCNQ. Defining a magnetic energy scale, T_J, which marks the onset of short ranged 2k_f magnetic fluctuations, we conclude that for temperatures T < T_J the ground state features of the single particle spectral function are apparent in the finite temperature data. Above T_J spectral weight transfer over a scale set by the hopping t is observed. In contrast, photoemission data points to a lower energy scale below which spectral weight transfer occurs. Discrepancies between Hubbard model calculations and experiments are discussed.