Evidence of attraction between charge-carriers in a doped Mott insulator

TL;DR

This paper uses advanced Monte Carlo simulations to provide unbiased evidence of charge-carrier attraction in doped Mott insulators at low temperatures, relevant for understanding high-temperature superconductivity.

Contribution

It introduces a worm-algorithm Monte Carlo method to study charge carriers in Mott insulators at low temperatures, overcoming the sign problem.

Findings

Evidence of attraction between dopants at accessible low temperatures.

Provides spin-correlation data comparable to ultracold atomic experiments.

Accesses temperature regimes previously unreachable in simulations.

Abstract

Recent progress in optically trapped ultracold atomic gases is now making it possible to access microscopic observables in doped Mott insulators, which are the parent states of high-temperature superconductors. This makes it possible to address longstanding questions about the temperature scales at which attraction between charge carriers are present, and their mechanism. Controllable theoretical results for this problem are not available at low temperature due to the sign problem. In this work, we employ worm-algorithm Monte Carlo to obtain completely unbiased results for two charge carriers in a Mott insulator. Our method gives access to lower temperatures than what is currently possible in experiments, and provides evidence for attraction between dopants at a temperature scale that is now feasible in ultracold atomic systems. We also report on spin-correlations in the presence of charge carriers, which are directly comparable to experiments.