Pair-excitation energetics of highly correlated many-body states

TL;DR

This paper introduces a microscopic method to analyze the excitation energies of highly correlated many-body states in semiconductors, predicting a new stable quantum droplet state of electron-hole pairs.

Contribution

It generalizes the Wannier equation to compute excitation energetics from pair correlations, enabling analysis of complex correlated states in semiconductors.

Findings

Verification with Fermi gas and excitons

Prediction of stable quantum droplets of electron-hole pairs

Analysis of energetics and pair-correlation features

Abstract

A microscopic approach is developed to determine the excitation energetics of highly correlated quasi-particles in optically excited semiconductors based entirely on a pair-correlation function input. For this purpose, the Wannier equation is generalized to compute the energy per excited electron-hole pair of a many-body state probed by a weak pair excitation. The scheme is verified for the degenerate Fermi gas and incoherent excitons. In a certain range of experimentally accessible parameters, a new stable quasi-particle state is predicted which consists of four to six electron-hole pairs forming a liquid droplet of fixed radius. The energetics and pair-correlation features of these "quantum droplets" are analyzed.