Momentum Distribution and Renormalization Factor in Sodium and the Electron Gas

TL;DR

This paper combines experimental x-ray measurements and theoretical calculations to analyze the momentum distribution and quasiparticle renormalization in sodium and the electron gas, confirming the accuracy of quantum Monte Carlo and GW methods.

Contribution

It provides the first detailed comparison of experimental data with advanced many-body calculations for sodium and the electron gas.

Findings

Experimental measurement of the Fermi discontinuity in sodium.

Good agreement between experiment and quantum Monte Carlo and GW calculations.

Validation of theoretical methods for electron correlation in metals.

Abstract

We present experimental and theoretical results on the momentum distribution and the quasiparticle renormalization factor in sodium. From an x-ray Compton-profile measurement of the valence-electron momentum density, we derive its discontinuity at the Fermi wavevector. This yields an accurate measure of the renormalization factor that we compare with quantum Monte Carlo and GW calculations performed both on crystalline sodium and on the homogeneous electron gas. Our calculated results are in good agreement with the experiment.