Reply to comment of Shukla et al. on 'On "Novel attractive forces" between ions in quantum plasmas - failure of linearized quantum hydrodynamics'

TL;DR

This paper refutes claims that density functional theory (DFT) is unsuitable for benchmarking quantum plasma models, demonstrating that previous results showing the failure of linearized quantum hydrodynamics are valid and reliable.

Contribution

The authors clarify the limitations of quantum hydrodynamics and defend DFT as a proper benchmark, countering claims that DFT is inadequate for analyzing dense plasma interactions.

Findings

DFT accurately benchmarks quantum plasma models

LQHD's failure to predict attractive forces is validated

DFT's limitations are well-understood and appropriate for comparison

Abstract

In an earlier paper we demonstrated that the "novel attractive force" between protons in dense hydrogen reported by Shukla and Eliasson based on linearized quantum hydrodynamics (LQHD) is wrong. As benchmark results we used state of the art density functional theory (DFT) simulations. In their response to that paper Shukla et al. (arXiv:1112.5556) claimed that the disagreement is due to a failure of DFT. Here we show - by comparing the properties and limitations of DFT and QHD - that their statements have no scientific basis and that DFT is a suitable benchmark for more approximate approaches such as QHD and LQHD.