Second roton feature in the strongly coupled electron liquid

2025/05/16 by Thomas Chuna, Jan Vorberger, Chuna, Thomas M. +13 · 8 citations
Physics and Astronomy · #Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Quantum Gases (cond-mat.quant-gas) #Quantum and electron transport phenomena #Quantum, superfluid, helium dynamics #Strongly Correlated Electrons (cond-mat.str-el)

paper · pdf · doi:10.48550/arxiv.2505.11150

openalex publication_date 2025/05/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We present extensive ab initio path integral Monte Carlo (PIMC) results for the dynamic properties of the finite temperature uniform electron gas (UEG) over a broad range of densities, 2≤ r_s≤300. We demonstrate that the direct analysis of the imaginary-time density--density correlation function (ITCF) allows for a rigorous assessment of the density and temperature dependence of the previously reported roton-type feature [T.~Dornheim, Phys.~Rev.~Lett.~121, 255001 (2018)] at intermediate wavenumbers. We clearly resolve the emergence of a second roton at the second harmonic of the original feature for r_s\gtrsim100, which we identify as an incipient phonon dispersion. Finally, we use our highly accurate PIMC results for the ITCF as the basis for an analytic continuation to compute the dynamic structure factor, which additionally substantiates the existence of the second roton in the strongly coupled electron liquid. Our investigation further elucidates the complex interplay between quantum delocalization and Coulomb coupling in the UEG. All PIMC results are freely available online and provide valuable benchmarks for other theoretical methodologies and approximations.

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Related

• Estimates of the dynamic structure factor for the finite temperature electron liquid via analytic continuation of path integral Monte Carlo data
• Dynamic exchange-correlation effects in the strongly coupled electron liquid
• Electronic pair alignment and roton feature in the warm dense electron gas
• Physical insights from imaginary-time density--density correlation functions
• Quantum delocalization, structural order, and density response of the strongly coupled electron liquid