Chebyshev-expanded covariant density functional from relativistic Brueckner theory
Abstract
We construct a density-dependent covariant energy density functional (CE-ME1) from full-Dirac-space relativistic Brueckner--Hartree--Fock (RBHF) self-energies and the corresponding equation of state. The space-like component UV is incorporated at the Fermi surface through reduced scalar and time-like self-energies, which are mapped onto local Hartree σ, ω, δ, and ρ channels. The density-dependent couplings are represented by cubic Chebyshev polynomials over the density range 0.08≤ρ≤0.48 fm−3. A constrained thermodynamic calibration uses 199 RBHF energy-per-particle values from published microscopic computations at six isospin asymmetries, while maintaining positive, monotonic couplings. The Bonn-A RBHF saturation point, incompressibility K∞=258 MeV, symmetry energy J=33.1 MeV, and slope L=65.2 MeV are reproduced. The predicted curvature Ksym=33 MeV differs from the published RBHF value of −67 MeV, illustrating the derivative sensitivity of the local reduction. The combined energy RMS is $0.613$ MeV, measuring model discrepancy rather than statistical uncertainty. Uniform matter remains mechanically stable and causal above saturation within the calibrated range. In cold charge-neutral npeμ matter, CE-ME1 reasonably reproduces the interpolated RBHF pressure and proton fraction over most of the interval, although the pressure discrepancy increases near its upper edge. The DD-ME2 benchmark is stiffer and predicts a lower proton fraction at high density.
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BibTeX
@misc{sedrakian2026chebyshevexpanded,
title = {{Chebyshev-expanded covariant density functional from relativistic Brueckner theory}},
author = {Armen Sedrakian},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.36299},
eprint = {2610.36299},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.36299},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Chebyshev-expanded covariant density functional from relativistic Brueckner theory
AU - Armen Sedrakian
PY - 2026
DA - 2026/10/26
PB - arXiv
DO - 10.48550/arxiv.2610.36299
UR - https://arxiv.org/abs/2610.36299
AB - We construct a density-dependent covariant energy density functional (CE-ME1) from full-Dirac-space relativistic Brueckner--Hartree--Fock (RBHF) self-energies and the corresponding equation of state. The space-like component U_V is incorporated at the Fermi surface through reduced scalar and time-like self-energies, which are mapped onto local Hartree σ, ω, δ, and ρ channels. The density-dependent couplings are represented by cubic Chebyshev polynomials over the density range 0.08≤ρ≤0.48 fm^−3. A constrained thermodynamic calibration uses 199 RBHF energy-per-particle values from published microscopic computations at six isospin asymmetries, while maintaining positive, monotonic couplings. The Bonn-A RBHF saturation point, incompressibility K_∞=258 MeV, symmetry energy J=33.1 MeV, and slope L=65.2 MeV are reproduced. The predicted curvature K_sym=33 MeV differs from the published RBHF value of −67 MeV, illustrating the derivative sensitivity of the local reduction. The combined energy RMS is $0.613$ MeV, measuring model discrepancy rather than statistical uncertainty. Uniform matter remains mechanically stable and causal above saturation within the calibrated range. In cold charge-neutral npeμ matter, CE-ME1 reasonably reproduces the interpolated RBHF pressure and proton fraction over most of the interval, although the pressure discrepancy increases near its upper edge. The DD-ME2 benchmark is stiffer and predicts a lower proton fraction at high density.
ER -