First-principles, spatially- and temporally-nonlocal exchange-correlation kernel for jellium at all densities

Accurate parameterizations of the ground-state exchange-correlation energy of jellium have been known since Quantum Monte Carlo calculations in the 1980s. However, an equally accurate description of the time-dependent linear response of an electron gas to an external perturbation has been elusive. Many extant models of the jellium exchange-correlation kernel have substantial limitations: restrictions on the range of densities for which the model is accurate, restrictions to purely real or purely imaginary frequencies, etc. In this talk, I’ll motivate and describe a refinement [a] of the MCP07 [b] kernel that modifies its wavevector and frequency dependence, yielding a kernel that extrapolates to a very wide range of densities. The model kernel makes substantial corrections at low densities, where MCP07 is known to be least accurate, and fine tunes MCP07’s already excellent accuracy at typical metallic densities.  Moreover, our model is numerically parameterized at all real and purely imaginary frequencies, a boon to further computational and theoretical applications. Excited-state phenomena predicted with our model will also be discussed.

[a] A.D. Kaplan, N.K. Nepal, A. Ruzsinszky, P. Ballone, and J.P. Perdew, arXiv:2107.02249 (2021) (submitted).

[b] A. Ruzsinszky, N.K. Nepal, J.M. Pitarke, and J.P. Perdew, Phys. Rev. B 101, 245135 (2020).