Charge Transport Properties of Matter Under Extreme Conditions from ab initio Molecular Dynamics

Warm dense matter (WDM), believed to constitute the cores of giant icy planetary and stellar systems, has been an entity of long-standing interest due to its realization in inertial confinement fusion experiments in a controlled laboratory environment. A quantum mechanical description of this exotic state of matter is crucial for guiding experimental efforts into probing this regime as well as verifying the equation of state and other transport properties typically obtained from analytical models. Recently, density functional theory (DFT) and its time-dependent extension (TDDFT) have emerged as powerful tools for modeling the static and dynamic transport properties of such hot dense systems. In the traditional formulation of DFT, its computational complexity scales cubically with system size and temperature, making it computationally rather expensive. In this talk, I will describe an alternative linear-scaling approach that applies stochastic techniques to the traditional Kohn-Sham DFT framework. Further, I will discuss a novel proposal for a mixed DFT (mDFT) formalism that combines the stochastic and deterministic Kohn-Sham algorithms to study matter at moderate to very high temperatures [1]. Finally, I will highlight targeted physical observables, diffusivity, and conductivities obtained in a computationally efficient fashion within this formalism for multiple testbed WDM single-component systems and mixtures [2].

[1] Sharma, V., Collins, L.A., and White, A.J., "Stochastic and mixed density functional theory within the projector augmented wave formalism for simulation of warm dense matter,'' Phys. Rev. E., 2023, 108, L023201.

[2] Sharma, V., Collins, L.A., and White, A.J., "Charge transport in matter under extreme physical conditions from accelerated ab initio molecular dynamics," [in preparation].