Thermodynamic and dynamic properties of warm dense hydrogen revisited*

.Accurate knowledge of the properties of hydrogen at high compression are crucial for astrophysics and laboratory experiments, including inertial confinement fusion. Today there exist extensive collections of data originating from  path integral Monte Carlo (PIMC) simulations [1, 2], DFT, chemical models and combinations thereof [3]. However, each of these methods has severe limitations rendering the accuracy of the hydrogen data unclear. This has become particularly evident when the first exact PIMC simulation results for the model of the uniform electron gas (UEG) became available [4] which revealed surprising deviations of restricted PIMC results. In the mean time extensive thermodynamic data for the UEG have been reported [5], and the simulations have been extended to dynamic properties, including the the dynamic structure factor [6]. Here, we present an overview on the application of our improved PIMC simulations [5] to partially ionized warm dense hydrogen, taking advantage of a further improvement originating from a transition to the grand ensemble [7]. The thermodynamic results allow us to benchmark earlier simulations and models and make reliable predictions for experiments. Moreover we present data for the momentum distribution. Finally, the roton-type minimum of the plasmon dispersion that was previously reported for the UEG [6,8], is confirmed for hydrogen as well and parameters for an experimental observation are presented [9].

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[9] P. Hamann. L. Kordts, A. Filinov, M. Bonitz, T. Dornheim, and J. Vorberger, PRR (2023), arXiv: 2304.10807