Multiscale Modeling of Matter under Extreme Conditions



Otto-Müller-Str. 3, 02826 Görlitz
Attila Cangi (Center for Advanced Systems Understanding, HZDR), Aurora Pribram-Jones (University of California, Merced)

This workshop brings together experts from the spectrum of available modeling techniques relevant to matter under extreme conditions. The goal is to summarize the state of the art, identify the current caveats of each methodology, and devise strategies on achieving multiscale workflows. 

Registration and Abstract Submission
Program Committee
    • Registration
    • 1
      Welcome by Program Committee
    • Morning Session (Monday)

      Session Chair: TBD

      • 2
        Dominik Kraus (University of Rostock, Germany)
      • 3
        Tobias Dornheim (CASUS, Helmholtz-Zentrum Dresden-Rossendorf, Germany)
      • 10:30 AM
        Coffee Break
      • 4
        Contributed Talk 1
      • 5
        Michael Bonitz (Kiel University, Germany)
    • 12:15 PM
      Lunch Break
    • Afternoon Session (Monday)

      Session Chair: TBD

      • 6
        Brenda Rubinstein (Brown University, United States)
      • 7
        Contributed Talk 2
      • 3:45 PM
        Coffee Break
      • 8
        Aurora Pribram-Jones (University of California, Merced, United States)
      • 9
        Contributed Talk 3
    • Morning Session (Tuesday)

      Session Chair: TBD

      • 10
        Ulf Zastrau (European XFEL, Germany)
      • 11
        Invited Talk (DFT-MD)
      • 10:30 AM
        Coffee Break
      • 12
        Contributed Talk 4
      • 13
        Electronic transport properties of matter under extreme conditions from density functional theory

        The determination of thermoelectric transport coefficients of dense, partially ionized matter is a great challenge for both experiment and theory. In the past two decades, density functional theory (DFT) has evolved to an efficient tool for making theoretical predictions of properties of matter under extreme conditions. Many of these are of high relevance for modelling the interior states, evolution, and magnetic field dynamics of stellar and planetary objects. Here I will give an overview on the generalized Kubo-Greenwood (KG) formalism [1] that is frequently used in calculations of electronic transport properties using the Kohn-Sham states from DFT. Several examples of successful application of this technique to various solid and fluid metals will be presented. Furthermore, a comparison of optical reflectivities of molecular fluids observed in dynamic compression experiments [2] will be made, including a discussion of the influence of the exchange-correlation functional on the DFT results. Finally, the limitations of the KG formalism with respect to its capability of describing electron-electron collisions will be discussed by examining the thermopower and Lorenz number of weakly degenerate hydrogen plasmas. It is shown [3] that the DFT results approach the limiting values for a Lorentz plasma, which is a model system that only considers electron-ion collisions, instead of agreeing with the Spitzer results [4], which were derived taking both electron-ion and electron-electron scattering into account. These recent findings [3] are of substantial importance for future methodical developments to calculate transport properties of matter under extreme conditions and, especially, for correctly assessing the results obtained via the Kubo-Greenwood formalism in relation to experiments and other theoretical approaches. This work is supported by the DFG within the FOR 2440 "Matter under Planetary Interior Conditions - High Pressure, Planetary, and Plasma Physics."

        [1] B. Holst, M. French, and R. Redmer, "Electronic transport coefficients from ab initio simulations and application to dense liquid hydrogen", Phys. Rev. B 83, 235120 (2011).
        [2] A. Ravasio, M. Bethkenhagen, J.-A. Hernandez, A. Benuzzi-Mounaix, F. Datchi, M. French, M. Guarguaglini, F. Lefevre, S. Ninet, R. Redmer, and T. Vinci, "Metallization of Shock-Compressed Liquid Ammonia", Phys. Rev. Lett. 126, 025003 (2021).
        [3] M. French, G. Röpke, M. Schörner, M. Bethkenhagen, M. P. Desjarlais, and R. Redmer, "Electronic transport coefficients from density functional theory across the plasma plane", Phys. Rev. E 105, 065204 (2022).
        [4] L. Spitzer, Jr. and R. Härm, "Transport Phenomena in a Completely Ionized Gas", Phys. Rev. 89, 977 (1953).

        Speaker: Martin French (University of Rostock, Germany)
    • 12:15 PM
      Lunch Break
    • Afternoon Session (Tuesday)

      Session Chair: TBD

      • 14
        Average-atom-type models for warm dense matter

        Material properties of warm dense matter, like equation of state and conductivity, are needed for modeling stars, fusion plasmas, and high-energy-density experiments. Since the beginning of this field, average atom models have been used to provide such data. In this talk, I will give an abridged introduction, historical perspective, and review of modern average atom models and methods. I will highlight their strengths and discuss recent approaches to improvements on both the physical model and numerical stability.

        Speaker: Charles Starrett (Los Alamos National Laboratory, United States)
      • 15
        Contributed Talk 5
      • 3:45 PM
        Coffee Break
      • 16
        Aidan Thompson (Sandia National Laboratories, United States)
      • 17
        Contributed Talk 6
    • 18
      Poster Session
    • Morning Session (Wednesday)

      Session Chair: TBD

      • 19
        Katerina Falk (Helmholtz-Zentrum Dresden-Rossendorf, Germany)
      • 20
        Julien Tranchida (French Alternative Energies and Atomic Energy Commission, France)
      • 10:30 AM
        Coffee Break
      • 21
        Contributed Talk 7
      • 22
        Hardy Gross (Hebrew University of Jerusalem, Israel)
    • 12:15 PM
      Lunch Break
    • Afternoon Session (Wednesday)

      Session Chair: TBD

      • 23
        Andrew Baczewski (Sandia National Laboratories, United States)
      • 24
        Contributed Talk 8
      • 3:45 PM
        Coffee Break
    • 4:15 PM
      City Tour / Free afternoon
    • 7:00 PM
      Conference Dinner
    • Morning Session (Thursday)

      Session Chair: TBD

      • 25
        Beata Ziaja-Motyka (Deutsches Elektronen Synchrotron, Germany)
      • 26
        Conditional probability DFT and warm dense matter

        Recently, our group suggested an alternative approach to standard DFT calculations. In CP-DFT, we use Kohn-Sham calculations to find conditional probability densities at every point in a system. These are then integrated to yield the exchange-correlation energy, thereby avoiding the need (and many of the failures) to find the energy via an approximate functional. We found that we could reproduce (reasonably accurately) the uniform gas ground-state energy and free energy as a function of temperature, as well as having no self-interaction error for one-electron systems, and being able to correctly dissociate the H2 molecule. I will summarize our progress toward using this to generate the temperature dependence of PBE.

        [1] Bypassing the Energy Functional in Density Functional Theory: Direct Calculation of Electronic Energies from Conditional Probability Densities Ryan J. McCarty, Dennis Perchak, Ryan Pederson, Robert Evans, Yiheng Qiu, Steven R. White, and Kieron Burke, Phys. Rev. Lett. 125, 266401 (2020).
        [2] Correlation energy of the uniform gas determined by ground state conditional probability density functional theory Dennis Perchak, Ryan J. McCarty, and Kieron Burke, Phys. Rev. B 105, 165143 (2022).
        [3] Conditional probability density functional theory Ryan Pederson, Jielun Chen, Steven R. White, and Kieron Burke, to appear in Phys Rev B (2022).

        Speaker: Kieron Burke (University of California, Irvine, United States)
      • 10:30 AM
        Coffee Break
      • 27
        Thermal PBE for Warm Dense Matter Calculations

        Finite-Temperature Density Functional Theory (FT-DFT) has played a significant role in the study of warm dense matter over the past few decades. However, modern FT-DFT calculations typically make use of ground-state approximations to the exchange-correlation (XC) free energy, ignoring its temperature dependence. While overall the ground-state approximation is valid in both the low- and high-temperature limits, the quantitative ramifications of this approximation are unknown and may be crucial to our current understanding of warm dense matter. To correct this, we calculate the temperature dependence of PBE through a sequence of Kohn-Sham CP-DFT calculations [1] that yield accurate exchange-correlation holes at finite temperatures. We will present the results of this thermal PBE and compare with existing suggestions in the literature.

        [1] R. J. McCarty, et al. “Bypassing the Energy Functional in Density Functional Theory: Direct Calculation of Electronic Energies from Conditional Probability Densities.” Phys. Rev. Lett. 125, 266401 (2020).

        We acknowledge funding from the Department of Energy Award No. DE-FG02-08ER46496.

        Speaker: John Kozlowski (University of California, Irvine, United States)
      • 28
        Nico Hoffmann (Helmholtz-Zentrum Dresden-Rossendorf, Germany)
    • 12:15 PM
      Lunch Break
    • Afternoon Session (Thursday)

      Session Chair: TBD

      • 29
        Siva Rajamanickam (Sandia National Laboratories, United States)
      • 30
        Contributed Talk 10
      • 3:45 PM
        Coffee Break
      • 31
        Attila Cangi (CASUS, Helmholtz-Zentrum Dresden-Rossendorf, Germany)
      • 32
        Contributed Talk 11
    • Morning Session (Friday)

      Session Chair: TBD

      • 33
        Frank Graziani (Lawrence Livermore National Laboratory, United States)
      • 34
        Kay Dewhurst (Max Planck Institute of Microstructure Physics, Germany)
      • 10:30 AM
        Coffee Break
      • 35
        Contributed Talk 12
      • 36
        Alexander Debus (Helmholtz-Zentrum Dresden-Rossendorf, Germany)
    • 37
      Closing Remarks