... Rev. E 71, 046403 (2005) [4] M. Bonitz, D. Block, O. Arp, V. Golubnychiy, H. Baumgartner, P. ... more ... Rev. E 71, 046403 (2005) [4] M. Bonitz, D. Block, O. Arp, V. Golubnychiy, H. Baumgartner, P. Ludwig, A. Piel, and A. Filinov, Phys. Rev. Lett. 96, 075001 (2006) [5] C. Henning, M. Bonitz, A. Piel, P. Ludwig, H. Baumgartner, V. Golubnichiy, and D. Block, submitted to Phys. Rev. E. ...
In a recent Letter [T. Dornheim et al., Phys. Rev. Lett. 117, 156403 (2016)PRLTAO0031-900710.1103... more In a recent Letter [T. Dornheim et al., Phys. Rev. Lett. 117, 156403 (2016)PRLTAO0031-900710.1103/PhysRevLett.117.156403], we presented the first quantum Monte Carlo (QMC) results for the warm dense electron gas in the thermodynamic limit. However, a complete parametrization of the exchange-correlation free energy with respect to density, temperature, and spin polarization remained out of reach due to the absence of (i) accurate QMC results below θ=k_{B}T/E_{F}=0.5 and (ii) QMC results for spin polarizations different from the paramagnetic case. Here we overcome both remaining limitations. By closing the gap to the ground state and by performing extensive QMC simulations for different spin polarizations, we are able to obtain the first completely ab initio exchange-correlation free energy functional; the accuracy achieved is an unprecedented ∼0.3%. This also allows us to quantify the accuracy and systematic errors of various previous approximate functionals.
We perform ab initio quantum Monte Carlo (QMC) simulations of the warm dense uniform electron gas... more We perform ab initio quantum Monte Carlo (QMC) simulations of the warm dense uniform electron gas in the thermodynamic limit. By combining QMC data with the linear response theory, we are able to remove finite-size errors from the potential energy over the substantial parts of the warm dense regime, overcoming the deficiencies of the existing finite-size corrections by Brown et al. [Phys. Rev. Lett. 110, 146405 (2013)]. Extensive new QMC results for up to N=1000 electrons enable us to compute the potential energy V and the exchange-correlation free energy F_{xc} of the macroscopic electron gas with an unprecedented accuracy of |ΔV|/|V|,|ΔF_{xc}|/|F|_{xc}∼10^{-3}. A comparison of our new data to the recent parametrization of F_{xc} by Karasiev et al. [Phys. Rev. Lett. 112, 076403 (2014)] reveals significant deviations to the latter.
Detailed numerical results for the structural properties of three-dimensional classical Coulomb c... more Detailed numerical results for the structural properties of three-dimensional classical Coulomb clusters confined in a spherical parabolic trap are presented. Based on extensive high accuracy computer simulations the shell configurations and energies for particle numbers in the range $2 \le N\le 160$ are reported. Further, the mean shell radii and shell widths are calculated.
A three-dimensional Yukawa liquid exhibits normal self-diffusion which is characterized by Fick&#... more A three-dimensional Yukawa liquid exhibits normal self-diffusion which is characterized by Fick's law and a time-independent diffusion coefficient D [1]. This quantity can be evaluated from the Einstein relation, D=/6t. If however the mean-squared displacement grows faster than linearly with time, the diffusion coefficient is not well defined and the systems exhibits superdiffusive behaviour. Recently, superdiffusion has been observed in two-dimensional Yukawa liquids [2]. In this contribution we enter into the question about the occurrence of superdiffusion in the transiton-region from a purely three-dimensional to a quasi 2D system where one dimension is confined [3,4]. [0pt] [1] H. Ohta and S. Hamaguchi, Phys. Plasmas 7, 4506 (2000) [0pt] [2] B. Liu and J. Goree, Phys. Rev. E 75, 016405 (2007) [0pt] [3] Z. Donk'o, P. Hartmann and G. J. Kalman, Phys. Rev. E 69, 065401 (2004) [0pt] [4] T. Ott, Z. Donk'o, P. Hartmann and M. Bonitz, Submitted to Phys. Rev. E.
The breathing mode is a fundamental normal mode present in Coulomb systems, and may have utility ... more The breathing mode is a fundamental normal mode present in Coulomb systems, and may have utility in identifying particle charge and the Debye length of certain systems. The question remains whether this mode can be extended to strongly coupled Yukawa balls [1]. These systems are characterized by particles confined within a parabolic potential well and interacting through a shielded Coulomb
ABSTRACT Over the last two decades, the Quasi-Localized Charge Approximation (QLCA) has been succ... more ABSTRACT Over the last two decades, the Quasi-Localized Charge Approximation (QLCA) has been successfully applied to investigate the dielectric properties of various strongly coupled systems [1]. While these earlier studies focused on bulk properties, we are concerned with the application of the QLCA to finite inhomogeneous systems. These situations are commonly encountered in ion trap plasmas, ultra-cold neutral plasmas, or dusty plasmas. Starting from the microscopic Lagrangian, we derive an equation for the fluid displacement field and compare our results with previous calculations [2] and a theory for strongly correlated ion plasmas [3]. Since the QLCA accounts for correlation effects, it improves upon so-called ``cold-fluid'' theories and should allow to reduce the discrepancies between the latter and molecular dynamics simulations in a confined Yukawa plasma [4]. Here, we present our first results.[3pt] [1] K. I. Golden and G. J. Kalman, Phys. Plasmas 7, 14 (2000)[0pt] [2] C.-J. Lee and G. J. Kalman, J. Korean Phys. Soc. 58, 448 (2011)[0pt] [3] D. H. E. Dubin and J. P. Schiffer, Phys. Rev. E 53, 5249 (1996), D. H. E. Dubin, Phys. Rev. E 53, 5268 (1996)[0pt] [4] H. K"ahlert and M. Bonitz, Phys. Rev. E 83, 056401 (2011)
Dusty plasmas are a model system for studying strong correlation. The dust grains' size of a few ... more Dusty plasmas are a model system for studying strong correlation. The dust grains' size of a few micro-meters and their characteristic oscillation frequency of a few hertz allows for an investigation of many particle effects on an atomic level. In this article, we model the heat transport through an axially confined 2D dust cluster from the center to the outside. The system behaves particularly interesting since heat is not only conducted within the dust component but also transfered to the neutral gas. Fitting the analytical solution to the obtained radial temperature profiles allows to determine the heat conductivity $\kheat$. The heat conductivity is found to be constant over a wide range of coupling strengths even including the phase transition from solid to liquid here, as it was also found in extended systems by V. Nosenko et al. in 2008 \cite{PhysRevLett.100.025003}
... Rev. E 71, 046403 (2005) [4] M. Bonitz, D. Block, O. Arp, V. Golubnychiy, H. Baumgartner, P. ... more ... Rev. E 71, 046403 (2005) [4] M. Bonitz, D. Block, O. Arp, V. Golubnychiy, H. Baumgartner, P. Ludwig, A. Piel, and A. Filinov, Phys. Rev. Lett. 96, 075001 (2006) [5] C. Henning, M. Bonitz, A. Piel, P. Ludwig, H. Baumgartner, V. Golubnichiy, and D. Block, submitted to Phys. Rev. E. ...
In a recent Letter [T. Dornheim et al., Phys. Rev. Lett. 117, 156403 (2016)PRLTAO0031-900710.1103... more In a recent Letter [T. Dornheim et al., Phys. Rev. Lett. 117, 156403 (2016)PRLTAO0031-900710.1103/PhysRevLett.117.156403], we presented the first quantum Monte Carlo (QMC) results for the warm dense electron gas in the thermodynamic limit. However, a complete parametrization of the exchange-correlation free energy with respect to density, temperature, and spin polarization remained out of reach due to the absence of (i) accurate QMC results below θ=k_{B}T/E_{F}=0.5 and (ii) QMC results for spin polarizations different from the paramagnetic case. Here we overcome both remaining limitations. By closing the gap to the ground state and by performing extensive QMC simulations for different spin polarizations, we are able to obtain the first completely ab initio exchange-correlation free energy functional; the accuracy achieved is an unprecedented ∼0.3%. This also allows us to quantify the accuracy and systematic errors of various previous approximate functionals.
We perform ab initio quantum Monte Carlo (QMC) simulations of the warm dense uniform electron gas... more We perform ab initio quantum Monte Carlo (QMC) simulations of the warm dense uniform electron gas in the thermodynamic limit. By combining QMC data with the linear response theory, we are able to remove finite-size errors from the potential energy over the substantial parts of the warm dense regime, overcoming the deficiencies of the existing finite-size corrections by Brown et al. [Phys. Rev. Lett. 110, 146405 (2013)]. Extensive new QMC results for up to N=1000 electrons enable us to compute the potential energy V and the exchange-correlation free energy F_{xc} of the macroscopic electron gas with an unprecedented accuracy of |ΔV|/|V|,|ΔF_{xc}|/|F|_{xc}∼10^{-3}. A comparison of our new data to the recent parametrization of F_{xc} by Karasiev et al. [Phys. Rev. Lett. 112, 076403 (2014)] reveals significant deviations to the latter.
Detailed numerical results for the structural properties of three-dimensional classical Coulomb c... more Detailed numerical results for the structural properties of three-dimensional classical Coulomb clusters confined in a spherical parabolic trap are presented. Based on extensive high accuracy computer simulations the shell configurations and energies for particle numbers in the range $2 \le N\le 160$ are reported. Further, the mean shell radii and shell widths are calculated.
A three-dimensional Yukawa liquid exhibits normal self-diffusion which is characterized by Fick&#... more A three-dimensional Yukawa liquid exhibits normal self-diffusion which is characterized by Fick's law and a time-independent diffusion coefficient D [1]. This quantity can be evaluated from the Einstein relation, D=/6t. If however the mean-squared displacement grows faster than linearly with time, the diffusion coefficient is not well defined and the systems exhibits superdiffusive behaviour. Recently, superdiffusion has been observed in two-dimensional Yukawa liquids [2]. In this contribution we enter into the question about the occurrence of superdiffusion in the transiton-region from a purely three-dimensional to a quasi 2D system where one dimension is confined [3,4]. [0pt] [1] H. Ohta and S. Hamaguchi, Phys. Plasmas 7, 4506 (2000) [0pt] [2] B. Liu and J. Goree, Phys. Rev. E 75, 016405 (2007) [0pt] [3] Z. Donk'o, P. Hartmann and G. J. Kalman, Phys. Rev. E 69, 065401 (2004) [0pt] [4] T. Ott, Z. Donk'o, P. Hartmann and M. Bonitz, Submitted to Phys. Rev. E.
The breathing mode is a fundamental normal mode present in Coulomb systems, and may have utility ... more The breathing mode is a fundamental normal mode present in Coulomb systems, and may have utility in identifying particle charge and the Debye length of certain systems. The question remains whether this mode can be extended to strongly coupled Yukawa balls [1]. These systems are characterized by particles confined within a parabolic potential well and interacting through a shielded Coulomb
ABSTRACT Over the last two decades, the Quasi-Localized Charge Approximation (QLCA) has been succ... more ABSTRACT Over the last two decades, the Quasi-Localized Charge Approximation (QLCA) has been successfully applied to investigate the dielectric properties of various strongly coupled systems [1]. While these earlier studies focused on bulk properties, we are concerned with the application of the QLCA to finite inhomogeneous systems. These situations are commonly encountered in ion trap plasmas, ultra-cold neutral plasmas, or dusty plasmas. Starting from the microscopic Lagrangian, we derive an equation for the fluid displacement field and compare our results with previous calculations [2] and a theory for strongly correlated ion plasmas [3]. Since the QLCA accounts for correlation effects, it improves upon so-called ``cold-fluid'' theories and should allow to reduce the discrepancies between the latter and molecular dynamics simulations in a confined Yukawa plasma [4]. Here, we present our first results.[3pt] [1] K. I. Golden and G. J. Kalman, Phys. Plasmas 7, 14 (2000)[0pt] [2] C.-J. Lee and G. J. Kalman, J. Korean Phys. Soc. 58, 448 (2011)[0pt] [3] D. H. E. Dubin and J. P. Schiffer, Phys. Rev. E 53, 5249 (1996), D. H. E. Dubin, Phys. Rev. E 53, 5268 (1996)[0pt] [4] H. K"ahlert and M. Bonitz, Phys. Rev. E 83, 056401 (2011)
Dusty plasmas are a model system for studying strong correlation. The dust grains' size of a few ... more Dusty plasmas are a model system for studying strong correlation. The dust grains' size of a few micro-meters and their characteristic oscillation frequency of a few hertz allows for an investigation of many particle effects on an atomic level. In this article, we model the heat transport through an axially confined 2D dust cluster from the center to the outside. The system behaves particularly interesting since heat is not only conducted within the dust component but also transfered to the neutral gas. Fitting the analytical solution to the obtained radial temperature profiles allows to determine the heat conductivity $\kheat$. The heat conductivity is found to be constant over a wide range of coupling strengths even including the phase transition from solid to liquid here, as it was also found in extended systems by V. Nosenko et al. in 2008 \cite{PhysRevLett.100.025003}
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