262 citations · 4.3k across the 149 of their papers we have counts for
155 papers
The quadratic density response function for non-interacting fermions at arbitrary temperature
Pontus Svensson, Jan Vorberger, Zhandos A. Moldabekov +5
We develop and implement the quadratic density response function of non-interacting fermions at arbitrary temperature, frequencies, and wave vectors. Starting from a Green's functi…
Analysis of the Ill-Conditioning of the Discrete Inverse Laplace transform in Monte Carlo Simulations of Quantum Many-Body Systems
Phil-Alexander Hofmann, Thomas Chuna, Tobias Dornheim +1
Analytic continuation of imaginary-time quantum Monte Carlo data to real-frequency spectra requires the inversion of a severely ill-posed two-sided Laplace transform and arises nat…
Reconciling chemical models of X-ray Thomson Scattering with the Bethe -sum rule
Maximilian P. Böhme, Paul Hamann, Veronika A. Kruse +9
X-ray Thomson scattering (XRTS) is a key diagnostic for high-energy-density plasmas, which can exhibit significant quantum effects even at elevated temperatures. XRTS experiments a…
Ab initio path integral Monte Carlo study of the 2D uniform electron liquid at finite temperatures
Tobias Dornheim, Fotios Kalkavouras, Paul Hamann +3
We present extensive \emph{ab initio} path integral Monte Carlo (PIMC) simulations of the two-dimensional uniform electron gas (2DEG), covering a broad range of density parameters…
Kinetic energy from the cubic sum rule of the dynamic structure factor
Fotios Kalkavouras, Panagiotis Tolias, Sebastian Schwalbe +6
The third frequency moment sum rule of the dynamic structure factor is explored for the first time as an alternative estimator of the kinetic energy of quantu…
Discovering a well-conditioned analytic continuation problem via dictionary learning
Thomas Chuna, Phil-Alexander Hofmann, Alexander Benedix-Robles +1
Many fields of physics use quantum Monte Carlo (QMC) simulations to simulate quantum systems in imaginary-time and estimate imaginary-time correlation functions (ITCF). However…
Thermal PBE in warm dense matter: Does it matter and is it accurate?
Kushal Ramakrishna, Mani Lokamani, Zhandos A. Moldabekov +3
Conditional probability density functional theory has recently been used to derive the temperature dependence of the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation…
Reweighting Estimators for Density Response in Path Integral Monte Carlo: Applications to linear, nonlinear and cross-species density response
Pontus Svensson, Thomas Chuna, Jan Vorberger +5
We present density response estimators for Monte Carlo simulations that are based on a reweighting procedure, where the samples of an unperturbed system are used to estimate the pr…
Overview of X-ray Thomson scattering measurements of extreme states of matter
Tobias Dornheim, Hannah Bellenbaum, Thomas Gawne +2
Since its first successful applications in the early 2000s, x-ray Thomson scattering (XRTS) has emerged as one of the most successful tools for the diagnostics of extreme states of…
Monte-Carlo Event Generation for X-Ray Thomson Scattering Analysis
Uwe Hernandez Acosta, Thomas Gawne, Jan Vorberger +6
A key diagnostic in warm-dense matter (WDM) experiments is X-ray Thomson scattering (XRTS), but its interpretation is often limited by complex instrument effects and the high compu…
Mermin's dielectric function and the f-sum rule
Thomas Chuna, Jan Vorberger, Thomas Gawne +2
Mermin's dielectric function [N.D. Mermin, Phys. Rev. B 1, 2362 (1970)] is widely assumed to satisfy the f-sum rule because he constrains his ansatz with the continuity equation. H…
Unlocking the Power of Orbital-Free Density Functional Theory to Explore the Electronic Structure Under Extreme Conditions
Cheng Ma, Qiang Xu, Zhenhao Zhang +8
Recent advances in X-ray free-electron laser diagnostics have enabled direct probing of the electronic structure under extreme pressures and temperatures, such as those encountered…
Ab initio path-integral Monte Carlo results for the one-particle spectral function of the warm dense electron gas
Paul Hamann, Michael Bonitz, Jan Vorberger +1
We present quasi-exact \emph{ab initio} path-integral Monte Carlo results for the Matsubara Green's function of the uniform electron gas (UEG) at finite temperature over a broad ra…
XFEL Imaging Techniques for High Energy Density and Inertial Fusion Energy Research at HED-HiBEF
Alejandro Laso Garcia, Mikhail Mishchenko, Victorien Bouffetier +53
The imaging platform developed at the High Energy Density - Helmholtz International Beamline for Extreme Fields (HED-HiBEF) instrument at the European XFEL and its applications to…
Dielectric formalism of the 2D uniform electron gas at finite temperatures
Fotios Kalkavouras, Tobias Dornheim, Paul Hamann +1
We present a comprehensive analysis of the two-dimensional uniform electron gas (2D-UEG or more commonly 2DEG) at finite temperature, spanning a broad range of densities / coupling…
Generalized density functional theory framework for the non-linear density response of quantum many-body systems
Zhandos A. Moldabekov, Cheng Ma, Xuecheng Shao +5
A density functional theory (DFT) framework is presented that links functional derivatives of free-energy functionals to non-linear static density response functions in quantum man…
The noiseless limit and improved-prior limit of the maximum entropy method and their implications for the analytic continuation problem
Thomas Chuna, Nicholas Barnfield, Paul Hamann +3
Quantum Monte Carlo (QMC) methods are uniquely capable of providing exact simulations of quantum many-body systems. Unfortunately, the applications of a QMC simulation are limited…
Van-der-Waals exchange-correlation functionals and their high pressure and warm dense matter applications
Jan Vorberger, Gabriel J. Smith, William Z. Van Benschoten +4
We investigate basic hydrogen quantities like the molecular bond length, the molecular dissociation energy and the van-der-Waals interaction in idealized situations in an effort to…
Spectral Deconvolution without the Deconvolution: Extracting Temperature from X-ray Thomson Scattering Spectra without the Source-and-Instrument Function
Thomas Gawne, Alina Kononov, Andrew Baczewski +7
X-ray Thomson scattering (XRTS) probes the dynamic structure factor of the system, but the measured spectrum is broadened by the combined source-and-instrument function (SIF) of th…
Enhancing the Efficiency of Time-Dependent Density Functional Theory Calculations of Dynamic Response Properties
Zhandos A. Moldabekov, Sebastian Schwalbe, Uwe Hernandez Acosta +4
X-ray Thomson scattering (XRTS) constitutes an essential technique for diagnosing material properties under extreme conditions, such as high pressures and intense laser heating. Ti…
Correlation function metrology for warm dense matter: Recent developments and practical guidelines
Maximilian Peter Böhme, Willow Martin, Hannah Bellenbaum +13
X-ray Thomson scattering (XRTS) has emerged as a valuable diagnostic for matter under extreme conditions, as it captures the intricate many-body physics of the probed sample. Recen…
Taylor series perspective on ab initio path integral Monte Carlo simulations with Fermi-Dirac statistics
Tobias Dornheim, Alexander Benedix Robles, Paul Hamann +6
The fermion sign problem constitutes a fundamental computational bottleneck across a plethora of research fields in physics, quantum chemistry and related disciplines. Recently, it…
A Momentum-Resolved X-ray Thomson Scattering Benchmark of Electronic-Response Models in Warm Dense Aluminium
Dmitrii S. Bespalov, Ulf Zastrau, Zhandos A. Moldabekov +58
The robust diagnosis of conditions generated in warm dense matter (WDM) experiments remains a persistent challenge. Here we describe the measurement of shock-compressed aluminium a…
Reweighting scheme for the calculation of grand-canonical expectation values in quantum Monte Carlo simulations with a fermion sign problem
Paul Hamann, Jan Vorberger, Tobias Dornheim
Ab initio path integral Monte Carlo (PIMC) simulations constitute the gold standard for the estimation of a broad range of equilibrium properties of a host of interacting quantum m…