• Bayesian inference of real-time dynamics from lattice QCD 

      Rothkopf, Alexander Karl (Peer reviewed; Journal article, 2022)
      The computation of dynamical properties of nuclear matter, ranging from parton distribution functions of nucleons and nuclei to transport properties in the quark-gluon plasma, constitutes a central goal of modern theoretical ...
    • Bottomonium suppression at RHIC and LHC 

      Krouppa, Brandon; Rothkopf, Alexander Karl; Strickland, Michael (Peer reviewed; Journal article, 2019-02)
      The strong suppression of heavy quarkonia is a good indicator that one has generated a quark-gluon plasma (QGP) in an ultrarelativistic heavy ion collision. Recent advancements in first principles calculations of the heavy ...
    • Bryan’s Maximum Entropy Method—Diagnosis of a Flawed Argument and Its Remedy 

      Rothkopf, Alexander Karl (Peer reviewed; Journal article, 2020-09)
      The Maximum Entropy Method (MEM) is a popular data analysis technique based on Bayesian inference, which has found various applications in the research literature. While the MEM itself is well-grounded in statistics, I ...
    • The complex heavy-quark potential in an anisotropic quark-gluon plasma — Statics and dynamics 

      Dong, Lihua; Guo, Yun; Islam, Ajaharul; Rothkopf, Alexander Karl; Strickland, Michael (Peer reviewed; Journal article, 2022)
      We generalize a complex heavy-quark potential model from an isotropic QCD plasma to an anisotropic one by replacing the Debye mass mD with an anisotropic screening mass depending on the quark pair alignment with respect ...
    • Heavy quarkonium in extreme conditions 

      Rothkopf, Alexander Karl (Peer reviewed; Journal article, 2020)
      In this report we review recent progress achieved in the understanding of heavy quarkonium under extreme conditions from a theory perspective. Its focus lies both on quarkonium properties in thermal equilibrium, as well ...
    • Improved Gauss law model and in-medium heavy quarkonium at finite density and velocity 

      Lafferty, David; Rothkopf, Alexander Karl (Peer reviewed; Journal article, 2020-03)
      We explore the in-medium properties of heavy-quarkonium states at finite baryochemical potential and finite transverse momentum based on a modern complex-valued potential model. Our starting point is a novel, rigorous ...
    • Lattice study of static quark-antiquark interactions in dense quark matter 

      Astrakhantsev, Nikita Yu.; Bornyakov, Vitaly G.; Braguta, Victor V.; Ilgenfritz, Ernst-Michael; Kotov, Andrey Yuryevich; Nikolaev, Alexander A.; Rothkopf, Alexander Karl (Peer reviewed; Journal article, 2019-05)
      In this paper we study the interactions among a static quark-antiquark pair in the presence of dense two-color quark matter with lattice simulation. To this end we compute Polyakov line correlation functions and determine ...
    • A new variational discretization technique for initial value problems bypassing governing equations 

      Rothkopf, Alexander Karl; Nordström, Jan (Peer reviewed; Journal article, 2023-03)
      Motivated by the fact that both the classical and quantum description of nature rest on causality and a variational principle, we develop a novel and highly versatile discretization prescription for classical initial value ...
    • Proper static potential in classical lattice gauge theory at finite T 

      Lehmann, Alexander; Rothkopf, Alexander Karl (Peer reviewed; Journal article, 2021)
      We compute the proper real-time interaction potential between a static quark and antiquark in classical lattice gauge theory at finite temperature. Our central result is the determination of the screened real-part of this ...
    • Quantum dynamical dissociation of quarkonia by wave function decoherence in quark-gluon plasma 

      Kajimoto, Shiori; Akamatsu, Yukinao; Asakawa, Masayuki; Rothkopf, Alexander Karl (Peer reviewed; Journal article, 2019-02)
      In this study, we investigate the real-time evolution of quarkonium bound states in a quark-gluon plasma in an improved QCD based stochastic potential model. This model describes the quarkonium dynamics in terms of a ...
    • Quarkonium phenomenology from a generalised Gauss law 

      Lafferty, David; Rothkopf, Alexander Karl (Peer reviewed; Journal article, 2019-05)
      We present an improved analytic parametrisation of the complex in-medium heavy quark potential derived rigorously from the generalised Gauss law. To this end we combine in a self-consistent manner a non-perturbative vacuum ...
    • Quarkonium production and suppression: Theory 

      Rothkopf, Alexander Karl (Peer reviewed; Journal article, 2021-01)
      Heavy quarkonium theory has seen significant progress over the past years. Not only has the community steadily improved the understanding of fully equilibrated quarkonium using first principles lattice QCD studies, but it ...
    • Quarkonium production in the QGP 

      Rothkopf, Alexander Karl (Peer reviewed; Journal article, 2019-05)
      We report on recent theory progress in understanding the production of heavy quarkonium in heavy-ion collisions based on the in-medium heavy-quark potential extracted from lattice QCD simulations. On the one hand, the ...
    • Real time simulation of quarkonium in a thermal medium using a 3D Lindblad equation 

      Matre, Aslak (Master thesis, 2022)
      Using a new finite difference operator RN-SBP that has recently been developed and used for 1D simulations of the Lindblad equation, we extend it to the 3D case. We have not quite been able to implement the RN-SBP properly ...
    • Realistic in-medium heavy-quark potential from high statistics lattice QCD simulations 

      Petreczky, Peter; Rothkopf, Alexander Karl; Weber, Johannes Heinrich (Peer reviewed; Journal article, 2019)
      We present our first results on a direct computation of the complex in-medium heavy quark potential from realistic lattice QCD simulations. Ensembles with Nτ = 12 from the HotQCD and TUMQCD collaboration offer unprecedented ...
    • Reconstructing parton distribution functions from Ioffe time data: from Bayesian methods to Neural Networks 

      Karpie, Joseph; Orginos, Kostas; Rothkopf, Alexander Karl; Zafeiropoulos, Savvas (Peer reviewed; Journal article, 2019)
      The computation of the parton distribution functions (PDF) or distribution amplitudes (DA) of hadrons from first principles lattice QCD constitutes a central open problem. In this study, we present and evaluate the efficiency ...
    • Stable solvers for real-time Complex Langevin 

      Alvestad, Daniel; Larsen, Rasmus Normann; Rothkopf, Alexander Karl (Peer reviewed; Journal article, 2021-08)
      This study explores the potential of modern implicit solvers for stochastic partial differential equations in the simulation of real-time complex Langevin dynamics. Not only do these methods offer asymptotic stability, ...
    • Static quark-antiquark interactions at nonzero temperature from lattice QCD 

      Bala, Dibyendu; Kaczmarek, Olaf; Larsen, Rasmus Normann; Mukherjee, Swagato; Parkar, Gaurang Yatin; Petreczky, Peter; Rothkopf, Alexander Karl; Weber, Johannes Heinrich (Peer reviewed; Journal article, 2022)
      flavor lattice QCD calculations. The study consists of two parts. The first investigates the properties of Wilson line correlators in Coulomb gauge and compares to predictions of hard-thermal loop perturbation theory. As ...
    • Thermalization and dynamical spectral properties in the quark-meson model 

      Shen, Lisa; Berges, Jürgen; Pawlowski, Jan M.; Rothkopf, Alexander Karl (Peer reviewed; Journal article, 2020-07)
      We investigate the nonequilibrium evolution of the quark-meson model using two-particle irreducible effective action techniques. Our numerical simulations, which include the full dynamics of the order parameter of chiral ...
    • Towards learning optimized kernels for complex Langevin 

      Alvestad, Daniel; Larsen, Rasmus Normann; Rothkopf, Alexander Karl (Peer reviewed; Journal article, 2023)
      We present a novel strategy aimed at restoring correct convergence in complex Langevin simulations. The central idea is to incorporate system-specific prior knowledge into the simulations, in order to circumvent the NP-hard ...