About

Berndt Mueller is the J. B. Duke Professor of Physics at Duke University, specializing in theoretical nuclear and particle physics. His research primarily focuses on (nuclear) matter at extreme energy density, particularly the properties of quark-gluon plasma, which is predicted by quantum chromodynamics (QCD) to form when nuclear matter exceeds a critical energy density. Mueller and his collaborators study the formation of this plasma, with an emphasis on the process of thermalization, and develop methods for its detection in high-energy nuclear collisions. His work explores the behavior of hot and dense nuclear matter, including relativistic heavy-ion physics, the QCD phase boundary, and issues related to the search for the critical point in QCD. Mueller has contributed to the understanding of the quark-gluon plasma through various publications and whitepapers, and actively engages in research related to the exploration of the fundamental forces that govern nuclear matter under extreme conditions.

Research topics

• Physics
• Nuclear physics
• Political Science
• Computer Science
• Machine Learning
• Particle physics
• Quantum mechanics
• Chemistry
• Engineering
• Geography
• Aerospace engineering

Selected publications

• Quark flavor equilibration of the quark-gluon plasma

  arXiv (Cornell University) · 2025-01-11

  preprintOpen access

  The early stage of a heavy-ion collision is marked by rapid entropy production and the transition from a gluon saturated initial condition to a plasma of quarks and gluons that evolves hydrodynamically. However, during the early times of the hydrodynamic evolution, the chemical composition of the QCD medium is still largely unknown. We present a study of quark chemical equilibration in the (Q)GP using a novel model of viscous hydrodynamic evolution in partial chemical equilibrium. Motivated by the success of gluon saturated initial condition models, we initialize the QCD medium as a completely gluon dominated state. Local quark production during the hydrodynamic phase is then simulated through the evolution of time-dependent fugacities for each independent quark flavor, with the timescales set as free parameters to compare different rates of equilibration. We present the results of complete heavy-ion collision simulations using this partial chemical equilibrium model, and show the effects on hadronic and electromagnetic observables. In particular, we show that the development of flow is sensitive to the equilibration timescale, providing an empirical way to probe the chemical equilibration of the QCD medium.

  PublisherOA PDFDOI

• Holography for BCFTs with Multiple Boundaries: Multi-Splitting Quenches

  University of Regensburg Publication Server (University of Regensburg) · 2024-12-02

  preprintOpen access

  We elaborate on the method introduced in arXiv:2403.02165 for holographic duals of Boundary Conformal Field Theories (BCFTs) with multiple boundaries. Naïvely, as the number of boundaries grow large such a calculation becomes unmanageable. We show that is not always the case. Using these advances we calculate the entanglement entropy as a function of time for 1+1-dimensional CFTs that are split into N subsystems. We give explicit results for N = 4 and N = 17. We find that all qualitative differences that arise for larger N are present N = 4.

  PublisherOA PDFDOI

• Quantum Information Science and Technology for Nuclear Physics. Input into U.S. Long-Range Planning, 2023

  arXiv (Cornell University) · 2023 · 5 citations

  • Political Science
  • Physics
  • Political Science

  In preparation for the 2023 NSAC Long Range Plan (LRP), members of the Nuclear Science community gathered to discuss the current state of, and plans for further leveraging opportunities in, QIST in NP research at the Quantum Information Science for U.S. Nuclear Physics Long Range Planning workshop, held in Santa Fe, New Mexico on January 31 - February 1, 2023. The workshop included 45 in-person participants and 53 remote attendees. The outcome of the workshop identified strategic plans and requirements for the next 5-10 years to advance quantum sensing and quantum simulations within NP, and to develop a diverse quantum-ready workforce. The plans include resolutions endorsed by the participants to address the compelling scientific opportunities at the intersections of NP and QIST. These endorsements are aligned with similar affirmations by the LRP Computational Nuclear Physics and AI/ML Workshop, the Nuclear Structure, Reactions, and Astrophysics LRP Town Hall, and the Fundamental Symmetries, Neutrons, and Neutrinos LRP Town Hall communities.

  PublisherOA PDFDOI

• Measurement of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>R</mml:mi><mml:mo>=</mml:mo><mml:msub><mml:mi>σ</mml:mi><mml:mi>L</mml:mi></mml:msub><mml:mo>/</mml:mo><mml:msub><mml:mi>σ</mml:mi><mml:mi>T</mml:mi></mml:msub></mml:mrow></mml:math> and the separated longitudinal and transverse structure functions in the nucleon-resonance region

  Physical review. C · 2022 · 12 citations

  • Machine Learning
  • Physics
  • Particle physics

  We report on a detailed study of longitudinal strength in the nucleon resonance region, presenting new results from inclusive electron-proton cross sections measured at Jefferson Lab Hall C in the four-momentum transfer range $0.2&lt;{Q}^{2}&lt;5.5\phantom{\rule{4pt}{0ex}}{\mathrm{GeV}}^{2}$. The data have been used to accurately perform 167 Rosenbluth-type longitudinal/transverse separations. The precision $R={\ensuremath{\sigma}}_{L}/{\ensuremath{\sigma}}_{T}$ data are presented here, along with the first separate values of the inelastic structure functions ${F}_{1}$ and ${F}_{L}$ in this regime. The resonance longitudinal component is found to be significant, both in magnitude and in the existence of defined mass peaks. Additionally, quark-hadron duality is here observed above ${Q}^{2}=1\phantom{\rule{4pt}{0ex}}{\mathrm{GeV}}^{2}$ in the separated structure functions independently.

  PublisherOA PDFDOI

• Dynamic magnetic response of the quark-gluon plasma to electromagnetic fields

  Physical review. D/Physical review. D. · 2022-07-18 · 1 citations

  preprintOpen accessSenior author

  We investigate the electromagnetic response of a viscous quark-gluon plasma in the framework of the relativistic Boltzmann equation with current conserving collision term. Our formalism incorporates dissipative effects at all orders in linear response to the electromagnetic field while accounting for the full space and time dependence of the perturbing fields. As an example, we consider the collision of two nuclei in a stationary, homogeneous quark-gluon plasma. We show that for large collision energies the induced magnetic fields are governed by the response of quark-gluon plasma along the light cone. In this limit, we derive an analytic expression for the magnetic field along the beam axis between the receding nuclei and show that its strength varies only weakly with collision energy for $\sqrt{{s}_{\mathrm{NN}}}\ensuremath{\ge}30\text{ }\text{ }\mathrm{GeV}$.

  PublisherOA PDFDOI

• Herman Feshbach Prize in Theoretical Nuclear Physics (2021): Diagnosing the Quark-Gluon Plasma

  Bulletin of the American Physical Society · 2021-04-19

  article1st authorCorresponding
  Publisher

• Coupled Transport Equations for Quarkonium Production in Heavy Ion Collisions

  Proceedings of 10th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions — PoS(HardProbes2020) · 2021 · 3 citations

  Senior authorCorresponding
  • Physics
  • Particle physics
  • Nuclear physics

  Motivated by recent applications of the open quantum system formalism to understand quarkonium transport in the quark-gluon plasma, we develop a set of coupled Boltzmann equations for open heavy quark-antiquark pairs and quarkonia. Our approach keeps track of the correlation between the heavy quark-antiquark pair from quarkonium dissociation and thus is able to account for both uncorrelated and correlated recombination. By solving the coupled Boltzmann equations for current heavy ion collision experiments, we find correlated recombination is crucial to describe the data of bottomonia nuclear modification factors. To further test the importance of correlated recombination in experiments, we propose a new observable: $\frac{R_{AA}[\chi_b(1P)]}{R_{AA}[\Upsilon(2S)]}$. Future measurements of this ratio will help distinguish calculations with and without correlated recombination.

  PublisherOA PDFDOI

• Baked Alaska: the Fate of Heavy Quark Bound States inside Quark-gluon Plasma

  APS April Meeting Abstracts · 2019-01-01

  article
  Publisher

• IUPAP Report 41 Introduction

  Zenodo (CERN European Organization for Nuclear Research) · 2018-05-17 · 1 citations

  preprintOpen access

  IUPAP Report 41 is a document that gives summary information about the major nuclear physics facilities around the world. It is updated approximately every five years by Working Group 9 of the International Union of Pure and Applied Physics. The introduction to the report gives an overview of the field of nuclear physics and outlines the major questions facing the field. This most recent version of Report 41 has been updated to reflect the state of the field in 2018. The full report can be found at http://www.triumf.info/hosted/iupap/icnp/report41.html

  PublisherDOI

• Proposal for a Topical Collaboration on Quantitative Jet and Electromagnetic Tomography (JET) of Extreme Phases of Matter in Heavy-ion Collisions

  2015-01-01

  article
  Publisher

Frequent coauthors

• P. E. Reimer

  Argonne National Laboratory

  44 shared

• V. Papavassiliou

  42 shared

• C. Keppel

  38 shared

• N. C. R. Makins

  University of Aveiro

  38 shared

• A. Lung

  38 shared

• J. Arrington

  38 shared

• D. F. Geesaman

  Argonne National Laboratory

  36 shared

• E. Hawker

  33 shared

Labs

• Berndt Mueller LabPI

Awards & honors

• 2021 Herman Feshbach Prize in Theoretical Nuclear Physics