About

William Detmold is a Professor of Physics at MIT and a Graduate Program Faculty Coordinator. His research focuses on strong interaction dynamics in theoretical particle and nuclear physics. He employs analytic methods and supercomputers to solve complex equations of quantum chromodynamics (QCD) that describe the strong interaction, aiming to understand the emergence of hadrons and nuclei from the Standard Model of particle physics. His work seeks to determine the properties and interactions of these systems from first principles, confront experimental data, and make predictions for regimes such as the interior of neutron stars where experiments are not feasible. Professor Detmold obtained his PhD from the University of Adelaide, Australia, and joined the MIT physics faculty in 2012. Prior to MIT, he held appointments at the College of William and Mary and the University of Washington. He is a Fellow of the American Physical Society. His contributions include pioneering calculations of few-body hadronic systems using lattice quantum chromodynamics, including the spectrum of light nuclei and hypernuclei, Bose-condensed multimeson systems, and inelastic nuclear reactions.

Research topics

• Physics
• Particle physics
• Nuclear physics
• Computer Science
• Systems engineering
• Optics
• Engineering
• Engineering physics
• Astronomy

Selected publications

• Extracting the distribution amplitude of light pseudoscalar mesons using the HOPE method

  2025-02-21

  articleOpen access

  The pseudoscalar meson light-cone distribution amplitudes (LCDAs) are essential non-perturbative inputs for a range of high-energy exclusive processes in quantum chromodynamics. In this proceedings, progress towards a determination of the low Mellin moments of the pion and kaon LCDAs by the HOPE Collaboration is reported.

  PublisherOA PDFDOI

• Constraints on the finite volume two-nucleon spectrum at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>m</mml:mi><mml:mi>π</mml:mi></mml:msub><mml:mo>≈</mml:mo><mml:mn>806</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>MeV</mml:mi></mml:math>

  Physical review. D/Physical review. D. · 2025-06-02 · 7 citations

  articleOpen access1st authorCorresponding

  The low-energy, finite-volume spectrum of the two-nucleon system at a quark mass corresponding to a pion mass of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi>m</a:mi></a:mrow><a:mrow><a:mi>π</a:mi></a:mrow></a:msub><a:mo>≈</a:mo><a:mn>806</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>MeV</a:mi></a:mrow></a:math> is studied with lattice quantum chromodynamics (LQCD) using variational methods. The interpolating-operator sets used in [Variational study of two-nucleon systems with lattice QCD, .] are extended by including a complete basis of local hexaquark operators, as well as plane-wave dibaryon operators built from products of both positive- and negative-parity nucleon operators. Results are presented for the isosinglet and isotriplet two-nucleon channels. In both channels, noticeably weaker variational bounds on the lowest few energy eigenvalues are obtained from operator sets which contain only hexaquark operators or operators constructed from the product of two negative-parity nucleons, while other operator sets produce low-energy variational bounds which are consistent within statistical uncertainties. The consequences of these studies for the LQCD understanding of the two-nucleon spectrum are investigated.

  PublisherOA PDFDOI

• Matrix-free Neural Preconditioner for the Dirac Operator in Lattice Gauge Theory

  ArXiv.org · 2025-09-12

  preprintOpen access

  Linear systems arise in generating samples and in calculating observables in lattice quantum chromodynamics~(QCD). Solving the Hermitian positive definite systems, which are sparse but ill-conditioned, involves using iterative methods, such as Conjugate Gradient (CG), which are time-consuming and computationally expensive. Preconditioners can effectively accelerate this process, with the state-of-the-art being multigrid preconditioners. However, constructing useful preconditioners can be challenging, adding additional computational overhead, especially in large linear systems. We propose a framework, leveraging operator learning techniques, to construct linear maps as effective preconditioners. The method in this work does not rely on explicit matrices from either the original linear systems or the produced preconditioners, allowing efficient model training and application in the CG solver. In the context of the Schwinger model U(1) gauge theory in 1+1 spacetime dimensions with two degenerate-mass fermions), this preconditioning scheme effectively decreases the condition number of the linear systems and approximately halves the number of iterations required for convergence in relevant parameter ranges. We further demonstrate the framework learns a general mapping dependent on the lattice structure which leads to zero-shot learning ability for the Dirac operators constructed from gauge field configurations of different sizes.

  PublisherOA PDFDOI

• Aspects of Propagator Sparsening in Lattice QCD

  arXiv (Cornell University) · 2025-01-09

  preprintOpen accessSenior author

  In lattice field theory, field sparsening aims to replace quantum fields, or objects constructed from them, with approximations that preserve the appropriate symmetries and maintain many aspects of the physics that the fields determine. For example, an effective sparsening of a quark propagator provides an efficient map from a quark propagator on a fine lattice geometry to a quark propagator defined on a coarser geometry in order to reduce storage and computational costs of subsequent calculational stages while maintaining long-distance correlations and corresponding low-energy physical information. Previous studies have focused on decimating lattice sites or randomly sampling lattice sites to reduce the size of the propagator and subsequent costs of Wick contractions. Here, we extend the study of sparsening to incorporate covariant averaging of spatial sites and examine the effects on two-point and three-point correlation functions involving various hadrons. We find that sparsening is most effective in reproducing the unsparsened versions of these correlation functions when weighted covariant-averaging is sequentially applied many times.

  PublisherOA PDFDOI

• QCD Constraints on Isospin-Dense Matter and the Nuclear Equation of State

  Physical Review Letters · 2025-01-06 · 32 citations

  articleOpen access

  Understanding the behavior of dense hadronic matter is a central goal in nuclear physics as it governs the nature and dynamics of astrophysical objects such as supernovae and neutron stars. Because of the nonperturbative nature of quantum chromodynamics (QCD), little is known rigorously about hadronic matter in these extreme conditions. Here, lattice QCD calculations are used to compute thermodynamic quantities and the equation of state of QCD over a wide range of isospin chemical potentials with controlled systematic uncertainties. Agreement is seen with chiral perturbation theory when the chemical potential is small. Comparison to perturbative QCD at large chemical potential allows for an estimate of the gap in the superconducting phase, and this quantity is seen to agree with perturbative determinations. Since the partition function for an isospin chemical potential μ_{I} bounds the partition function for a baryon chemical potential μ_{B}=3μ_{I}/2, these calculations also provide rigorous nonperturbative QCD bounds on the symmetric nuclear matter equation of state over a wide range of baryon densities for the first time.

  PublisherDOI

• Correlation function distributions for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>O</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mi>N</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:math> lattice field theories in the disordered phase

  Physical review. D/Physical review. D. · 2024-02-16 · 1 citations

  articleOpen accessSenior author

  Numerical computations in strongly interacting quantum field theories are often performed using Monte Carlo sampling methods. A key task in these calculations is to estimate the value of a given physical quantity from the distribution of stochastic samples that are generated using the Monte Carlo method. Typically, the sample mean and sample variance are used to define the expectation values and uncertainties of computed quantities. However, the Monte Carlo sample distribution contains more information than these basic properties, and it is useful to investigate it more generally. In this work, the exact form of the probability distributions of two-point correlation functions at zero momentum in <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>O</a:mi><a:mo stretchy="false">(</a:mo><a:mi>N</a:mi><a:mo stretchy="false">)</a:mo></a:math> lattice field theories in the disordered phase and in infinite volume are determined. These distributions allow for a robust investigation of the efficacy of the Monte Carlo sampling procedure and are shown also to allow for improved estimators of the target physical quantity to be constructed. The theoretical expectations are shown to agree with numerical calculations in the <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>O</e:mi><e:mo stretchy="false">(</e:mo><e:mn>2</e:mn><e:mo stretchy="false">)</e:mo></e:math> model. Published by the American Physical Society 2024

  PublisherOA PDFDOI

• Exploring gauge-fixing conditions with gradient-based optimization

  arXiv (Cornell University) · 2024-10-04

  preprintOpen access1st authorCorresponding

  Lattice gauge fixing is required to compute gauge-variant quantities, for example those used in RI-MOM renormalization schemes or as objects of comparison for model calculations. Recently, gauge-variant quantities have also been found to be more amenable to signal-to-noise optimization using contour deformations. These applications motivate systematic parameterization and exploration of gauge-fixing schemes. This work introduces a differentiable parameterization of gauge fixing which is broad enough to cover Landau gauge, Coulomb gauge, and maximal tree gauges. The adjoint state method allows gradient-based optimization to select gauge-fixing schemes that minimize an arbitrary target loss function.

  PublisherOA PDFDOI

• Erratum: Variational study of two-nucleon systems with lattice QCD [Phys. Rev. D <b>107</b>, 094508 (2023)]

  Physical review. D/Physical review. D. · 2024-12-27 · 2 citations

  erratumOpen access
  PublisherDOI

• Constraints on the finite volume two-nucleon spectrum at $m_π\approx 806$ MeV

  arXiv (Cornell University) · 2024-04-18

  preprintOpen access1st authorCorresponding

  The low-energy finite-volume spectrum of the two-nucleon system at a quark mass corresponding to a pion mass of $m_π\approx 806$ MeV is studied with lattice quantum chromodynamics (LQCD) using variational methods. The interpolating-operator sets used in [Phys.Rev.D 107 (2023) 9, 094508] are extended by including a complete basis of local hexaquark operators, as well as plane-wave dibaryon operators built from products of both positive- and negative-parity nucleon operators. Results are presented for the isosinglet and isotriplet two-nucleon channels. In both channels, noticably weaker variational bounds on the lowest few energy eigenvalues are obtained from operator sets which contain only hexaquark operators or operators constructed from the product of two negative-parity nucleons, while other operator sets produce low-energy variational bounds which are consistent within statistical uncertainties. The consequences of these studies for the LQCD understanding of the two-nucleon spectrum are investigated.

  PublisherOA PDFDOI

• LDIC Survey 2023: Feeling Welcome in the Community

  2024-05-03

  articleOpen access

  We review the level of welcomeness that members of the lattice field theory community feel based on the results of a survey performed in May and June 2023. While respondents reported generally high levels of feeling welcome at the lattice conference, women and people with diverse gender identities, sexual orientations, ethnic backgrounds and religious affiliations feel less included and have more negative experiences at the lattice conference than their peers. Respondents report that they are actively informing themselves about inequities in the community, however a large fraction of survey participants underestimate the severity of the problem, as was found in previous surveys. The survey data indicate that this situation can be most effectively improved by organizing talks and events about issues of diversity and inclusion within the lattice community. Respondents also reported that individual readings of scientific papers on equity and inclusion are effective in giving people agency in making a change and hence it may be helpful to collate a collection of important articles on these topics.

  PublisherOA PDFDOI

Frequent coauthors

• Kostas Orginos

  William & Mary

  353 shared

• Phiala E. Shanahan

  The NSF AI Institute for Artificial Intelligence and Fundamental Interactions

  237 shared

• Brian C. Tiburzi

  City College of New York

  219 shared

• Martin J. Savage

  205 shared

• Silas R. Beane

  184 shared

• Michael L. Wagman

  Fermi National Accelerator Laboratory

  180 shared

• Wally Melnitchouk

  Thomas Jefferson National Accelerator Facility

  163 shared

• Emmanuel Chang

  The NSF AI Institute for Artificial Intelligence and Fundamental Interactions

  159 shared

Awards & honors

• Fellow, American Physical Society (2016)
• Early Career Research Program Award, Department of Energy (2…
• Outstanding Junior Investigator Award, Department of Energy…