@online{chawlaMultipleLatentOrderings2026,title={Multiple latent orderings better predict language model preferences},author={Chawla, Aviral and Thompson, William H. W. and Young, Jean-Gabriel},date={2026},eprint={2609.22170},eprinttype={arXiv},}
Emergent contagion complexity: Disentangling mechanistic complexity from correlated heterogeneity
Katerina Tang, Daniel Kaiser, William Thompson, and
3 more authors
@online{tangEmergentContagionComplexity2026,title={Emergent contagion complexity: Disentangling mechanistic complexity from correlated heterogeneity},author={Tang, Katerina and Kaiser, Daniel and Thompson, William and Young, Jean-Gabriel and Hébert-Dufresne, Laurent and Landry, Nicholas W.},date={2026},eprint={2607.25139},eprinttype={arXiv},}
Simpson’s paradox explains the ubiquity of nonlinear, threshold, and complex contagions
Laurent Hébert-Dufresne, Antoine Allard, Jean-Gabriel Young, and
2 more authors
@online{hebertDufresneSimpsonsParadox2026,title={Simpson's paradox explains the ubiquity of nonlinear, threshold, and complex contagions},author={Hébert-Dufresne, Laurent and Allard, Antoine and Young, Jean-Gabriel and Thompson, William H. W. and St-Onge, Guillaume},date={2026},eprint={2605.00791},eprinttype={arXiv},}
Sensitivity analysis of epidemic forecasting and spreading on networks with probability generating functions
M. C. Boudreau, William H. W. Thompson, Chris M. Danforth, and
2 more authors
@article{boudreauSensitivityAnalysis2026,title={Sensitivity analysis of epidemic forecasting and spreading on networks with probability generating functions},author={Boudreau, M. C. and Thompson, William H. W. and Danforth, Chris M. and Young, Jean-Gabriel and Hébert-Dufresne, Laurent},date={2026},journaltitle={Journal of the Royal Society Interface},volume={23},number={235},pages={20250686},eprint={2506.24103},eprinttype={arXiv},doi={10.1098/rsif.2025.0686},url={https://doi.org/10.1098/rsif.2025.0686},}
2025
2024
Reconstructing Networks from Simple and Complex Contagions
Nicholas W. Landry, William Thompson, Laurent Hébert-Dufresne, and
1 more author
Network scientists often use complex dynamic processes to describe network contagions, but tools for fitting contagion models typically assume simple dynamics. Here, we address this gap by developing a nonparametric method to reconstruct a network and dynamics from a series of node states, using a model that breaks the dichotomy between simple pairwise and complex neighborhood-based contagions. We then show that a network is more easily reconstructed when observed through the lens of complex contagions if it is dense or the dynamic saturates, and that simple contagions are better otherwise.
@article{Landry2024b,title={Reconstructing Networks from Simple and Complex Contagions},author={Landry, Nicholas W. and Thompson, William and Hébert-Dufresne, Laurent and Young, Jean-Gabriel},date={2024-10-07},journaltitle={Physical Review E},shortjournal={Phys. Rev. E},volume={110},number={4},eprint={2405.00129},eprinttype={arXiv},eprintclass={cs},pages={L042301},issn={2470-0045, 2470-0053},doi={10.1103/PhysRevE.110.L042301},urldate={2025-05-21},langid={english},keywords={Computer Science - Social and Information Networks,notion,Quantitative Biology - Populations and Evolution,Statistics - Machine Learning},}
2023
Evolving Robust Facility Placements
Will Thompson, Alex Freidrichsen, Chris M Danforth, and
2 more authors
In Proceedings of the Companion Conference on Genetic and Evolutionary Computation
Robustness is a desired quality in many real-world engineered systems. The p-median problem is an optimization process in which a set of facilities must be found to minimize the average distance between each individual in a given population and the nearest facility. By introducing perturbations drawn from a specified distribution during evolution, we simulate the effect of natural disasters or other catastrophes on the placement of facilities. We use a non-dominated multi-objective procedure to select facilities with high fitness and robustness. We show that facilities evolved in this way are similarly fit and more robust than optimal solutions evolved without perturbation. Importantly, evolved facility layouts are much less susceptible to large catastrophic failures that are of the greatest concern in the placement of public infrastructure.
@inproceedings{Thompson2023,title={Evolving {{Robust Facility Placements}}},booktitle={Proceedings of the {{Companion Conference}} on {{Genetic}} and {{Evolutionary Computation}}},author={Thompson, Will and Freidrichsen, Alex and Danforth, Chris M and Dodds, Peter Sheridan and Cheney, Nicholas},date={2023-07-24},series={{{GECCO}} '23 {{Companion}}},pages={775--778},publisher={Association for Computing Machinery},location={New York, NY, USA},doi={10.1145/3583133.3590712},url={https://doi.org/10.1145/3583133.3590712},urldate={2023-09-11},isbn={979-8-4007-0120-7},keywords={complex systems,evolution of evolvability,evolutionary algorithms,genetic algorithms,location-allocation,notion,p-median problem,robustness,spatial distributions},}
Modeling Macaque Fighting Dynamics with the Evolutionary Model Discovery Framework to Understand Its Application and Utility
Alex Isherwood, Melanie Jutras, Matthew Koehler, and
3 more authors
@incollection{Isherwood2023,title={Modeling {{Macaque Fighting Dynamics}} with the {{Evolutionary Model Discovery Framework}} to {{Understand Its Application}} and {{Utility}}},booktitle={Proceedings of the 2022 {{Conference}} of {{The Computational Social Science Society}} of the {{Americas}}},author={Isherwood, Alex and Jutras, Melanie and Koehler, Matthew and Slater, David and Thompson, William and Yelenick, Maria},editor={Yang, Zining and Núñez-Corrales, Santiago},date={2023},pages={117--128},publisher={Springer International Publishing},location={Cham},doi={10.1007/978-3-031-37553-8_9},url={https://link.springer.com/10.1007/978-3-031-37553-8_9},urldate={2024-05-06},isbn={978-3-031-37552-1 978-3-031-37553-8},langid={english},keywords={notion},}
2022
The Structure and Dynamics of Modern United States Federal Case Law
Keerthi Adusumilli, Bradford Brown, Joey Harrison, and
9 more authors
The structure and dynamics of modern United States Federal Case Law are examined here. The analyses utilize large-scale network analysis tools, natural language processing techniques, and information theory to examine all the federal opinions in the Court Listener database, containing approximately 1.3 million judicial opinions and 11.4 million citations. The analyses are focused on modern United States Federal Case Law, as cases in the Court Listener database range from approximately 1926–2020 and include most Federal jurisdictions. We examine the data set from a structural perspective using the citation network, overall and by time and space (jurisdiction). In addition to citation structure, we examine the dataset from a topical and information theoretic perspective, again, overall and by time and space.
@article{adusumilliStructureDynamicsModern2022,title={The {{Structure}} and {{Dynamics}} of {{Modern United States Federal Case Law}}},author={Adusumilli, Keerthi and Brown, Bradford and Harrison, Joey and Koehler, Matthew and Kutarnia, Jason and Michel, Shaun and Olivier, Max and Pfeifer, Craig and Slater, Zoryanna and Thompson, William and Vetter, Dianna and Zacharowicz, Renee},date={2022},journaltitle={Frontiers in Physics},volume={9},issn={2296-424X},url={https://www.frontiersin.org/articles/10.3389/fphy.2021.695219},urldate={2022-12-24},}
2018
Levy Flights of the Collective Imagination
William H. W. Thompson, Zachary Wojtowicz, and Simon DeDeo
We present a structured random-walk model that captures key aspects of how people communicate in groups. Our model takes the form of a correlated L\’{e}vy flight that quantifies the balance between focused discussion of an idea and long-distance leaps in semantic space. We apply our model to three cases of increasing structural complexity: philosophical texts by Aristotle, Hume, and Kant; four days of parliamentary debate during the French Revolution; and branching comment trees on the discussion website Reddit. In the philosophical and parliamentary cases, the model parameters that describe this balance converge under coarse-graining to limit regions that demonstrate the emergence of large-scale structure, a result which is robust to translation between languages. Meanwhile, we find that the political forum we consider on Reddit exhibits a debate-like pattern, while communities dedicated to the discussion of science and news show much less temporal order, and may make use of the emergent, tree-like topology of comment replies to structure their epistemic explorations. Our model allows us to quantify the ways in which social technologies such as parliamentary procedures and online commenting systems shape the joint exploration of ideas.
@online{thompsonLevyFlightsCollective2018,title={Levy {{Flights}} of the {{Collective Imagination}}},author={Thompson, William H. W. and Wojtowicz, Zachary and DeDeo, Simon},date={2018-12-10},eprint={1812.04013},eprinttype={arXiv},eprintclass={nlin, physics:physics},doi={10.48550/arXiv.1812.04013},urldate={2022-12-24},pubstate={prepublished},keywords={Computer Science - Computation and Language,Computer Science - Social and Information Networks,Nonlinear Sciences - Adaptation and Self-Organizing Systems,Physics - Physics and Society},}
Coherent CAPTAIN-Mills collaboration
Papers from the CCM experiment at Los Alamos National Laboratory.
Axion-Like Particle Search with a Hybrid Cherenkov-Scintillation Detector
@online{aguilarArevaloAxionLikeSearch2026,title={Axion-Like Particle Search with a Hybrid Cherenkov-Scintillation Detector},author={Aguilar-Arevalo, A. A. and others},date={2026},eprint={2608.12616},eprinttype={arXiv},}
Testing Meson Portal Dark Sector Solutions to the MiniBooNE Anomaly at the Coherent CAPTAIN Mills Experiment
A. A. Aguilar-Arevalo, S. Biedron, J. Boissevain, and
42 more authors
A solution to the MiniBooNE excess invoking rare three-body decays of the charged pions and kaons to new states in the MeV mass scale was recently proposed as a dark-sector explanation. This class of solution illuminates the fact that, while the charged pions were focused in the target-mode run, their decay products were isotropically suppressed in the beam-dump-mode run in which no excess was observed. This suggests a new physics solution correlated to the mesonic sector. We investigate an extended set of phenomenological models that can explain the MiniBooNE excess as a dark sector solution, utilizing long-lived particles that might be produced in the three-body decays of the charged mesons and the two-body anomalous decays of the neutral mesons. Over a broad set of interactions with the long-lived particles, we show that these scenarios can be compatible with constraints from LSND, KARMEN, and MicroBooNE, and evaluate the sensitivity of the ongoing and future data taken by the Coherent CAPTAIN Mills experiment to a potential discovery in this parameter space. Published by the American Physical Society 2024
@article{Aguilar-Arevalo2024a,title={Testing Meson Portal Dark Sector Solutions to the {{MiniBooNE}} Anomaly at the {{Coherent CAPTAIN Mills}} Experiment},author={Aguilar-Arevalo, A. A. and Biedron, S. and Boissevain, J. and Borrego, M. and Bugel, L. and Chavez-Estrada, M. and Conrad, J. M. and Cooper, R. L. and Diaz, A. and Distel, J. R. and D’Olivo, J. C. and Dunton, E. and Dutta, B. and Fields, D. and Gochanour, J. R. and Gold, M. and Guardincerri, E. and Huang, E. C. and Kamp, N. and Kim, D. and Knickerbocker, K. and Louis, W. C. and Lyles, J. T. M. and Mahapatra, R. and Maludze, S. and Mirabal, J. and Newmark, D. and {deNiverville}, P. and Pandey, V. and Poulson, D. and Ray, H. and Renner, E. and Schaub, T. J. and Schneider, A. and Shaevitz, M. H. and Smith, D. and Sondheim, W. and Szelc, A. M. and Taylor, C. and Thompson, A. and Thompson, W. H. and Tripathi, M. and Thornton, R. T. and Van Berg, R. and Van De Water, R. G.},date={2024-05-13},journaltitle={Physical Review D},shortjournal={Phys. Rev. D},volume={109},number={9},pages={095017},issn={2470-0010, 2470-0029},doi={10.1103/PhysRevD.109.095017},url={https://link.aps.org/doi/10.1103/PhysRevD.109.095017},urldate={2025-05-21},langid={english},keywords={notion},}
First Dark Matter Search Results from Coherent CAPTAIN-Mills
This paper describes the operation of the Coherent CAPTAIN-Mills (CCM) detector located at the Los Alamos Neutron Science Center at Los Alamos National Laboratory. CCM is a 10-ton liquid argon detector located 20 meters from a high flux neutron/neutrino source and is designed to search for sterile neutrinos (νs’s) and light dark matter (LDM). An engineering run was performed in fall 2019 to study the characteristics of the CCM120 detector by searching for coherent scattering signals consistent with νs’s and LDM resulting from the production and decays of π+ and π0 in the tungsten target. New parameter space in a leptophobic dark matter (DM) model was excluded for DM masses between ∼2.0 and 30 MeV. The lessons learned from this run have guided the development and construction of the new CCM200 detector that will begin operations in 2021 and significantly improve on these searches.
@article{CCMCollaboration2022,title={First Dark Matter Search Results from {{Coherent CAPTAIN-Mills}}},author={},date={2022-07-05},journaltitle={Physical Review D},shortjournal={Phys. Rev. D},volume={106},number={1},pages={012001},publisher={American Physical Society},doi={10.1103/PhysRevD.106.012001},url={https://link.aps.org/doi/10.1103/PhysRevD.106.012001},urldate={2022-12-24},}
First Leptophobic Dark Matter Search from the Coherent–CAPTAIN-Mills Liquid Argon Detector
CCM Collaboration, A. A. Aguilar-Arevalo, D. S. M. Alves, and
49 more authors
We report the first results of a search for leptophobic dark matter (DM) from the Coherent–CAPTAIN-Mills (CCM) liquid argon (LAr) detector. An engineering run with 120 photomultiplier tubes (PMTs) and 17.9×1020 protons on target (POT) was performed in fall 2019 to study the characteristics of the CCM detector. The operation of this 10-ton detector was strictly light based with a threshold of 50 keV and used coherent elastic scattering off argon nuclei to detect DM. Despite only 1.5 months of accumulated luminosity, contaminated LAr, and nonoptimized shielding, CCM’s first engineering run has already achieved sensitivity to previously unexplored parameter space of light dark matter models with a baryonic vector portal. With an expected background of 115 005 events, we observe 115 005+16.5 events which is compatible with background expectations. For a benchmark mediator-to-DM mass ratio of mVB/mχ=2.1, DM masses within the range 9 MeV≲mχ≲50 MeV are excluded at 90% C. L. in the leptophobic model after applying the Feldman-Cousins test statistic. CCM’s upgraded run with 200 PMTs, filtered LAr, improved shielding, and 10 times more POT will be able to exclude the remaining thermal relic density parameter space of this model, as well as probe new parameter space of other leptophobic DM models.
@article{ccmcollaborationFirstLeptophobicDark2022,title={First {{Leptophobic Dark Matter Search}} from the {{Coherent--CAPTAIN-Mills Liquid Argon Detector}}},author={{CCM Collaboration} and Aguilar-Arevalo, A. A. and Alves, D. S. M. and Biedron, S. and Boissevain, J. and Borrego, M. and Chavez-Estrada, M. and Chavez, A. and Conrad, J. M. and Cooper, R. L. and Diaz, A. and Distel, J. R. and D’Olivo, J. C. and Dunton, E. and Dutta, B. and Elliott, A. and Evans, D. and Fields, D. and Greenwood, J. and Gold, M. and Gordon, J. and Guarincerri, E. and Huang, E. C. and Kamp, N. and Kelsey, C. and Knickerbocker, K. and Lake, R. and Louis, W. C. and Mahapatra, R. and Maludze, S. and Mirabal, J. and Moreno, R. and Neog, H. and {deNiverville}, P. and Pandey, V. and Plata-Salas, J. and Poulson, D. and Ray, H. and Renner, E. and Schaub, T. J. and Shaevitz, M. H. and Smith, D. and Sondheim, W. and Szelc, A. M. and Taylor, C. and Thompson, W. H. and Thornton, R. T. and Tripathi, M. and Van Berg, R. and Van de Water, R. G. and Verma, S. and Walker, K.},date={2022-07-05},journaltitle={Physical Review Letters},shortjournal={Phys. Rev. Lett.},volume={129},number={2},pages={021801},publisher={American Physical Society},doi={10.1103/PhysRevLett.129.021801},url={https://link.aps.org/doi/10.1103/PhysRevLett.129.021801},urldate={2022-12-24},}
Prospects for Detecting Axionlike Particles at the Coherent CAPTAIN-Mills Experiment
The CCM Collaboration, A. A. Aguilar-Arevalo, D. S. M. Alves, and
46 more authors
We show results from the Coherent CAPTAIN Mills (CCM) 2019 engineering run which begin to constrain regions of parameter space for axionlike particles (ALPs) produced in electromagnetic particle showers in an 800 MeV proton beam dump, and further investigate the sensitivity of ongoing data-taking campaigns for the CCM200 upgraded detector. Based on beam-on background estimates from the engineering run, we make realistic extrapolations for background reduction based on expected shielding improvements, reduced beam width, and analysis-based techniques for background rejection. We obtain reach projections for two classes of signatures; ALPs coupled primarily to photons can be produced in the tungsten target via the Primakoff process, and then produce a gamma-ray signal in the liquid argon CCM detector either via inverse Primakoff scattering or decay to a photon pair. ALPs with significant electron couplings have several additional production mechanisms (Compton scattering, e+e− annihilation, ALP-bremsstrahlung) and detection modes (inverse Compton scattering, external e+e− pair conversion, and decay to e+e−). In some regions, the constraint is marginally better than both astrophysical and terrestrial constraints. With the beginning of a three year run, CCM will be more sensitive to this parameter space by up to an order of magnitude for both ALP-photon and ALP-electron couplings. The CCM experiment will also have sensitivity to well-motivated parameter space of QCD axion models. It is only a recent realization that accelerator-based large volume liquid argon detectors designed for low-energy coherent neutrino and dark matter scattering searches are also ideal for probing ALPs in the unexplored ∼MeV mass scale.
First Event-by-Event Identification of Cherenkov Radiation from Sub-MeV Particles in Liquid Argon
@article{aguilarArevaloCherenkov2025,title={First Event-by-Event Identification of Cherenkov Radiation from Sub-MeV Particles in Liquid Argon},author={Aguilar-Arevalo, A. A. and others},date={2025},journaltitle={Physical Review Letters},volume={135},number={17},pages={171804},doi={10.1103/bklh-w3dn},url={https://doi.org/10.1103/bklh-w3dn},eprint={2507.08886},eprinttype={arXiv},}
Measurement of the Liquid Argon Scintillation Pulse Shape Using Differentiable Simulation in the Coherent CAPTAIN-Mills Experiment
@article{aguilarArevaloScintillation2025,title={Measurement of the Liquid Argon Scintillation Pulse Shape Using Differentiable Simulation in the Coherent CAPTAIN-Mills Experiment},author={Aguilar-Arevalo, A. A. and others},date={2025},journaltitle={Physical Review D},volume={112},number={7},pages={072010},doi={10.1103/34mf-z6l9},url={https://doi.org/10.1103/34mf-z6l9},eprint={2507.08887},eprinttype={arXiv},}
