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1. Nonequilibrium dynamics of axionlike particles: The quantum master equation

   https://doi.org/10.1103/PhysRevD.107.063518  

   Cao, Shuyang; Boyanovsky, Daniel (March 2023, Physical Review D)

   We study the nonequilibrium dynamics of axionlike particles (ALP) coupled to Standard Model degrees of freedom in thermal equilibrium. The quantum master equation (QME) for the ALP reduced density matrix is derived to leading order in the coupling of the ALP to the thermal bath, but to all orders of the bath couplings to degrees of freedom within or beyond the Standard Model other than the ALP. The QME describes the damped oscillation dynamics of an initial misaligned ALP condensate, thermalization with the bath, decoherence, and entropy production within a unifying framework. The ALP energy density features two components: a “cold” component from the misaligned condensate and a “hot” component from thermalization with the bath. 

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2. Searching for dark matter with a spin-based interferometer

   https://doi.org/10.1038/s41467-025-60178-6  

   Gavilan-Martin, Daniel; Łukasiewicz, Grzegorz; Padniuk, Mikhail; Klinger, Emmanuel; Smolis, Magdalena; Figueroa, Nataniel L; Jackson_Kimball, Derek F; Sushkov, Alexander O; Pustelny, Szymon; Budker, Dmitry; et al (December 2025, Nature Communications)

   Axion-like particles (ALPs) arise from well-motivated extensions to the Standard Model and could account for dark matter. ALP dark matter would manifest as a field oscillating at an (as of yet) unknown frequency. The frequency depends linearly on the ALP mass and plausibly ranges from 10⁻²²to 10 eV/c². This motivates broadband search approaches. We report on a direct search for ALP dark matter with an interferometer composed of two atomic K-Rb-³He comagnetometers, one situated in Mainz, Germany, and the other in Kraków, Poland. We leverage the anticipated spatio-temporal coherence properties of the ALP field and probe all ALP-gradient-spin interactions covering a mass range of nine orders of magnitude. No significant evidence of an ALP signal is found. We thus place new upper limits on the ALP-neutron, ALP-proton and ALP-electron couplings reaching belowg_aNN < 10⁻⁹ GeV⁻¹,g_aPP < 10⁻⁷ GeV⁻¹andg_aee < 10⁻⁶ GeV⁻¹, respectively. These limits improve upon previous laboratory constraints for neutron and proton couplings by up to three orders of magnitude. 

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3. Predicting Licenses for Changed Source Code

   https://doi.org/10.1109/ASE.2019.00070  

   Liu, Xiaoyu; Huang, LiGuo; Ge, Jidong; Ng, Vincent (November 2019, Proceedings of the 34th IEEE/ACM International Conference on Automated Software Engineering)

   null (Ed.)

   Open source software licenses regulate the circumstances under which software can be redistributed, reused and modified. Ensuring license compatibility and preventing license restriction conflicts among source code during software changes are the key to protect their commercial use. However, selecting the appropriate licenses for software changes requires lots of experience and manual effort that involve examining, assimilating and comparing various licenses as well as understanding their relationships with software changes. Worse still, there is no state-of-the-art methodology to provide this capability. Motivated by this observation, we propose in this paper Automatic License Prediction (ALP), a novel learning-based method and tool for predicting licenses as software changes. An extensive evaluation of ALP on predicting licenses in 700 open source projects demonstrate its effectiveness: ALP can achieve not only a high overall prediction accuracy (92.5% in micro F1 score) but also high accuracies across all license types. 

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4. Frequency‐Scanning Considerations in Axionlike Dark Matter Spin‐Precession Experiments

   https://doi.org/10.1002/andp.202300223  

   Zhang, Yuzhe; Tumturk, Deniz Aybas; Bekker, Hendrik; Budker, Dmitry; Kimball, Derek F. Jackson; Sushkov, Alexander O.; Wickenbrock, Arne (November 2023, Annalen der Physik)

   Abstract Galactic dark matter may consist of axionlike particles (ALPs) that can be described as an “ultralight bosonic field” oscillating at the ALP Compton frequency. The ALP field can be searched for using nuclear magnetic resonance (NMR), where resonant precession of spins of a polarized sample can be sensitively detected. The ALP mass to which the experiment is sensitive is scanned by sweeping the bias magnetic field. The scanning either results in detection of ALP dark matter or rules out ALP dark matter with sufficiently strong couplings to nuclear spins over the range of ALP masses corresponding to the covered span of Larmor frequencies. In this work, scanning strategies are analyzed with the goal of optimizing the parameter‐space coverage via a proper choice of experimental parameters (e.g., the effective transverse relaxation time). 

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5. Predictions for axion couplings from ALP cogenesis

   https://doi.org/10.1007/JHEP01(2021)172  

   Co, Raymond T.; Hall, Lawrence J.; Harigaya, Keisuke (January 2021, Journal of High Energy Physics)

   null (Ed.)

   A bstract Adding an axion-like particle (ALP) to the Standard Model, with a field velocity in the early universe, simultaneously explains the observed baryon and dark matter densities. This requires one or more couplings between the ALP and photons, nucleons, and/or electrons that are predicted as functions of the ALP mass. These predictions arise because the ratio of dark matter to baryon densities is independent of the ALP field velocity, allowing a correlation between the ALP mass, m a , and decay constant, f a . The predicted couplings are orders of magnitude larger than those for the QCD axion and for dark matter from the conventional ALP misalignment mechanism. As a result, this scheme, ALP cogenesis, is within reach of future experimental ALP searches from the lab and stellar objects, and for dark matter. 

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