Joshua Foster, Pappalardo Fellow

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Area of Physics

Theoretical Nuclear and Particle Physics; Theoretical Astrophysics; Experimental Nuclear and Particle Physics

Research Interests

Joshua Foster works at the interface of theoretical particle physics, observational astronomy, and precision measurement.

His research is focused on the identification of dark matter and dark sectors by determining how signals of new physics may manifest in astrophysical systems and the laboratory. A theorist by training, he is particularly interested in searches for new physics in real data and the application of high-performance computing to phenomenology.

Joshua’s PhD work and ongoing research have focused on several aspects of axion phenomenology, including production and small-scale structure formation, searches for axion-to-photon conversion in stellar environments using X-ray and radio telescopes, and searches for axions in laboratory experiments as a member of the ABRACADABRA experiment.

Joshua is also interested in a number of other motivated dark matter candidates, such as WIMPs, sterile neutrinos, and primordial black holes.

Biographical Sketch

Joshua was raised in Indianapolis, Indiana, and received his BS in physics and mathematics from Indiana University.

In 2021, he completed his PhD in particle phenomenology at the University of Michigan, Ann Arbor, working with Professor Benjamin Safdi, a 2014-2017 Pappalardo Fellow. In his free time, Joshua enjoys hiking, cooking, and coffee.

Selected Publications

• Foster, Joshua W. and Witte, Samuel J. and Lawson, Matthew and Linden, Tim and Gajjar, Vishal and Weniger, Christoph and Safdi, Benjamin R., “Extraterrestrial Axion Search with the Breakthrough Listen Galactic Center Survey,” Phys. Rev. Lett. 129 (2022), no 25, 251102, arXiv:2202.08274 [astro-ph.CO].
• Christopher Dessert, Joshua W. Foster, Benjamin R. Safdi, “X-ray Searches for Axions from Super Star Clusters,” Phys. Rev. Lett. 125 (2020) no. 26, 261102, arXiv: 2008:03305 [hep-ph].
• Joshua W. Foster et al., “Green Bank and Effelsberg Radio Telescope Searches for Axion Dark Matter Conversion in Neutron Star Magnetospheres,” Phys. Rev. Lett. 125 (2020) no. 17, 171301, arXiv: 2004.00011 [astro-ph.CO].
• Malte Buschmann, Joshua W. Foster, Benjamin R. Safdi, “Early-Universe Simulations of the Cosmological Axion,” Phys. Rev. Lett. 124 (2020) no. 16, 161103, arXiv:1906.00967 [astro-ph.CO].
• Jonathan L. Ouellet, Chiara P. Salemi, Joshua Foster, et al. “First Results from ABRACADABRA-10 cm: A Search for Sub-µeV Axion Dark Matter, ” Phys. Rev. Lett. 122 (2019) no. 12, 121802, arXiv: 1810.12257 [hep-ex].
• Joshua W. Foster, Nicholas L. Rodd, Benjamin R. Safdi, “Revealing the Dark Matter Halo with Axion Direct Detection,” Phys. Rev. D. 97 (2018) no. 12, 123006, arXiv: 1711.10489 [astro-ph.CO].