doi:10.1103/PhysRevD.107.083510engEggemeier, B.O’Hare, C. A. J.Pierobon, G.Redondo, J.Wong, Y. Y. Y.Axion minivoids and implications for direct detectionART-2023-133522In the scenario in which QCD axion dark matter is produced after inflation, the Universe is populated by large inhomogeneities on very small scales. Eventually, these fluctuations will collapse gravitationally to form dense axion miniclusters that trap up to ∼75% of the dark matter within asteroid-mass clumps. Axion miniclusters are physically tiny however, so haloscope experiments searching for axions directly on Earth are much more likely to be probing “minivoids”—the space in between miniclusters. This scenario seems like it ought to spell doom for haloscopes, but while these minivoids might be underdense, they are not totally devoid of axions. Using Schrödinger-Poisson and N-body simulations to evolve from realistic initial field configurations, we quantify the extent to which the local ambient dark matter density is suppressed in the postinflationary scenario. We find that a typical experimental measurement will sample an axion density that is only around 10% of the expected galactic dark matter density. Our results are taken as conservative estimates and have implications for experimental campaigns lasting longer than a few years, as well as broadband haloscopes that have sensitivity to transient signatures. We show that for a Oð(year)-long integration times, the measured dark matter density should be expected to vary by 20%–30%.2023http://zaguan.unizar.es/record/12597310.1103/PhysRevD.107.083510http://zaguan.unizar.es/record/125973oai:zaguan.unizar.es:125973info:eu-repo/grantAgreement/ES/AEI-FEDER/PGC2018-095328-B-I00info:eu-repo/grantAgreement/ES/DGA/E12-7Rinfo:eu-repo/grantAgreement/EC/H2020/674896/EU/The Elusives Enterprise: Asymmetries of the Invisible Universe/ELUSIVESThis project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 674896-ELUSIVESPhysical Review D 107, 8 (2023), 083510 [18 pp.]byhttp://creativecommons.org/licenses/by/3.0/es/info:eu-repo/semantics/openAccess