{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"d53fa817a2399480328d18614bcaeccc6f59cd3c7b385add2e00e02f859a295b","created":"2026-10-03T07:18:05Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"47af5e4710cc589d32166eb85a538968d45adad65e8a64d0cad5ba0f5de2ac36","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"hep.sub-gev-detection.magnon-spin-coupling","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"In a magnet, spins can ripple together as a wave whose smallest unit is a magnon; dark matter that couples to electron spins could create one. Single magnons have been detected with a quantum bit, but no detector yet has the size and low noise needed for a dark matter search.","posed_since":"","precise":"Dark matter of mass $m_{\\chi} \\sim 1\\,\\mathrm{keV} - 1\\,\\mathrm{MeV}$ coupling to electron spin (e.g., via an axial-vector or magnetic-dipole interaction) excites gapped magnons of energy 1-100 meV in ordered magnets such as YIG, with rates computed by Trickle, Zhang and Zurek (Phys. Rev. Lett. 124, 201801, 2020). Single-magnon detection by a superconducting qubit was demonstrated with quantum efficiency up to 0.71 in a mm-scale ferrimagnetic crystal (Lachance-Quirion et al. 2020). The question is whether magnon counting can be scaled to target mass of about 1 kg with dark-count rate low enough to cross existing astrophysical bounds on spin-dependent couplings.","problem_ref":null,"references":"","settled_by":"A gram-scale or larger magnon detector with measured single-magnon dark-count rate, followed by a published dark matter limit.","status_note":"","title":"Can single-magnon counting probe spin-coupled sub-MeV dark matter?","topic_ref":"e60bc33f70ea44a1215dcfbe7831dd7817b64c21ad3c95ac918a82ec04971901"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"5c692084b969083881b269fac67e88e8c42f5dfe7873f125fa9c057908f565af","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"cb0e6f0cdfa1f6d3867095887d824d7f2463a17b014f932c5726bdbc07a28e7e","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"qQrfGSTD5lwp4Blt_MH9h9Bzv_gPCKsBrjAhM2B6mr_PighpM-ZcDDgPO-ggBzsPdRN5EfHyvIS3uYgRG2u3AQ"},"schema":"pubphys.envelope/1"},"record_hash":"5c692084b969083881b269fac67e88e8c42f5dfe7873f125fa9c057908f565af","leaf_index":1588}