{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"9c1636d6cd0a95d9cce6a3d56ed149ae2c6ecb2595cd275c321e89ce095d52f8","created":"2026-10-03T07:17:53Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"ac043784b658ffe443c47ed92171754aa72e50204d7eed4515e7cb67fce0a7d6","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"amo.constant-variation.quasar-alpha-dipole","kind":"phenomenon","literature_status":"contested","n":"1","parents":[],"plain":"Light from distant quasars passes through gas clouds that absorb at wavelengths set by $\\alpha$ at that place and time. Some analyses claimed $\\alpha$ differs slightly in opposite directions on the sky, while newer instruments see no change.","posed_since":"2011","precise":"Many-multiplet analyses of Keck and VLT spectra (Webb et al 2011) reported a dipole in $\\Delta \\alpha/\\alpha$ of order $1e-5$ across the sky at about $4\\sigma$; ESPRESSO measurements (Murphy et al 2022) found $\\Delta \\alpha/\\alpha = (1.3 \\pm 1.3\\,\\mathrm{stat} \\pm 0.4\\,\\mathrm{sys})\\,\\mathrm{ppm}$ toward HE0515-4414. Establish whether any spatial or redshift variation of $\\alpha$ exists at the $1\\,\\mathrm{ppm}$ level once wavelength-calibration, isotopic-abundance and blinding systematics are controlled.","problem_ref":null,"references":"","settled_by":"A blinded ESPRESSO, ANDES or ELT survey of many absorbers across the sky with sub-ppm per-system precision and laser-comb calibration.","status_note":"A 2024 reanalysis claimed a $7\\sigma$ difference between two absorbers toward HE0515-4414 if Mg isotopic abundances are terrestrial; this depends on the assumed isotope ratios and is disputed.","title":"Is there a spatial dipole in $\\alpha$ from quasar absorption spectra?","topic_ref":"0d5d25a5bcd4a09341050ed67516a89341dcb76395d21eb07382fa82d8edaaf2"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"1505e833e79f89b0470e69ae66964130d3b7976c65fa5488c5c3277221511966","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"871fc84ad34ed51704882e6b209e8004cd564a8c5a8f853190b862e30b48e744","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"i2JP9eJKZ3YItKkG6Ubvnvac3fwn2HVI9tobXvr8odc-CmZ7WIYeZFRkOjHwornD1_AVOimpHJRqFdgO9f6mCQ"},"schema":"pubphys.envelope/1"},"record_hash":"1505e833e79f89b0470e69ae66964130d3b7976c65fa5488c5c3277221511966","leaf_index":393}