{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"9b164cc6741931b5ff5b82cdc24bddb45769aae2bdbabff04a3e7838d598a06a","created":"2026-10-03T07:17:53Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["183e79026db85b21406f5df4c36a6c7d3635be9ca1f4246146875d83810df5d8","5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"20984ccbb705b7ce0a232f78316a6fb3914354214ebea71a8e9aa5c2b6f0e229","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"amo.attosecond-electron-dynamics.hhg-berry-curvature","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[{"note":"","parent_revision":"183e79026db85b21406f5df4c36a6c7d3635be9ca1f4246146875d83810df5d8","relation":"special_case"}],"plain":"In crystals lacking mirror symmetry, electrons pushed by a field also drift sideways because of a geometric property of their bands called Berry curvature. Harmonics polarized at right angles to the laser might read this property out, if other effects can be excluded.","posed_since":"2017","precise":"In noncentrosymmetric materials (monolayer MoS2, hBN, $\\alpha$-quartz) the anomalous velocity $v = -(e/\\hbar)\\ E\\ x\\ \\Omega(k)$, with $\\Omega(k)$ the Berry curvature, generates even-order harmonics polarized perpendicular to the drive. Question: can the perpendicular even-harmonic amplitudes and phases be inverted to give $\\Omega(k)$ along the driven trajectories with a stated accuracy, given interband contributions and propagation. An answer is a retrieval in a material with independently known Omega(k) that agrees within the stated uncertainty, or a proof that the inversion is not unique.","problem_ref":null,"references":"","settled_by":"A blind retrieval of $\\Omega(k)$ from harmonic data in a material whose Berry curvature is fixed by ab initio band theory and by an independent transport or optical measurement.","status_note":"Retrievals were reported in $\\alpha$-quartz (Luu and Woerner, Nature Communications 2018) and even harmonics attributed to Berry curvature in MoS2 (2017); uniqueness and model dependence of the inversion remain debated.","title":"Can harmonic spectra measure Berry curvature of a crystal?","topic_ref":"0df42c165abe2c701f655081b1ae2c457e3434bf87099b8b980410a52274fe98"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"81d541d2cfe752af1232938c6108a52bf0aceca17e04720ed2db69ce7bf50e40","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"8fcdfea40e30ba1fd84cc3fd5a0f3f333f38ead6c53daa2da2bd2ab68658e673","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"dM1b287aLcO2Tg_zMbkEiMOaJS2vclxF8YGJFssj9QNiJ4DLSeUsArt4b0fq62Dz8PKFhIa55fIMjSrcWZtlDQ"},"schema":"pubphys.envelope/1"},"record_hash":"81d541d2cfe752af1232938c6108a52bf0aceca17e04720ed2db69ce7bf50e40","leaf_index":370}