{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"42a24b4a6978d8ac6f14d2473d0f0074b582872d444e8897817139c09fd48a0b","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["81d541d2cfe752af1232938c6108a52bf0aceca17e04720ed2db69ce7bf50e40","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"78b78f929453acb9ca240198940abeed2c2b529e54c4f3c3e0de5c642574bad9","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":"2","parents":[],"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 $\\mathrm{MoS_2}$, 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":"81d541d2cfe752af1232938c6108a52bf0aceca17e04720ed2db69ce7bf50e40","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 $\\mathrm{MoS_2}$ (2017); uniqueness and model dependence of the inversion remain debated.","title":"Can harmonic spectra measure Berry curvature of a crystal?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"a37fe2b0ae9b5a92eb81e665c1388778e511f3b50452b57b85ae3e3b89781bc7","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"32157920e4eda159828e45d6ada4a6340eaf0610373a7e1541f20686ffd15f28","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"U_RHeYCWWSbSlLnKSHt-pQ9PnVep1Ul5fUKdAEmttrCnMIx4E-bPF2-yfyyiEsnrvlSjCaXUPj2nyyiI0nxxBA"},"schema":"pubphys.envelope/1"},"record_hash":"a37fe2b0ae9b5a92eb81e665c1388778e511f3b50452b57b85ae3e3b89781bc7","leaf_index":2190}