{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"55e3c52dc208d94c55956d21efc74f34be2468b0d80ddad9826f0fd379fce248","created":"2026-10-03T07:18:01Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"fcb034db7baf4f39eaba3511a49ea37b6dac331face484d8037f863630ad3f0a","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"cm.weyl-semimetals.chiral-anomaly-magnetoresistance","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"Many semimetals conduct better when a magnetic field points along the current, as the chiral anomaly predicts, but uneven current flow inside the sample (current jetting) can produce the same effect.","posed_since":"2013","precise":"In Weyl and Dirac semimetals (Na3Bi, Cd3As2, the TaAs family, ZrTe5), the chiral anomaly predicts a longitudinal conductivity increase $\\Delta \\sigma_{zz} = C_a B^2$ for $E$ parallel to $B$, with $C_a$ proportional to $v^{3}\\tau_v/\\mu^{2}$ ($v$ Fermi velocity, $\\tau_v$ intervalley scattering time, $\\mu$ chemical potential from the node). Determine for each material whether the measured negative magnetoresistance follows this scaling once current jetting and inhomogeneity are excluded. An answer is a material-by-material verdict with $\\tau_v$ measured independently.","problem_ref":null,"references":"","settled_by":"Multi-contact potential mapping that excludes current jetting, with $C_a$ measured versus $\\mu$ across gated or doped samples and compared with independently measured $\\tau_v$.","status_note":"","title":"Is negative longitudinal magnetoresistance a chiral-anomaly signature","topic_ref":"2be8f71440ef80a2f6a5c39e87f067e4bb75be81175ba895e94387a2b67affde"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"e3b4723b110de842ca62e4b6464074e3a62a731d2edeb4469cca1e9fd49bc445","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"5daf283be10dddbe77b5be02c121ea7a3552f47edf08cf5b65e32339383141a4","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"HEcjLfIip3Zy155HfuVUgHNifzbn4h3AXHV23Bwi1EjMoG0vF2MgTp73cCTnH7Ee18EyWeaIwV1tEmWJiUp0Cg"},"schema":"pubphys.envelope/1"},"record_hash":"e3b4723b110de842ca62e4b6464074e3a62a731d2edeb4469cca1e9fd49bc445","leaf_index":1214}