{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"9958240c38754b470c62fbd8febc7933ce9786e7f3228e46a837b4c07dcae372","created":"2026-10-03T07:17:54Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"917981a07b65c893a362ebc73b8bad19a49ea6d2ff5a6bdeaef779be8c6aee28","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"amo.unitary-fermi-transport.qpc-excess-conductance","kind":"phenomenon","literature_status":"partially-resolved","n":"1","parents":[],"plain":"When two clouds of strongly interacting fermions are joined by a narrow channel, atoms flow through faster than the quantum limit for independent particles, even above the superfluid temperature. Pairing fluctuations are the leading explanation, but a full quantitative account is missing.","posed_since":"2015","precise":"Two reservoirs of Li-6 near unitarity connected by a quantum point contact with a few transverse modes, as in Krinner et al. (PNAS 2016). In the normal phase near $T_c$, the particle conductance $G$ exceeds the noninteracting value $1/h$ per mode while the spin conductance is suppressed. Determine whether transport by preformed pairs (pair fluctuations) accounts quantitatively for $G$ and the spin conductance $G_s$ as functions of $T/T_F$, interaction and gate potential, and at what $T$ quantization is restored. Answer: a theory reproducing $G$ and $G_s$ within experimental error.","problem_ref":null,"references":"","settled_by":"A calculation that reproduces measured $G$ and $G_s$ over temperature and interaction scans in one apparatus without fitted parameters.","status_note":"Pair-fluctuation transport was proposed to explain the enhancement (Liu, Zhai, Zhang, PRA 95, 013623, 2017); a parameter-free match across the full data set is not established.","title":"Origin of excess conductance of a strongly interacting gas through a constriction","topic_ref":"b4f1be3df3747cf1d62d5ccbaa2ed5e283f70c00fc559fc9419649add747e05b"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"ca4a92d65e61b67b2936070f78e5a66168cdf64c8fa3e1a2525cd38f4051e876","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"3cc3d1a41824ca731b8d55b72bed530893ad250448299a36f9b5397c33f49002","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"AobI0TnrK38YccOT2L90pSbsf_F7_2xqVKE-yVVQleB79MjJWazRAfk_poBuIYDVx1AEdcfLhWqzJmtkrZffDQ"},"schema":"pubphys.envelope/1"},"record_hash":"ca4a92d65e61b67b2936070f78e5a66168cdf64c8fa3e1a2525cd38f4051e876","leaf_index":475}