{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"f04a32c3049008ac05e8c472a9cefac8b5be2156dbde87de48e2882d89c803f3","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":["ai:gpt-5.5"],"kind":"seed"},"parents":["a8b4857e61dbcfc526a2ad7e3847124ac6c5ba7d69b007e1ee9847bf1c439ac2","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"cc7b3b6ab3d5bb3caa99edb2ad708e2a2d08932efb9355e204e7e27012bb58e3","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":["ai:gpt-5.5"],"external_id":"cm.floquet-dtc.prethermal-dtc-short-range","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"Without disorder, a fast drive can still keep a time crystal alive for a time that grows exponentially with drive frequency, but theory says this needs long-range interactions or at least two dimensions. Existing observations used long-range or dipolar interactions.","posed_since":"2017","precise":"For a periodically driven spin lattice with short-range couplings of strength $J$, drive frequency $\\omega >> J/\\hbar$ and near-$\\pi$ spin flips, prethermal theory (Else, Bauer, Nayak, PRX 7, 011026, 2017) predicts period-doubled response lasting $t* \\sim \\mathrm{exp}(c \\hbar \\omega/J)$; at finite energy density this needs spontaneous breaking of an emergent Ising symmetry of the prethermal Hamiltonian, hence $d \\ge 2$ for short-range couplings. Does a $d = 2$ short-range system show t* growing exponentially with $\\omega$, and does the response vanish above the critical energy density of the prethermal Ising transition? Answer yes or no, with $t*(\\omega)$.","problem_ref":"a8b4857e61dbcfc526a2ad7e3847124ac6c5ba7d69b007e1ee9847bf1c439ac2","references":"","settled_by":"Measurement in a 2D Rydberg or superconducting-qubit array, or large-scale numerics, of the period-doubled lifetime versus $\\omega$ and initial energy density.","status_note":"Observed with long-range interactions in a trapped-ion chain (Kyprianidis et al., Science 2021) and with dipolar couplings in 3D nuclear-spin ensembles (Beatrez et al., Nature Physics 2023; Stasiuk et al., PRX 2023); a 2D short-range test is not known (low confidence).","title":"Prethermal time crystal in a clean short-range two-dimensional lattice","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"0776ef4c244bcd21e1b849694b91655ce421f7a88f5b5848536b99f4d6ecbccc","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"0a8eed0ed3b5c910ab07d1728f537e110231c95a20bc6196b9bf7bcaf3e4d7c0","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"4TDWM_xyhZF6pZi2kssCXJzFzqGozYdKHRs7QqcTQQEfVYt_C8lCZjxXhjDdRPnjNMCAScSjPvffA1aabUsIAA"},"schema":"pubphys.envelope/1"},"record_hash":"0776ef4c244bcd21e1b849694b91655ce421f7a88f5b5848536b99f4d6ecbccc","leaf_index":2808}