{"paper":{"title":"Nonlinear dynamic elastic moduli from equilibrium stress fluctuations","license":"http://creativecommons.org/licenses/by/4.0/","headline":"Equilibrium stress fluctuations determine the nonlinear dynamic elastic moduli.","cross_cats":["cond-mat.stat-mech"],"primary_cat":"cond-mat.mtrl-sci","authors_text":"F. E. Garbuzov, Y. M. Beltukov","submitted_at":"2026-05-13T15:52:40Z","abstract_excerpt":"Fluctuation formulas for elastic and viscoelastic moduli allow their computation from equilibrium molecular dynamics simulations, avoiding explicit nonequilibrium deformation protocols. While such expressions are well established for the quasi-static moduli, and also the linear dynamic moduli, no fluctuation formula exists for the nonlinear time-dependent moduli that govern anharmonic viscoelastic response under finite time-dependent strains. In this work we derive transient-time correlation function expressions for both the linear and the nonlinear dynamic moduli, starting from the DOLLS/SLLO"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"no fluctuation formula exists for the nonlinear time-dependent moduli that govern anharmonic viscoelastic response under finite time-dependent strains. In this work we derive transient-time correlation function expressions for both the linear and the nonlinear dynamic moduli, starting from the DOLLS/SLLOD equations of motion for irrotational motion.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The derivation assumes that the DOLLS/SLLOD equations of motion for irrotational motion correctly capture the nonlinear response and that equilibrium time correlations of the stress tensor and Born-kinetic terms suffice to express the finite-strain dynamic moduli.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Derivation of equilibrium fluctuation formulas for both linear and nonlinear time-dependent elastic moduli using DOLLS/SLLOD equations of motion.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Equilibrium stress fluctuations determine the nonlinear dynamic elastic moduli.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"ca183f15b5e7680d6a3cdb986e4d840898b64cef0df7a323b7499c3db16c7198"},"source":{"id":"2605.13703","kind":"arxiv","version":1},"verdict":{"id":"d7ffa92d-b081-463d-8df0-8cb5f1d8f3c3","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-14T17:46:29.519075Z","strongest_claim":"no fluctuation formula exists for the nonlinear time-dependent moduli that govern anharmonic viscoelastic response under finite time-dependent strains. In this work we derive transient-time correlation function expressions for both the linear and the nonlinear dynamic moduli, starting from the DOLLS/SLLOD equations of motion for irrotational motion.","one_line_summary":"Derivation of equilibrium fluctuation formulas for both linear and nonlinear time-dependent elastic moduli using DOLLS/SLLOD equations of motion.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The derivation assumes that the DOLLS/SLLOD equations of motion for irrotational motion correctly capture the nonlinear response and that equilibrium time correlations of the stress tensor and Born-kinetic terms suffice to express the finite-strain dynamic moduli.","pith_extraction_headline":"Equilibrium stress fluctuations determine the nonlinear dynamic elastic moduli."},"references":{"count":23,"sample":[{"doi":"","year":1982,"title":"Strain fluctuations and elastic constants,","work_id":"789e5a1f-df37-4f91-930b-06cba778d151","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1985,"title":"Molecular dynamics calculation of elastic constants for a crystalline system in equilibrium,","work_id":"b46da536-7f95-4f55-86d1-629f2d0272bf","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1989,"title":"Generalized expressions for the calculation of elastic constants by computer simulation,","work_id":"5b3a6929-e353-42fc-b4e7-e4d11436168c","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1969,"title":"Isothermal elastic constants for argon. 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