{"paper":{"title":"Effects of Two Energy Scales in Weakly Dimerized Antiferromagnetic Quantum Spin Chains","license":"","headline":"","cross_cats":[],"primary_cat":"cond-mat.str-el","authors_text":"A. Br\\\"uhl, A. Kl\\\"umper, B. Rahaman, B. Wolf, C. Gross, M. Anton, M. Lang, R. Valenti, S. Glocke, T. Saha-Dasgupta, V. Pashchenko, W. Assmus","submitted_at":"2007-03-16T10:26:35Z","abstract_excerpt":"By means of thermal expansion and specific heat measurements on the high-pressure phase of (VO)$_2$P$_2$O$_7$, the effects of two energy scales of the weakly dimerized antiferromagnetic $S$ = 1/2 Heisenberg chain are explored. The low energy scale, given by the spin gap $\\Delta$, is found to manifest itself in a pronounced thermal expansion anomaly. A quantitative analysis, employing T-DMRG calculations, shows that this feature originates from changes in the magnetic entropy with respect to $\\Delta$, $\\partial S^{m}/ \\partial \\Delta$. This term, inaccessible by specific heat, is visible only i"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"cond-mat/0703431","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}