{"paper":{"title":"In situ estimation of local acoustic pressure amplitude by force balancing with a ferrofluid droplet probe","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","headline":"","cross_cats":[],"primary_cat":"cond-mat.mtrl-sci","authors_text":"Akira Nagakubo, Norikazu Nishiyama, Seiya Usui, Yoshiaki Uchida","submitted_at":"2026-05-22T06:39:25Z","abstract_excerpt":"Acoustic tweezers enable non-contact manipulation of microscale objects, but quantitative in situ evaluation of the peak local pressure amplitude remains difficult in confined devices. Conventional hydrophone-based measurements are often limited at the microscale by probe size and installation constraints. Here, we present a force-balance method in which a trapped ferrofluid droplet serves as a local probe in a standing-wave acoustic field and an externally applied magnetic-field gradient is tuned so that the magnetic force balances the maximum primary acoustic radiation force on the droplet. "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2605.23279","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2605.23279/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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"}