{"paper":{"title":"Wall accumulation of confined active Janus colloids due to effective active diffusivity","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Active Janus colloids confined between parallel walls accumulate at the boundaries because persistent stochastic turning about a small out-of-plane angle generates an effective cross-channel drift and diffusion.","cross_cats":["cond-mat.stat-mech"],"primary_cat":"cond-mat.soft","authors_text":"Alicia Boymelgreen, Jarrod Schiffbauer, Sandeep Ramteke","submitted_at":"2026-05-13T01:09:41Z","abstract_excerpt":"Electrokinetically-driven Janus colloids, e.g., with one metallic and one dielectric hemisphere, confined between parallel walls exhibit a boundary-accumulation mechanism enabled by an effective cross-channel diffusivity which is distinct from wall accumulation of active Brownian or run-andtumble particles. Using density-matched suspensions and three-dimensional confocal imaging, we directly measure the full time-dependent redistribution of particles across the channel under an applied AC electric field. The wall population grows exponentially while the bulk depletes, and data obtained over mu"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"Persistent stochastic turning about a small out-of-plane angle results in a cross-channel effective drift and diffusion. The drift governs the dominant timescale and the diffusion is strong enough to provide significant accumulation on the bottom wall despite a mean upward orientational bias.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the orientation dynamics are accurately captured by an overdamped Ornstein-Uhlenbeck turning process with a small mean out-of-plane angle, allowing the effective cross-channel drift and diffusion to be derived directly from the measured relaxation rate without additional free parameters.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Confined electrokinetically driven Janus colloids accumulate at walls via effective active diffusivity from persistent out-of-plane stochastic turning, producing exponential wall-population growth and single-timescale data collapse.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Active Janus colloids confined between parallel walls accumulate at the boundaries because persistent stochastic turning about a small out-of-plane angle generates an effective cross-channel drift and diffusion.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"db9c0faa79f6a936ae1642c8ad156d5836e8c54946017f4b13d85933af655dd2"},"source":{"id":"2605.12860","kind":"arxiv","version":1},"verdict":{"id":"a548b4f9-8d28-4e28-8152-179a75dd7237","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-14T18:56:24.687343Z","strongest_claim":"Persistent stochastic turning about a small out-of-plane angle results in a cross-channel effective drift and diffusion. The drift governs the dominant timescale and the diffusion is strong enough to provide significant accumulation on the bottom wall despite a mean upward orientational bias.","one_line_summary":"Confined electrokinetically driven Janus colloids accumulate at walls via effective active diffusivity from persistent out-of-plane stochastic turning, producing exponential wall-population growth and single-timescale data collapse.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the orientation dynamics are accurately captured by an overdamped Ornstein-Uhlenbeck turning process with a small mean out-of-plane angle, allowing the effective cross-channel drift and diffusion to be derived directly from the measured relaxation rate without additional free parameters.","pith_extraction_headline":"Active Janus colloids confined between parallel walls accumulate at the boundaries because persistent stochastic turning about a small out-of-plane angle generates an effective cross-channel drift and diffusion."},"references":{"count":21,"sample":[{"doi":"","year":null,"title":"Here, U(E) is determined using the mobility, µ ICEP = 1","work_id":"cfbbe57c-8efa-4258-92a4-3478ae7845d9","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1977,"title":"E. M. Purcell, Life at low reynolds number, American Jour nal of Physics 45, 3 (1977). 10","work_id":"ac6f4d80-5fa0-4c3a-9fe6-4b5ba762ae50","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1999,"title":"W. Ebeling, F. Schweitzer, and B. Tilch, Active brownian particles with energy depots mod- eling animal mobility, BioSystems 49, 17 (1999)","work_id":"a5617aa7-00b2-4f76-934b-0e93e0364584","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2023,"title":"Z¨ ottl and H","work_id":"16777d8f-b64c-47a7-8d7d-d1252a91e2b2","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1972,"title":"H. C. Berg and D. A. Brown, Chemotaxis in Escherichia coli analysed by three-dimensional tracking, Nature 239, 500 (1972)","work_id":"c73927d5-53f8-4c18-b766-59a53a32ae11","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":21,"snapshot_sha256":"126c25e11aa0babd51862bef7f65af8d62f68d6e3f7c1dd4a2b81ccf87575c02","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"}