{"paper":{"title":"Decoherence-free subspaces in the noisy dynamics of discrete-step quantum walks in a photonic lattice","license":"http://creativecommons.org/licenses/by/4.0/","headline":"Certain bulk states in quantum walks stay coherent under constant noise while topological edge states decohere.","cross_cats":["cond-mat.dis-nn","physics.optics"],"primary_cat":"quant-ph","authors_text":"Alberto Amo, \\'Alvaro G\\'omez-Le\\'on, Cl\\'ement Hainaut, Rajesh Asapanna","submitted_at":"2025-10-17T20:35:14Z","abstract_excerpt":"We study the noisy dynamics of periodically driven, discrete-step quantum walks in a one-dimensional photonic lattice. We find that in the bulk, temporal noise that is constant within a Floquet period leads to decoherence-free momentum subspaces, whereas fully random noise destroys coherence in a few time steps. When considering topological edge states, we observe decoherence no matter the type of temporal noise. To explain these results, we derive a non-perturbative master equation to describe the system's dynamics. We experimentally confirm our findings in a time multiplexed photonic lattice"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"a class of bulk states can be more robust to a certain type of noise than topological edge states.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The temporal noise remains constant within each Floquet period, which is the condition stated for the appearance of decoherence-free momentum subspaces in the bulk.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Temporal noise constant within Floquet periods creates decoherence-free subspaces in bulk states of photonic quantum walks but destroys coherence in random noise cases and in topological edge states, as derived via a non-perturbative master equation and confirmed in a fiber-ring experiment.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Certain bulk states in quantum walks stay coherent under constant noise while topological edge states decohere.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"84b3292cb5e12b1587f1192c4c2e66cad25b48b87ae8c32d35d2edaad54564b5"},"source":{"id":"2510.16204","kind":"arxiv","version":2},"verdict":{"id":"721a9376-f30b-41d6-a092-5571fab645fd","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-18T05:42:51.887185Z","strongest_claim":"a class of bulk states can be more robust to a certain type of noise than topological edge states.","one_line_summary":"Temporal noise constant within Floquet periods creates decoherence-free subspaces in bulk states of photonic quantum walks but destroys coherence in random noise cases and in topological edge states, as derived via a non-perturbative master equation and confirmed in a fiber-ring experiment.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The temporal noise remains constant within each Floquet period, which is the condition stated for the appearance of decoherence-free momentum subspaces in the bulk.","pith_extraction_headline":"Certain bulk states in quantum walks stay coherent under constant noise while topological edge states decohere."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2510.16204/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":2,"snapshot_sha256":"75e23aea4312b08d41f386c2eb9e3a699842e13ee9bf4d10d7bbee9e5bfb447a"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}