{"id":"ea69cec2-18f8-41b6-8c94-4f12ed9cba0e","arxiv_id":"2508.05768","paper_version":1,"verdict":"UNVERDICTED","confidence":"LOW","novelty_score":5.0,"correctness_risk":"unknown","formal_verification":"none","parameter_count":0,"one_line_summary":"Adding passive particles to a phase-separated active suspension can produce a stable, self-sustained drift of the dense slab.","lead":"This paper simulates a dense suspension of self-propelled particles with a small number of ordinary Brownian particles mixed in. It finds that the dense slab can develop stable propagating interfaces and drift over long times, a behavior not seen in purely active systems.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Full text is an unrelated quantum-compiler paper; the MIPS slab-propagation claim has no presented methods, controls, or analysis.","rationale":"The reader's UNVERDICTED verdict is correct. The abstract describes a plausible soft-matter study, but the supplied full text is an unrelated quantum computing paper, so none of the methods, parameter choices, numerical results, or reproducibility details are available. The reader's weakest assumption identifies the causal role of passive-particle depletion as the key scientific premise; this is the same load-bearing concern, and it is untestable from the current manuscript. We are not accusing the authors of misconduct; we are reporting an internal inconsistency in the submitted text. The proposed check would settle the concern by recovering the true full text and, if it exists, performing a minimal control simulation or verifying that such controls are already present. Since the reader already marked the paper UNVERDICTED, no change to the verdict is needed.","tokens_in":6301,"tokens_out":3281,"duration_ms":35081,"concrete_test":"Retrieve the actual arXiv:2508.05768 source via the arXiv API and verify the full text contains: (a) a simulation/model section specifying ABP and passive-particle parameters, box geometry, and boundary conditions; (b) average density profiles showing an asymmetric, steadily propagating slab interface; (c) control simulations with passive particles absent or uniformly distributed to test whether the depletion asymmetry is necessary for directed motion; and (d) analysis of fluctuation-induced reversal events. If any of these are absent, the central claim is unsupported. Independently, run a minimal computational check: simulate the same elongated periodic system with zero passive fraction and with a symmetric passive distribution; the slab interface velocity should vanish or change qualitatively if the depletion asymmetry is genuinely causal.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The abstract claims a new dynamical regime: in a passive-active ABP mixture, the dense slab formed by MIPS exhibits stable, directed interface propagation because passive particles are depleted on one side, and this is a self-sustained combination of source/sink and rigid displacement effects. For this claim to hold, the mechanism must be causal, not merely correlated with drift. The manuscript as supplied, however, is an unrelated quantum error-correction compiler paper (ConiQ, arXiv:2508.05779v1). The body contains no mention of active Brownian particles, motility-induced phase separation, passive dopants, density profiles, interface asymmetry, or fluctuation/reversal statistics. Every load-bearing element of the abstract's argument is therefore missing: (i) the model definition (system size, activity, passive fraction, boundary conditions), (ii) the average density profile calculations showing asymmetric interfaces and steady propagation, (iii) control simulations without passive particles or with symmetric depletion to establish that the depletion asymmetry is causal, and (iv) the analysis of fluctuations that produce, cancel, and reverse motion. This is an internal inconsistency between the abstract and the full text, not merely a disagreement with scientific consensus. The central claim is currently unfalsifiable from the available material; the reader's weakest assumption about causality of the depletion asymmetry is exactly the point that cannot be checked.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The manuscript (arXiv:2508.05768) presents an abstract claiming a new dynamical regime in a 2D suspension of active Brownian particles with a small fraction of passive Brownian particles: the dense slab formed by motility-induced phase separation (MIPS) can develop a stable, directed propagation of its interfaces over long times, driven by depletion of passive particles on one side. The authors state that the motion is not purely a source/sink effect nor a rigid displacement, but a self-sustained combination of both, and that average density profile calculations reveal an asymmetry between the two interfaces, with specific fluctuations producing, cancelling, and reversing the motion. However, the supplied full text is not this paper at all: it is the manuscript 'ConiQ: Enabling Concatenated Quantum Error Correction on Neutral Atom Arrays' (arXiv:2508.05779v1), a quantum compilation paper. None of the active-matter methods, simulations, or analyses described in the abstract appear in the body.","tokens_in":6556,"tokens_out":5160,"duration_ms":54558,"significance":"If the claimed effect is real, it would be a significant contribution to active-matter physics: it identifies a new self-sustained traveling state in a passive-active mixture, with a proposed mechanistic decomposition into source/sink and coherent displacement contributions, and a concrete asymmetry signature. Such a result would be interesting for the dynamics of MIPS interfaces and for designing active suspensions with controllable transport. The manuscript as supplied, however, provides no evidence for any of this. There are no model definitions, simulation parameters, control experiments, density profiles, or fluctuation analyses; there are no machine-checked proofs, reproducible code, or falsifiable quantitative predictions. The significance cannot be assessed beyond the level of the abstract's brief claim.","major_comments":[{"comment":"The full text supplied for this submission is an unrelated quantum-computing paper (ConiQ, arXiv:2508.05779v1). The body contains no mention of active Brownian particles, motility-induced phase separation, passive dopants, density profiles, interface asymmetry, or slab propagation. Every load-bearing element claimed in the abstract—model definition, density profile calculations, kinetic analysis, fluctuation and reversal statistics—is absent. This is an internal inconsistency between the abstract and the manuscript body, not a disagreement with scientific consensus.","section":"Abstract; full text Sections I–IX"},{"comment":"The abstract attributes the slab propagation to 'symmetry breaking caused by the depletion of passive particles on one side of the slab.' No evidence is presented that this depletion asymmetry is causal rather than a correlated consequence of drift. In particular, no control simulations are reported with passive particles absent, with symmetric depletion, or with reversed initial conditions. The central mechanism is therefore not established.","section":"Abstract"},{"comment":"The claimed quantitative support—average density profiles, interface asymmetry, decomposition into source/sink and rigid displacement, and the specific fluctuations that produce, cancel, or reverse motion—is entirely missing from the supplied text. No system size, aspect ratio, activity, passive fraction, boundary conditions, time scales, error bars, or numerical methods are given. The claimed regime is unfalsifiable from the available material.","section":"Abstract, 'average density profile calculations'"}],"minor_comments":[{"comment":"The title contains a typo: 'Peparation' should be 'Separation'.","section":"Title (arXiv listing)"}],"recommendation":"reject","confidential_remarks":"The supplied full text is a different manuscript from the one described in the abstract. Whatever the cause, the submission as it stands is not reviewable because the body does not address the claimed topic. I recommend handling this as a desk rejection/return to the authors; if the correct MIPS manuscript is available, it should be submitted as a new version with full simulation details."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Colleague,\n\nThe punchline: the thing you get when you open this arXiv page is not the paper the abstract describes. The abstract is a soft-matter simulation study of doped active Brownian particles and self-sustained slab propagation in MIPS. The full text is an unrelated quantum compiler paper (ConiQ, arXiv:2508.05779v1). There is no density profile, no ABP model, no passive fraction, no control simulation, nothing. So there is no paper to referee, only an abstract.\n\nOn the abstract's own terms, it is plausible and clearly written. The claim — that adding a small fraction of passive Brownian particles to a 2D active suspension can give the MIPS dense slab a steady, self-sustained interface propagation that is neither pure source/sink nor rigid displacement — is a genuinely interesting dynamical state if it holds. The wording suggests the authors have done density-profile and kinetic analyses, and the attention to fluctuation-driven reversals is a good sign. That is real value, but it is value in the abstract alone.\n\nThe soft spots are not subtle. Because the body is mismatched, every load-bearing element is missing: model parameters, boundary conditions, verification of steady propagation, and especially the causality claim. The abstract attributes the motion to depletion of passive particles on one side. That is a mechanism claim. Without control simulations (no passive particles, symmetric depletion) or at least a parameter study, the depletion could easily be a correlate rather than the cause. And the reader's point about system-size dependence of 'long periods of time' is exactly the kind of thing that needs simulation details.\n\nOn the citation pattern and self-citation: irrelevant here, because we cannot see the actual references for this work.\n\nBottom line: this submission is internally inconsistent at the level of metadata. It is unfalsifiable from the supplied material, not because the science is bad but because the full text is a different paper. Whoever is at the desk should return it and ask for the correct manuscript. If the real paper matches that abstract, it might well deserve a serious referee — but this version does not, and I would not send it out in this state.","headline":"The full text is an unrelated quantum-compiler paper, so there is no actual MIPS manuscript to referee; the abstract alone is plausible but unverifiable.","tokens_in":7002,"tokens_out":1658,"would_cite":false,"duration_ms":17177,"reading_group":"no","serious_thinker":"no","would_accept_peer_review":false},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"This paper claims that a small admixture of passive Brownian particles turns the stationary dense slab of a phase-separated active suspension into a self-sustained travelling structure.","keywords":["motility-induced phase separation","active Brownian particles","passive-active mixture","dense slab propagation","symmetry breaking","interface dynamics","self-sustained motion"],"falsifier":"Simulate the same passive-active mixture in a periodic rectangular box but with passive particles artificially replenished on the depleted side, or with a symmetric bimodal passive distribution; if the steady directed propagation persists, the depletion asymmetry is not the cause. Alternatively, measure the slab velocity as a function of the passive fraction: the proposed mechanism predicts a nonmonotonic dependence that vanishes both at zero and at large passive fractions.","tokens_in":6223,"feed_emoji":"🌀","tokens_out":3746,"duration_ms":37746,"temperature":0.7,"pith_summary":"Adding a small number of passive (non-self-propelled) Brownian particles to a two-dimensional suspension of repulsive active Brownian particles does not destroy motility-induced phase separation, but it changes the dynamics of the resulting dense phase. In an elongated box, the dense slab's two interfaces can propagate steadily in one direction for long periods, an effect the authors attribute to the depletion of passive particles on one side of the slab, which breaks left-right symmetry. Using average density profiles and a kinetic decomposition, the paper shows that the apparent slab motion is neither pure evaporation/condensation nor pure rigid translation, but a self-sustained combination of both. The authors also analyze fluctuations that produce, cancel, and abruptly reverse the motion. If correct, the paper establishes a new dynamical regime in doped active matter in which a phase boundary moves without any external drive.","feed_headline":"Passive dopants set an active dense slab marching","feed_subtitle":"In a passive-active suspension, the dense phase's interfaces propagate steadily for long times, no external forcing needed.","key_machinery":"The central object is the dense slab of active particles in a passive-active mixture, with the passive particles acting as an asymmetric reservoir. The mechanism is the depletion of passive particles on one side of the slab, which breaks the left-right symmetry of the two interfaces and sustains a net flux of active particles through the slab. The kinetic analysis decomposes the interface velocity into a source/sink part and a rigid-translation part, demonstrating that the motion is a self-sustained combination of both.","core_discovery":"The paper claims that passive Brownian particles added to a repulsive active Brownian suspension preserve motility-induced phase separation, but in elongated geometries the dense slab is not static: over long periods it exhibits stable, well-defined propagation of both interfaces. The mechanism proposed is the depletion of passive particles on one side of the slab, creating a symmetry breaking that sustains the motion. The slab movement is not a pure source/sink effect (active particles evaporating from one interface and condensing onto the other) nor a rigid displacement of all particles, but a self-sustained combination of the two. Average density profiles reveal an asymmetry between the t","pith_inferences":["The same depletion-asymmetry mechanism might be used to transport the dense phase across a channel, with the passive fraction acting as a steering parameter.","Because the effect relies on a long-lived asymmetry, it may be sensitive to box length and total density; varying those could reveal a transition between static and propagating slabs.","The identified fluctuation modes that reverse motion could be harnessed or suppressed by engineering the passive-particle concentration or activity."],"forward_implications":["Small passive fractions do not destroy motility-induced phase separation but alter its coarsening dynamics.","The dense active phase can be made to travel without external forcing by exploiting depletion asymmetry.","The slab velocity decomposes into measurable source/sink and drift contributions, enabling quantitative comparison with theory.","Fluctuation-driven reversals mean that the direction of motion is not fixed and may be controllable."],"supporting_citations":[],"fun_headline_variants":["Passive dopants trigger steady interface motion in active slab","Doped active mixtures show self-sustained slab movement","Depletion asymmetry drives active dense phase to march","Active slab self-propels via passive particle depletion"],"cache_read_input_tokens":2816,"weakest_assumption_plain":"The claim that slab motion is caused by the depletion of passive particles on one side assumes that the depletion asymmetry is the driving mechanism and not just a side effect; if the asymmetry were absent or the cause were something else, the propagating-slab regime would not be the robust phenomenon described.","fun_headline_variants_meta":{"raw":{"variants":["Passive dopants trigger steady interface motion in active slab","Doped active mixtures show self-sustained slab movement","Depletion asymmetry drives active dense phase to march","Active slab self-propels via passive particle depletion"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000529,"raw_usage":{"total_tokens":2356,"prompt_tokens":680,"completion_tokens":1676,"prompt_tokens_details":{"cached_tokens":256},"prompt_cache_hit_tokens":256,"prompt_cache_miss_tokens":424,"completion_tokens_details":{"reasoning_tokens":1613}},"tokens_in":424,"tokens_out":1676,"duration_ms":12210,"temperature":1.0,"reasoning_tokens":1613,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-05T23:08:36.492994+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Simulate the same passive-active mixture in a periodic rectangular box but with passive particles artificially replenished on the depleted side, or with a symmetric bimodal passive distribution; if the steady directed propagation persists, the depletion asymmetry is not the cause. Alternatively, measure the slab velocity as a function of the passive fraction: the proposed mechanism predicts a nonmonotonic dependence that vanishes both at zero and at large passive fractions.","supporting_citations":[],"review_version":1}