{"id":"c667cdb9-201e-426a-99b3-81a5d862b8e4","arxiv_id":"2605.29201","paper_version":1,"verdict":"UNVERDICTED","confidence":"LOW","novelty_score":6.0,"correctness_risk":"unknown","formal_verification":"none","parameter_count":0,"one_line_summary":"Extends perturbative framework to compute partial entropy production rate for active Ornstein-Uhlenbeck and run-and-tumble particles in harmonic potentials, reproducing an exact result and deriving a new expression.","lead":"This paper extends a perturbative framework to calculate partial entropy production for active particles with hidden self-propulsion states inside confining potentials. A smart generalist might read it to learn how to detect time-reversal asymmetry in partially observed non-equilibrium systems like molecular motors or swimming cells.","discovery_kind":"extension","skeptic_critique":{"model":"grok-4.3","headline":"Validity of applying the 2026 PRL perturbative framework to hidden self-propulsion dynamics in confining potentials","rationale":"The reader's weakest_assumption pinpoints the precise point at which the argument is least secure. Because the original review had access only to the abstract, the same assumption remains the load-bearing step even after the full text is consulted; no other internal inconsistency is visible from the stated claims.","tokens_in":1610,"tokens_out":289,"duration_ms":20229,"concrete_test":"Re-derive the partial entropy production rate for the harmonic RTP case from the perturbative equations in the full manuscript and compare the resulting closed-form expression against an independent numerical estimate obtained by simulating long trajectories of the RTP in the same harmonic trap and computing the empirical time-reversal asymmetry; agreement within sampling error would support the extension.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim requires that the perturbative construction from the cited PRL remains valid and accurate once the self-propulsion is treated as a hidden Markov process and the particle is placed in a generic confining potential (including the harmonic case used for validation). The abstract asserts that the extension reproduces the known exact AOUP result and yields a new RTP expression, but this hinges on the perturbation capturing the relevant time-reversal asymmetry without additional non-perturbative corrections arising from the hidden-state switching or from the potential-induced steady-state measure.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.3","summary":"The manuscript extends the perturbative framework from Phys. Rev. Lett. 136, 198302 (2026) to compute the partial entropy production rate quantifying time-reversal asymmetry for a generic active particle with hidden self-propulsion in a generic confining potential. In the harmonic potential, the framework is shown to reproduce the known exact result for an active Ornstein-Uhlenbeck particle and to yield a new expression for the run-and-tumble particle.","tokens_in":1736,"tokens_out":329,"duration_ms":19832,"significance":"If the central extension holds, the work supplies a practical perturbative route to partial entropy production in partially observed active systems, which is relevant for connecting theory to experiments where propulsion is hidden. The explicit reproduction of the exact AOUP result in the harmonic case provides a non-trivial validation that the perturbative construction captures the relevant asymmetry without additional corrections from the hidden-state dynamics or the potential.","major_comments":[],"minor_comments":[{"comment":"The abstract states that the framework 'reproduces an exact result' for AOUP but does not indicate the numerical or analytic tolerance of the match; adding a brief statement or reference to the relevant comparison (e.g., in the harmonic-case section) would strengthen the validation claim.","section":null},{"comment":"Notation for the hidden self-propulsion process (Markov switching rates, observation map) is introduced without an explicit comparison table to the original PRL framework; a short table or paragraph clarifying which elements are carried over unchanged would improve readability.","section":null}],"recommendation":"minor_revision","confidential_remarks":null},"author_rebuttal":{"model":"grok-4.3","summary":"We thank the referee for their positive summary and recommendation of minor revision. No specific major comments were provided in the report, so we have no points requiring point-by-point response. The validation against the exact AOUP result is already included in the manuscript as a non-trivial check.","responses":[],"tokens_in":1110,"tokens_out":74,"duration_ms":9695,"standing_objections":[]},"desk_editor":{"model":"grok-4.3","letter":"The central advance is taking the existing perturbative construction and showing it can handle a hidden Markov process for the self-propulsion inside a confining potential. They focus on the harmonic case, recover the exact AOUP partial entropy production, and produce an explicit expression for the run-and-tumble particle that was not available before.\n\nThe reproduction of the exact AOUP result is the strongest part of the work. It indicates that the perturbation captures the visible time-reversal asymmetry even when the driving is hidden, at least for that model. Treating the hidden state as part of the joint dynamics and then projecting appears to be a workable route.\n\nThe main soft spot is the dependence on the perturbative framework remaining accurate once the self-propulsion switches and the potential shapes the steady-state measure. The abstract claims the extension works without extra non-perturbative corrections, but the strength of that claim rests on the details of how they implement the hidden-state averaging and any truncation order. Without explicit error bounds or tests away from the harmonic trap, it is difficult to judge the practical range.\n\nA secondary point is the direct build on the 2026 PRL; the new RTP result is presented as independent, yet any unexamined overlap in assumptions could affect how standalone the derivation feels.\n\nThis is a technical tool paper for people already working on entropy production in active systems with incomplete observations. It does not change the broader picture but supplies a calculational step that some groups will want to use or extend.\n\nI would send it to peer review so the derivations and the limits of the perturbation can be checked properly.","headline":"The paper extends the 2026 PRL perturbative method to hidden self-propulsion and derives a new partial entropy production rate for run-and-tumble particles in harmonic traps while matching the known AOUP result.","tokens_in":2186,"tokens_out":407,"would_cite":false,"duration_ms":27601,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.3","headline":"A perturbative framework calculates the partial entropy production of active particles with hidden self-propulsion in generic confining potentials.","keywords":["partial entropy production","active particles","hidden states","confining potentials","Ornstein-Uhlenbeck process","run-and-tumble motion","time-reversal asymmetry","perturbation theory"],"falsifier":"A direct numerical simulation or exact analytic calculation of the partial entropy production rate for a run-and-tumble particle in a harmonic potential that yields a numerical value different from the perturbative expression derived in the paper.","tokens_in":2511,"feed_emoji":"","tokens_out":667,"duration_ms":33114,"temperature":0.7,"pith_summary":"This paper extends an existing perturbative method to compute the partial entropy production rate for active particles whose self-propulsion is hidden from direct observation. The rate quantifies the time-reversal asymmetry that remains visible in the observed particle trajectories even when the full dynamics operate far from equilibrium. The extension applies to any generic confining potential. In the harmonic potential the same method recovers the exact known result for the active Ornstein-Uhlenbeck particle and supplies an explicit expression for the run-and-tumble particle. A reader would care because many experimental tracks of active matter are only partially observed, and the framework offers a route to extract the hidden irreversibility without reconstructing the full state.","feed_headline":"Method calculates partial entropy production of hidden active particles","feed_subtitle":"The perturbative extension applies to generic confining potentials and recovers exact results for the active Ornstein-Uhlenbeck particle whi","key_machinery":"The perturbative framework for partial entropy production, extended from the cited PRL paper and applied to the hidden self-propulsion dynamics inside a confining potential.","core_discovery":"The perturbative framework can be extended to calculate the partial entropy production in a generic confining potential for a generic active particle with hidden self-propulsion, and in the harmonic case it reproduces the exact result for an active Ornstein-Uhlenbeck particle while deriving the rate for a run-and-tumble particle.","pith_inferences":["The same perturbative construction could be tested against simulations of active particles in anharmonic or time-dependent potentials.","Experimental trajectories of colloidal or biological active particles could be analyzed with this method to bound the hidden propulsion strength without full state reconstruction.","If the framework generalizes, it may separate the entropy-production contribution of hidden variables from the observed motion in a wider class of partially observed stochastic systems."],"forward_implications":["The partial entropy production rate becomes accessible for arbitrary confining potentials through the extended perturbative approach.","The framework recovers the exact partial entropy production rate for the active Ornstein-Uhlenbeck particle in the harmonic potential.","An explicit expression for the partial entropy production rate of the run-and-tumble particle is obtained in the harmonic potential."],"fun_headline_variants":["Perturbative extension for partial entropy in hidden active particles","Partial entropy production calculated in confining potentials","Partial entropy rates for active Ornstein-Uhlenbeck in harmonics","Framework derives partial entropy for run-and-tumble particles"],"cache_read_input_tokens":2112,"weakest_assumption_plain":"The perturbative framework introduced in the 2026 PRL paper remains valid and accurate when applied to active particles with hidden self-propulsion in confining potentials, including the harmonic case.","fun_headline_variants_meta":{"raw":{"variants":["Perturbative extension for partial entropy in hidden active particles","Partial entropy production calculated in confining potentials","Partial entropy rates for active Ornstein-Uhlenbeck in harmonics","Framework derives partial entropy for run-and-tumble particles"]},"model":"grok-4.3","cost_usd":0.009037,"raw_usage":{"total_tokens":3989,"prompt_tokens":533,"num_sources_used":0,"completion_tokens":62,"cost_in_usd_ticks":90374500,"prompt_tokens_details":{"text_tokens":533,"audio_tokens":0,"image_tokens":0,"cached_tokens":256},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":3394,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":533,"tokens_out":62,"duration_ms":27591,"temperature":1.0,"reasoning_tokens":3394,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-06-29T01:06:57.309767+00:00","model_set":{"reader":"grok-4.3"},"falsifier":"A direct numerical simulation or exact analytic calculation of the partial entropy production rate for a run-and-tumble particle in a harmonic potential that yields a numerical value different from the perturbative expression derived in the paper.","supporting_citations":[],"review_version":1}