{"id":"9596b4f0-0c02-4193-ab32-ba1f54237c08","arxiv_id":"2607.03538","paper_version":1,"verdict":"CONDITIONAL","confidence":"HIGH","novelty_score":7.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":3,"one_line_summary":"Prominent solutions to the quantum screen problem yield mutually distinguishable arrival-position distributions for particles from single- and double-well traps, including in the far-field limit.","lead":"Different models of quantum detection by always-on screens predict different spatial hit patterns for atoms released from traps, and the differences survive even far from the source. Simple tabletop atom experiments could therefore decide which models work and expose limits of standard scattering theory.","discovery_kind":"extension","skeptic_critique":{"model":"grok-4.5","headline":"No significant objection identified beyond the paper’s own caveats on far-field rigor.","rationale":"The paper’s strongest empirical claim is that the six models produce distinguishable A_L(\theta) already at accessible L/\tau and that CAP/ABC/MS stay distinct from SC even as L\to\tau. That claim is supported by explicit finite-L plots (Figs. 2–3), by the analytically derived oblique-angle and scaling limits (Sections IV.C–D), and by released code. The sole mathematical caveat the authors themselves flag—the lack of a rigorous L1 proof for the far-field expressions—is precisely the reader’s weakest_assumption. Because that caveat is already priced into the CONDITIONAL verdict, and because no stronger internal inconsistency or unstated assumption that would invalidate the finite-L distinctions was found, the stress-test does not move the verdict. The recommended concrete check simply tightens the same numerical support the paper already offers.","tokens_in":22535,"tokens_out":523,"duration_ms":4879,"concrete_test":"Using the public repository, recompute A_L(\theta) for the single-well Gaussian at L=10^4 \tau and L=10^5 \tau (same CAP/ABC/MS parameters as Fig. 2) and check whether the L1 distance of each absorbing model to the SC curve continues to decrease while the \theta\to±\tau/2 limits remain 0 (absorbing) versus finite (SC/QF). If the qualitative separation collapses, the far-field claim weakens; otherwise the conjecture is further corroborated.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The reader’s weakest_assumption correctly flags the only soft spot that could affect the strongest claim: the far-field formulas (Eqs. 13–19) are labeled “numerically supported conjectures” whose L1 convergence is left open (Section IV.B). That caveat is already explicit, the finite-L numerics (Figs. 2–3, L=10^3 \\sigma) already display the claimed qualitative distinctions (oblique-angle limits, non-recovery of SC by CAP/ABC/MS), and the released code lets any reader recompute those plots. No additional load-bearing gap—mathematical inconsistency, hidden assumption that fails for the stated Gaussians, or unacknowledged detector-dependence that would erase the distinctions—appears. The central claim therefore stands on the same footing the authors and the reader already assign it.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.5","summary":"The paper formulates the arrival-position problem (the spatial marginal of the screen problem for always-on detectors) as complementary to the better-known arrival-time problem. It derives explicit angular distributions A_L(θ) for six standard proposals (semiclassical SC, quantum flux QF, Kijowski/standard SD, complex absorbing potential CAP, absorbing-boundary condition ABC, and Marchewka–Schuss MS) applied to single- and double-well Gaussian packets, supplies finite-L numerics for realistic atom-trap parameters, and obtains far-field formulas showing that CAP/ABC/MS remain distinguishable from the semiclassical limit even as L→∞. Feasible cold-atom experiments are outlined that can discriminate the models via total detection probability, oblique-angle tails, and scaling under wave-function dilation.","tokens_in":22805,"tokens_out":843,"duration_ms":15448,"significance":"If the distinctions hold, the work converts a long-standing foundational gap into a set of concrete, table-top falsifiable predictions that do not require time-resolved data. Strengths include fully explicit formulas for every model, open-source code that regenerates the figures, mass-independence of A_L for five of the six proposals, and clear experimental signatures (vanishing oblique density for absorbing models, 50 % detection probability for SC/QF/SD, non-trivial scaling of CAP/ABC/MS). These features make the paper immediately useful both for theorists refining screen models and for experimental groups already performing single-atom release-and-detect protocols.","major_comments":[{"comment":"§IV.B, Eqs. (13)–(19): the far-field expressions for CAP, ABC and MS are labelled “numerically supported conjectures” whose L^{1} convergence is left unproved. While the L = 10^{3}σ panels of Figs. 2–3 already display the claimed qualitative distinctions, a short appendix quantifying the L^{1} distance to the limiting formulas (or a reference to a rigorous stationary-phase argument under the stated Gaussian regularity) is needed before the persistence-as-L→∞ claim can be regarded as fully established.","section":null},{"comment":"§III.A and §IV.A: the quantum-flux proposal is applied only under the current-positivity condition, which the authors verify for the chosen Gaussians and L. A brief statement of the range of L/σ and well separations for which positivity continues to hold (or a note that the truncated-flux prescription of Ref. [12] would be used otherwise) would remove any ambiguity about the domain of the QF curves shown in the figures.","section":null}],"minor_comments":[{"comment":"Fig. 1 caption: the value λ = 2σ is given without units; since λ has dimensions of length it would be clearer to write “λ = 2σ (with σ = 1 µm)”.","section":null},{"comment":"Eq. (7): the angular density A_L is defined with an integral over z and τ; a parenthetical remark that the z-integral is trivial by separability would help readers who skip §III.B.","section":null},{"comment":"§IV.D, Fig. 4: the horizontal axis is labelled α while the caption speaks of “rescaling parameter α”; adding the explicit relation α = σ_new/σ_old would avoid momentary confusion.","section":null},{"comment":"References [105] and [111] are listed as 2026 arXiv preprints; if they have since been published, the journal citations should be updated.","section":null}],"recommendation":"minor_revision","confidential_remarks":"The manuscript is a clean, well-documented contribution that sits comfortably within quant-ph. The open-source code and the explicit experimental roadmap are genuine assets; I see no citation or novelty issues."},"author_rebuttal":null,"desk_editor":{"model":"grok-4.5","letter":"This paper does something useful: it takes the long-standing screen problem, isolates the arrival-position marginal that most double-slit-style data actually record, and shows that six standard proposals (SC, QF, SD, CAP, ABC, MS) give distinguishable angular distributions A_L(θ) for single- and double-well Gaussians that labs can already prepare. The far-field non-recovery of semiclassical scattering by CAP/ABC/MS (Eqs. 13–19), the oblique-angle classification via arrival-time tail exponents, and the spatial-rescaling diagnostics are new calculations, not rehashes of the arrival-time literature. Code is released; the numerics for realistic parameters (σ = 1 µm, L = 10σ and 10³σ) already display the claimed qualitative splits.\n\nWhat it does well is keep the free parameters (h, w, β, λ) as model inputs to be fixed by experiment rather than fitted, flag the current-positivity assumption for QF, and stay detector-agnostic enough that any “always-on” screen with one-outcome-per-trial structure falls inside the scheme. The mass-independence of most of the A_L predictions is a practical plus.\n\nThe soft spot is exactly the one the authors and the reader already name: the far-field formulas are labeled “numerically supported conjectures” whose L1 convergence is left open. That does not undercut the finite-L plots or the experimental distinguishability claim, but it means the infinite-L statements still need a proper proof. No hidden circularity or load-bearing math error shows up; the main real-world risk is simply that physical detectors may not realize any of the six idealizations.\n\nThis is for people who work on continuous measurement, arrival-time models, or cold-atom detection. It deserves a serious referee. I would bring it to reading group and expect to cite the comparison tables and far-field diagnostics.","headline":"Clean, usable conversion of the screen problem's position marginal into concrete, currently doable atom-trap experiments that already distinguish six models, including far-field deviations.","tokens_in":23337,"tokens_out":505,"would_cite":true,"duration_ms":4836,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.5","headline":"Six models for where a quantum particle hits a waiting screen make different, testable predictions even far away.","keywords":["arrival position","screen problem","quantum arrival time","quantum flux","absorbing boundary","complex absorbing potential","far-field scattering","atom traps"],"falsifier":"Prepare a ground-state single- or double-well atom, release it toward a light-sheet or microchannel-plate screen at known L/σ, accumulate hits without conditioning on detection, and check whether the measured A_L(θ) vanishes at large |θ|, diverges, or stays finite and flat—any of which immediately eliminates whole classes of proposals.","tokens_in":23461,"feed_emoji":"⚛️","tokens_out":872,"duration_ms":7329,"temperature":0.7,"pith_summary":"Standard quantum mechanics tells us how to predict the result of a position measurement done at a chosen instant, but it has no unambiguous rule for the places where particles are found by a detector that is simply left on until something clicks. This paper isolates that gap as the arrival-position problem and shows that six well-known proposals for solving it already disagree about the angular distribution of hits on a planar screen. The disagreements appear for ordinary single- and double-well atom traps, survive into the far-field regime where semiclassical scattering is usually trusted, and can be read off without recording precise arrival times. Because the contrasts are large enough for existing single-atom detection methods, the work turns a long-standing theoretical blind spot into a concrete experimental question.","feed_headline":"Where particles hit a waiting screen splits six quantum models","feed_subtitle":"Even far-field angular patterns disagree; atom traps can already decide among them","key_machinery":"The angular arrival-position density A_L(θ), obtained by integrating each joint screen distribution over time and the vertical coordinate and changing variables to the viewing angle θ from the origin; its far-field and oblique-angle limits, together with its response to spatial rescaling of the initial wave packet, serve as the diagnostic that separates the models.","core_discovery":"The six surveyed proposals (semiclassical, quantum flux, standard/Kijowski, complex absorbing potential, absorbing boundary condition, and Marchewka–Schuss path-integral absorption) produce mutually distinguishable angular arrival-position distributions for the same Gaussian single- and double-well initial states. Several of the differences remain even as the screen is moved to infinity, so they cannot be dismissed as near-field corrections.","pith_inferences":["If CAP, ABC or MS is correct, two identically placed screens of different physical makeup must produce measurably different far-field angular patterns—an immediate, detector-level test the paper only hints at.","The same angular diagnostics can be applied to any future screen-problem proposal simply by computing its γ_tail; the paper thereby supplies a quick filter that later models must pass.","Because most of the distributions are mass-independent, the same spatial experiment can be repeated with different atomic species to isolate the one mass-dependent model (CAP) without new apparatus."],"forward_implications":["Table-top atom-trap experiments can already decide among leading screen-problem proposals by looking only at hit positions, not times.","Agreement with standard scattering theory at all angles forces a precise 1/τ² tail on the arrival-time distribution; any other tail exponent is ruled out.","Detector models that remain non-semiclassical in the far field must retain a detectable dependence on screen composition even at large L.","Rescaling the trap width while holding detector parameters fixed changes total detection probability for absorbing models but leaves the semiclassical, flux, and standard predictions invariant."],"fun_headline_variants":["Six quantum models split on where particles hit a waiting screen","Arrival positions diverge across six models even in far field","Waiting detectors reveal angular arrival splits among six theories","Far-field screen hits distinguish six quantum arrival proposals","Particle landings on a screen expose six mutually distinct models"],"cache_read_input_tokens":16512,"weakest_assumption_plain":"The far-field formulas that separate the models are treated as numerically supported conjectures whose rigorous L1 convergence is left for later work.","fun_headline_variants_meta":{"raw":{"variants":["Six quantum models split on where particles hit a waiting screen","Arrival positions diverge across six models even in far field","Waiting detectors reveal angular arrival splits among six theories","Far-field screen hits distinguish six quantum arrival proposals","Particle landings on a screen expose six mutually distinct models"]},"model":"grok-4.5","effort":"low","cost_usd":0.004702,"raw_usage":{"total_tokens":1303,"prompt_tokens":683,"num_sources_used":0,"completion_tokens":79,"cost_in_usd_ticks":47020000,"prompt_tokens_details":{"text_tokens":683,"audio_tokens":0,"image_tokens":0,"cached_tokens":256},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":541,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":683,"tokens_out":79,"duration_ms":4127,"temperature":1.0,"reasoning_tokens":541,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-07-12T01:45:47.141646+00:00","model_set":{"reader":"grok-4.5"},"falsifier":"Prepare a ground-state single- or double-well atom, release it toward a light-sheet or microchannel-plate screen at known L/σ, accumulate hits without conditioning on detection, and check whether the measured A_L(θ) vanishes at large |θ|, diverges, or stays finite and flat—any of which immediately eliminates whole classes of proposals.","supporting_citations":[],"review_version":1}