The double-slit experiment is often framed as evidence that microscopic objects are “both waves and particles,” or that a wavefunction “collapses” upon measurement. This paper gives a QMU-native, apparatus-centric explanation in the Aether Physics Model (APM) by separating the experiment into three operational layers: (1) Transport layer (space): Light is treated as a conserved transport content, denoted here as $\mathrm{ligt}$, distributed over expanding photon fronts. The measurable quantity in space is the delivered areal density (intensity) $\mathrm{lint}(\nu;\mathbf{r})$. Interference is asserted at this transport layer: two outgoing channels can superpose and form stable bright and dark regions in $\mathrm{lint}$ at the screen plane before any detection event occurs. (2) Boundary layer (aperture): The slit-mask is modeled as a transfer operator $T$ acting on the incident delivery density:\[\mathrm{lint}_{\mathrm{out}}(\nu;\mathbf{r}) = T\,\mathrm{lint}_{\mathrm{in}}(\nu;\mathbf{r}).\]For a double slit, the outgoing density is produced by two transfer channels, $T_1$ and $T_2$, whose superposition yields an intensity-level interference form\[\mathrm{lint}_{\mathrm{tot}}(P)=\mathrm{lint}_1(P)+\mathrm{lint}_2(P)+2\sqrt{\mathrm{lint}_1(P)\mathrm{lint}_2(P)}\cos\Delta\phi(P).\]The phase difference is written in QMU-normalized form using the chronovibration identity and the dimensionless cadence:\[c = F_q \lambda_C,\qquad \nu^*=\frac{\nu}{F_q},\qquad \lambda=\frac{\lambda_C}{\nu^*},\]so that\[\Delta\phi(P)=2\pi\frac{\Delta \ell(P)}{\lambda}=2\pi\,\nu^*\,\frac{\Delta \ell(P)}{\lambda_C}.\]In the far-field approximation with slit separation $d$, screen distance $L$, and transverse coordinate $x$, $\Delta\ell(x)\approx d x/L$, giving\[\Delta\phi(x)\approx 2\pi\,\nu^*\,\frac{d}{L}\,\frac{x}{\lambda_C}.\]This emphasizes that the fringe map is a geometric count in units of $\lambda_C$ scaled by the dimensionless cadence $\nu^*$. (3) Detection layer (matter): Detection is a discrete resonance gate event in matter, not a continuous “field readout.” The receiver is represented by a binary acceptance function\[G(\nu^*,\text{alignment})\in\{0,1\},\]and the event-rate density follows the gated effective drive\[\mathrm{lint}_{\mathrm{eff}}(\mathbf{r})=\int G(\nu^*,\text{alignment})\,R(\nu^*)\,\mathrm{lint}(\nu;\mathbf{r})\,d\nu,\qquad\dot N_e(\mathbf{r})\propto \mathrm{lint}_{\mathrm{eff}}(\mathbf{r}).\]Single-particle hits therefore build the fringe pattern because discrete events sample a pre-existing transport interference pattern in $\mathrm{lint}$. Coherence window and a falsifiable fringe condition The paper introduces a receiver coherence window $\tau_g$ and its QMU-normalized form $\tau_g^* = F_q\tau_g$. This produces a detector gate coherence length\[L_g = c\,\tau_g = \lambda_C\,\tau_g^*,\]and a direct, falsifiable interference condition\[\Delta \ell(P)\lesssim \lambda_C\,\tau_g^*.\]A key operational refinement is the \emph{minimum law} for the observed visibility rolloff length:\[L_{\mathrm{rolloff}} \approx \min(L_c,\,L_g),\]where $L_c$ is a transport coherence length set by source bandwidth / wavefront quality, and $L_g$ is the detector’s gate coherence length. This predicts two distinct regimes and a detector-dependent saturation plateau when $L_c$ is increased beyond $L_g$. Which-path marking as controlled timing-jitter injection Which-path devices are treated as measurable degradations (timing/phase jitter, alignment scrambling, or mode partitioning), not metaphysical collapse. A minimal quantitative model treats marking as injecting an RMS delay $\sigma_t$ between channels, with QMU-normalized jitter $\sigma_t^* = F_q\sigma_t$. For Gaussian jitter, the visibility obeys\[V = V_0 \exp\!\left[-2\pi^2(\nu^*)^2(\sigma_t^*)^2\right],\]yielding a clean functional form for tunable weak-to-strong marking protocols. Slit-edge participation and QMU surface knobs (including qsfo) To make boundary participation experimentally reportable, the slit transfer operator is decomposed as\[T = T_{\mathrm{geom}} + T_{\mathrm{surf}},\]where $T_{\mathrm{surf}}$ captures mask material / coating / roughness / polarization-sensitive surface channels. The paper introduces QMU-native surface oscillation knobs:\[\mathrm{qsfo} := \frac{c^3}{\lambda_C} = {\lambda_C}^2 {F_q}^3,\qquad \mathrm{qsfi}:=\frac{\lambda_C}{c^3}=\frac{1}{\mathrm{qsfo}},\]and defines a dimensionless surface-participation ratio\[\Pi_{\mathrm{surf}} := \Omega_{\mathrm{surf}}\;\mathrm{qsfi},\]so that “edge effects” are reported as measured QMU parameters rather than qualitative caveats. What this upload contains This Zenodo upload includes the full paper (PDF) written in the QADI template style, with: (i) a transport/boundary/detection decomposition, (ii) QMU-normalized fringe geometry, (iii) a detector-dependent coherence-window prediction ($\tau_g^*$ and $L_g$), (iv) the minimum-law saturation test, (v) a timing-jitter which-path reduction law, and (vi) QMU surface-mode reporting via $\mathrm{qsfo}$/$\mathrm{qsfi}$. The appendix provides SI bridges and explicitly states that numerical anchors are reported using the MKS (SI) version of the QMU conversion tables. Suggested citation Thomson III, D. W. The Double-Slit Experiment in the Aether Physics Model (APM): Transfer Operators, Gate Coherence, and QMU Predictions. DOI: 10.5281/zenodo.18446424 Zenodo (Version 1.0).