Chapter 58
de Broglie Wavelength and Momentum Feedback
Quantum Coherence and Boundary Systems
Author: Mark Anthony Higgins
© Mark Anthony Higgins 11 October 2025
Revised Date: 23 February 2026
flow "de Broglie Wavelength and Momentum Feedback" v1.0
# ---------- PURPOSE ----------
# Encodes the de Broglie relation λ = h/p and the feedback that boundaries impose on phase.
# Boundaries (ring/box/slit) enforce phase continuity, quantising k and p via curvature feedback.
# IB measures phase coherence; IB < 1 introduces fringe loss / imperfect quantisation.
# ---------- PARAMETERS ----------
params:
units: "SI"
h: real = 6.62607015e-34 # Planck constant [J·s]
ħ: real = 1.054571817e-34 # reduced Planck [J·s]
m: positive # particle mass [kg]
v: real? # particle speed [m/s] (nonrelativistic regime)
p: real? # momentum [kg·m/s] (if not given, p = m v)
E: real? # total energy [J] (if not given, E = p^2/2m)
L: positive? # characteristic length (ring circumference or box length) [m]
boundary: enum("free","ring","box","slit") = "free"
n: integer? # mode index for quantisation (n = 0,±1,±2,… for ring; n = 1,2,… for box)
IB: 0.0..1.0 = 1.0 # coherence index (fringe/phase integrity)
aperture: positive? # slit width for diffraction [m]
dt: positive? # timestep [s]
λ_leak: nonnegative = 0.0 # coherence leak rate [s^-1]
# ---------- STATE ----------
state Wave:
λ: real # de Broglie wavelength [m]
k: real # wave-number [1/m]
ω: real # angular frequency [rad/s]
vp: real # phase velocity [m/s]
vg: real # group velocity [m/s]
quant_error: real # mismatch to boundary condition
phase_integral: real # ∮ p·dl (Bohr–Sommerfeld) [J·s]
allowed_k: real? # nearest quantised k
fringe_visibility: real # interference contrast ~ IB
regime: str # "free","quantised","diffracting","decohering"
# ---------- INVARIANTS ----------
invariants:
# Momentum / energy closure (nonrelativistic by default)
if params.p is undefined and params.v is defined:
params.p = params.m * params.v
if params.E is undefined and params.p is defined:
params.E = params.p^2 / (2*params.m)
# de Broglie relations
Wave.λ = params.h / (params.p or 1e-99)
Wave.k = 2π / Wave.λ # also k = p/ħ
Wave.ω = (params.E or 0) / params.ħ # E = ħω
# Velocities (nonrelativistic)
Wave.vg = params.p / params.m # group velocity
Wave.vp = (params.E or 0) / (params.p or 1e-99) # phase velocity
# Boundary feedback → quantisation (choose rule by boundary)
if params.boundary == "ring" and params.L is defined:
# periodicity: k_n = 2π n / L
Wave.allowed_k = 2π * (params.n or round(Wave.k * params.L / (2π))) / params.L
Wave.quant_error = abs(Wave.k - Wave.allowed_k)
Wave.phase_integral = (params.p or 0) * (params.L) # ≈ n h target
elif params.boundary == "box" and params.L is defined:
# hard walls: k_n = nπ / L, λ_n = 2L/n
Wave.allowed_k = (π * (params.n or round(Wave.k * params.L / π))) / params.L
Wave.quant_error = abs(Wave.k - Wave.allowed_k)
Wave.phase_integral = 2 * (params.p or 0) * (params.L) # round-trip action ~ n h
elif params.boundary == "slit" and params.aperture is defined:
# diffraction scale (first minimum): sin θ ≈ λ/aperture
Wave.quant_error = 0
Wave.phase_integral = 0
else:
Wave.quant_error = 0
Wave.phase_integral = 0
# Coherence → visibility
Wave.fringe_visibility = params.IB
# Coherence decay (optional)
if params.λ_leak > 0 and params.dt is defined:
params.IB = clamp(params.IB - params.λ_leak * (1 - params.IB) * params.dt, 0, 1)
Wave.fringe_visibility = params.IB
# Regime tag
if params.boundary in ["ring","box"] and params.L is defined:
Wave.regime = "quantised"
elif params.boundary == "slit" and params.aperture is defined:
Wave.regime = "diffracting"
elif params.IB < 1:
Wave.regime = "decohering"
else:
Wave.regime = "free"
# ---------- TRANSFORMS ----------
transforms:
set_velocity:
comment: "Update p via p = m v (nonrelativistic)."
params.v += Δv
params.p = params.m * params.v
# refresh λ,k via invariants
enforce_boundary_feedback:
comment: "Snap k to nearest allowed mode to satisfy phase continuity."
if Wave.allowed_k is defined:
Wave.k = Wave.allowed_k
params.p = params.ħ * Wave.k
Wave.λ = 2π / Wave.k
params.E = params.p^2 / (2*params.m)
Wave.quant_error = 0
open_slit:
comment: "Switch to diffracting regime with a given aperture."
params.boundary = "slit"
params.aperture = new_aperture
decay_coherence:
comment: "Reduce IB (fringe visibility) via leakage."
params.IB = clamp(params.IB - 0.01 * (1 - params.IB), 0, 1)
Wave.fringe_visibility = params.IB
restore_coherence:
comment: "Small feedback restoration of coherence."
params.IB = clamp(params.IB + 0.01 * (1 - params.IB), 0, 1)
Wave.fringe_visibility = params.IB
# ---------- MONITORS ----------
monitors:
de_broglie_consistency:
assert abs(Wave.k - (params.p or 0)/params.ħ) <= 1e-9 or params.p is undefined
comment: "k = p/ħ and λ = h/p consistent."
boundary_condition:
if params.boundary in ["ring","box"] and params.L is defined:
assert Wave.quant_error <= 1e-9
comment: "Phase continuity satisfied (quantised mode)."
coherence_bounds:
assert 0 <= params.IB <= 1
# ---------- SCENES ----------
scenes:
free_particle:
given params:
m: 9.11e-31
v: 1.0e5
boundary: "free"
IB: 1.0
expect:
Wave.regime = "free"
comment: "Unbounded motion — λ = h/p sets phase scale; no quantisation."
ring_quantisation:
given params:
m: 9.11e-31
v: 2.0e5
L: 1.0e-6
boundary: "ring"
IB: 1.0
enable:
- enforce_boundary_feedback
expect:
Wave.regime = "quantised"
Wave.quant_error = 0
comment: "Periodic boundary enforces k_n = 2π n / L → p_n = ħ k_n."
box_modes:
given params:
m: 9.11e-31
v: 1.0e5
L: 5.0e-9
boundary: "box"
n: 3
IB: 1.0
enable:
- enforce_boundary_feedback
expect:
Wave.regime = "quantised"
comment: "Hard-wall box: k_n = nπ/L, λ_n = 2L/n; momentum locked to mode."
single_slit_diffraction:
given params:
m: 9.11e-31
v: 5.0e4
boundary: "slit"
aperture: 100e-9
IB: 0.9
expect:
Wave.regime = "diffracting"
Wave.fringe_visibility ≈ 0.9
comment: "Angular spread set by λ/aperture; IB controls fringe contrast."
decohering_beam:
given params:
m: 9.11e-31
v: 8.0e4
boundary: "free"
IB: 0.7
λ_leak: 0.02
dt: 1.0
enable:
- decay_coherence
expect:
Wave.regime = "decohering"
Wave.fringe_visibility ↓
comment: "Environmental coupling reduces IB — momentum spread broadens."
# ---------- NOTES ----------
notes:
- **de Broglie:**
\[
\lambda = \frac{h}{p},\qquad k = \frac{2\pi}{\lambda} = \frac{p}{\hbar},\qquad
E = \frac{p^2}{2m},\quad \omega = \frac{E}{\hbar}.
\]
- **Velocities (nonrelativistic):**
\[
v_g = \frac{d\omega}{dk} = \frac{p}{m},\qquad
v_p = \frac{\omega}{k} = \frac{E}{p} = \frac{p}{2m}.
\]
- **Boundary Quantisation:**
Ring: \(k_n = 2\pi n/L\) (periodic).
Box: \(k_n = n\pi/L,\ \lambda_n = 2L/n\) (nodes at walls).
Bohr–Sommerfeld (heuristic): \(\oint p\,dl = n h\).
- **Diffraction Scale:** First minimum \(\sin\theta \approx \lambda / a\) for slit width \(a\).
- **Coherence Law:**
\[
\dot{I_B} = -\lambda_{\text{leak}}(1 - I_B)
\]
controls fringe visibility / mode purity.
- **Interpretation (HST–Flow):** Boundaries act as **phase feedback loops**: they accept only those \(k\) that close the loop coherently.
High \(I_B\) → sharp modes / fringes; low \(I_B\) → broadened momentum distribution and washed patterns.
When matter moves, it does not carry a wave; it is the wave — a self-referential curvature loop whose wavelength arises from the feedback between motion and phase continuity.
The de Broglie relation,
\[ \lambda = \frac{h}{p} \]
is therefore not a conversion between momentum and wavelength, but a boundary feedback law: the geometry that phase must adopt for coherence to remain closed through motion.
Every boundary — whether a ring, box, or slit — enforces this closure by allowing only those curvatures whose phases fit seamlessly upon returning.
Momentum becomes quantised because the boundary demands self-agreement of phase.
Classically, a particle of momentum is associated with a wavelength
\[ \lambda = p\,h \]
When this wave is confined by a boundary of length , coherence can survive only if an integer number of wavelengths fits within that boundary:
\[ n\lambda = 2L \;(\text{box}), \qquad n\lambda = L \;(\text{ring}) \]
Hence,
\[ p_n = n\frac{h}{2L} \quad \text{or} \quad \frac{n h}{L} \]
Quantisation arises not from discrete energy “packets” but from the phase-closure requirement imposed by the geometry that contains the wave.
In the HST framework, the de Broglie wavelength measures the curvature feedback length — the spatial period required for a particle’s internal phase to re-align with its boundary conditions.
Each full loop of curvature corresponds to one phase rotation of .
The feedback condition,
\[ \oint p\,dl = n h \]
ensures that curvature memory remains coherent over the full loop.
A change in momentum changes the loop’s curvature and therefore its wavelength — a reciprocal relationship ensuring that the total phase across one cycle remains .
The boundary thus acts as a coherence mirror: momentum determines wavelength, wavelength determines how phase closes, and closure defines which momenta are permitted.
A wave traversing a ring or box continually reflects or wraps around, comparing its current phase with its origin.
Any mismatch produces interference — constructive for closed phases, destructive for non-integer multiples.
The only stable solutions are those where curvature realigns perfectly, satisfying
\[ k_n = \frac{2\pi n}{L}\;(\text{ring}), \qquad k_n = \frac{n\pi}{L}\;(\text{box}) \]
These discrete values represent standing curvature patterns — phase-locked feedback loops.
Momentum quantisation is therefore boundary-enforced coherence: each allowed state is a mode of stable recursion.
When a wave passes through an open boundary (slit or aperture), feedback becomes partial.
The boundary no longer enforces strict phase closure, so curvature spills outward, producing a diffraction pattern.
The angular spread obeys:
\[ \sin\theta \approx \frac{\lambda}{a} \]
where is the slit width.
Here, the coherence index quantifies how well phase remains aligned:
As falls, the momentum distribution broadens — a signature of open-boundary feedback.
The persistence of wave coherence follows the same universal law:
\[ \dot{I_B} = -\lambda_{\text{leak}} (1 - I_B) \]
Boundaries with high reflectivity () maintain standing waves indefinitely;
open apertures () allow phase information to leak away.
The de Broglie wave therefore evolves according to the degree of feedback closure imposed by its environment.
From the HST–Flow perspective, the de Broglie relation is the local expression of global coherence.
Momentum and wavelength are not separate variables but conjugate manifestations of curvature feedback.
Every quantised state is therefore a stable recursion of curvature memory, sustained by the dialogue between motion and boundary.
The de Broglie wavelength describes how motion encodes coherence through curvature.
Momentum defines curvature density; boundaries feed that curvature back upon itself.
Quantisation is the condition of perfect feedback; diffraction is the partial opening of the loop.
In the HST–Flow view:
Thus, every particle is not a point but a loop of recursive motion,
and every wavelength is the distance over which that loop remembers itself.
Motion becomes geometry when its phase returns to meet itself.