Let q=(x,z) and fix A≥20, 0<ε≤10−3. Use a smooth monotone step with all endpoint derivatives zero. On the first interval [0,ε] interpolate from
Hb=HA(x)+Ho(z)
to
Hq=−Δq+41qTKqq,Kq=(13/8−5/8−5/813/8).
Keep Hq until 2π−ε, then interpolate to Ha=Ho(x)+HA(z) on the final interval. The ramp intervals are contained in the duration 2π. They are not appended to the commensurate time.
The two normal frequencies of Hq are 1 and 3/2. Consequently its unmodified duration-2π wave operator is −iSWAPxz. The smooth gate just defined is a different propagator; no exact factor scratch reset will be inferred from that observation. Its true entrance is RA(x)φ(z) and its record must match the actual entry sign of x. This is a path statement requiring a complete-current estimate.
using the same ramps and middle Hq. Let ψs be the exact Gaussian evolution of φ(x−sA)φ(z), and set
χ=2(1+e−A2/2)ψ++ψ−.(6.1)
Both common and relative phases are retained in these exact quadratic evolutions. The comparison is not a population mixture. It need not stay normalized, but ∥χ∥≤2.
Lemma 6.1 (Finite-ramp Gaussian tube)
The position centers are ±M(τ) and the common position covariance and centered velocity matrix are Σ,B. On the gate,
with x,z exchanged at the entrance. Every ordered word of degree at most two in x,z,Px,Pz, applied to χ, has norm at most G=100(A+2)2.
Proof
For the unswitched sensor the center is
Mq=2A(cosτ+cos(3τ/2),cosτ−cos(3τ/2)).
Writing v=cos2(τ/2) gives 2∣Mq/A∣2=16v3−20v2+5v+1. Its minimum is 83/108−510/27>9/50, so ∣Mq∣>.3A and ∣Mq′∣≤13/8A<4A/3. The sensor fundamental matrix in (q,P) has norm at most 3/2. The difference generator is at most 5/4 and is supported for total length 2ε. Volterra's equation therefore gives
∥F−Fq∥≤23(e15ε/4−1),∥F∥≤23e15ε/4.
The opposite affine forces contribute at most 3εe15ε/4A to the phase-space center difference. Their sum with the preceding homogeneous error is less than .009A, by ea≤(1−a)−1. This proves the center bounds and 1.35/.29<5 proves the normal bound.
The exact sensor position covariance has eigenvalues 1 and cos2(3τ/2)+(4/9)sin2(3τ/2). Its centered velocity norm is at most 5/8. The fundamental-matrix bounds imply ∥FFT−FqFqT∥<.02. Block inversion in B=ΓPqΣ−1 gives
∥B∥<85+501(25+854925)<1.
On the ramps Fq is within (27/8)ε of the identity or endpoint swap, whence ∥F−Iendpoint∥<.01 and the Wigner covariance error is less than .021. Together with the center error these imply (6.3); orthogonal harmonic phase-space evolution preserves these bounds during the matched hold. Lastly the means are bounded by 1.6A and phase-space variances by 3. Gaussian fourth moments, plus the commutator correction [qi,Pj]=2iδij, bound degree-two ordered words; coherent summation costs at most 2. The stated 100(A+2)2 bounds each of these terms.
Every ordered position/momentum word of degree at most two on these errors is bounded by 15hg on the gate and 15(hg+tBA) on the two-coordinate hold.
Proof
The nonlinear well differs from its s-centered harmonic comparison by
and the shifted potential is at most 20(A+1)2(1+∣ξ∣)2. Since 1+∣r∣≤2(A+1)(1+∣ξ∣), the identity K(Dsψs)=DsKψs−2Ds′∂rψs−Ds′′ψs gives the explicit envelope
∣K(Dsψs)∣≤5400(A+1)7(1+∣ξ∣)3w(r)∣ψs∣.(6.7)
Indeed the three terms have coefficients at most 4800,400,200, respectively. Here w=e−A2/2 on the own collar and 1 outside.
We include the Gaussian integration which supplies the exponential in (6.4). The density is dominated by 11/9 times the isotropic two-dimensional normal density of variance 11/10. Outside the collar, the normal centered coordinate is below −.7A. Set a=.7A/11/10>1. Repeated integration by parts gives
∫a∞u6γ(u)du=(a5+5a3+15a)γ(a)+15Φ(−a).
Using Φ(−a)≤γ(a)/a and (1+∣ξ∣)6≤35(1+∣ξ1∣6+∣ξ2∣6), its outside weighted square-root moment is at most
92(A+1)3e−A2/10.
For explicit constants, the squared polynomial prefactor is bounded by (11/9)24370(2/5)<8400<922, while a2/4=49A2/440>A2/10. On the whole Gaussian, E(1+∣ξ∣)6≤32[1+48(11/10)3]<2100<462. The inside contribution is therefore at most 46e−A2/2. Since 5400(46+92)<106, (6.7) gives ∥K(Dsψs)∥≤106(A+1)10e−A2/10. Coherent summation yields BA. This forcing is present only on the two ramps during the gate, and throughout the nonlinear hold.
Next write W=V+c. Direct use of the expression for UA gives
W≥∣q∣2/8+λ,∥ΔW∥∞≤M:=A4+23A2+2.
For compact smooth vectors,
∥Kf∥2=∥Δf∥2+∥Wf∥2+2∫W∣∇f∣2−∫ΔW∣f∣2.(6.8)
Positivity gives ∥f∥≤∥Kf∥/λ, and hence ∥Wf∥,∥Δf∥≤1+M/λ2∥Kf∥. For A≥20, M/λ≤2/7. The switching multiplier satisfies
∣Dsw∣≤3∣q∣2/8+7A2/4+1/2≤3W,
so ∥Dswf∥≤4∥Kf∥. The equation for KE consequently costs at most 4∣η′∣∥KE∥+∥KR∥, where η is the ramp weight and R is the complete coherent forcing. The total variation of the two ramps is 2. Gronwall gives (6.5); the static hold has no time-graph cost and gives (6.6).
For completeness, the entrance graph bound is a wave estimate. On r≥0, put a=φ(r−A), b=φ(r+A), t=b/a=e−Ar and h(t)=1+t−1+t2. Then 0≤h≤t, ∣h′∣,∣h′′∣≤1. The differences between (a+b)/2 and RA and their first two derivatives are bounded respectively by b/2 times
1,r/2+3A/2,r2/4+3Ar/2+13A2/4+1/2.
Reflect on the negative half-line. For k≥0,
∫∣r∣kmin{γ(r−A),γ(r+A)}dr≤k!e−A2/2,
because e−Ar≤e−r for A≥1 and 2/2π<1. The normalization correction is bounded by 1−(1+e−A2/2)−1/2≤e−A2/2/2. Gaussian moments and reordering Pr=rP−2i now bound every degree-two entrance error word by 400(A+1)2e−A2/4. The elementary quadratic bound on UA and the shift c then give the larger, convenient ∥K(0)E(0)∥≤h0.
Finally (6.8) bounds each degree-two word: position squares use ∥∣q∣2f∥≤8∥Wf∥; momentum products use Fourier ∥∂i∂jf∥≤∥Δf∥; mixed words use its positive weighted-gradient term. Reordering adds at most 2∥f∥, and lower words follow by interpolation. All are below 15∥Kf∥ with the displayed M/λ2 bound. These are derivative and moment estimates, not consequences of wave norm alone.
Proposition 6.3 (A different receiver records the entry sign)
Under the gate above, the actual probability that z fails to finish in the region assigned to the entry sign of x is at most CFcopy. The two regions are z≤−A/2 and z≥A/2. The statement holds for arbitrary correlations in the original actual law subject to (5.2).
Proof
Use the plane n(τ)⋅q=0, where n=M/∣M∣. It starts at x=0. A path changing its side must cross that spacetime surface. The relative current is j⋅n+ρn′⋅q on the plane. Expand the current of the full coherent sum before taking its absolute value. The diagonal branch terms are bounded by ∣ψs∣2(3A+6∣q∣); the two interference terms and moving-plane cross-density term together are bounded by ∣ψ+ψ−∣(12A+18∣q∣). These follow from the Gaussian amplitude gradients −Σ−1(q−sM)/2, phase velocities sM′+B(q−sM), and (6.2).
Each branch's plane density is at most (2/3)e−A2/27, since .292/(2⋅1.1)>1/27 and (2π⋅.4)−1/2<2/3. The conditional tangential mean has magnitude below A and variance at most 1.1, so its conditional E∣q∣ is at most A+2. Use ∣ψ+ψ−∣≤(∣ψ+∣2+∣ψ−∣2)/2 and the denominator in (6.1). The full plane flux is at most 30(A+1)e−A2/27 per unit time. Integration over 2π<7 is bounded by Fcg. No Gaussian branch has been sampled as the actual state.
The trace inequality for Hilbert-valued functions,
∥f∣n⋅q=0∥2≤2∥f∥∥∂nf∥,
applied also to ∂nf and the tangential position times f, gives trace bounds 2Kg,3Kg,3Kg for the error and 2G,3G,3G for the comparison. Expanding the current difference gives at most 24KgG+12Kg2 per unit time. Expanding the moving-surface density difference gives at most 60KgG+30Kg2, since ∣n′∣<5. Integrating both over 2π<7 gives Feg. These bounds explicitly retain the cross terms and the quadratic error current.
At the endpoint the plane need not be exactly z=0. The strict tube gives ∣mx/mz∣≤1/19. On ∣z∣≥A/2, ∣x∣≤A, the signs of n⋅q and z agree. The complement under the coherent comparison is bounded by Bend. Indeed the receiver mean is at least .45A from its nearer middle boundary and the scratch mean at least .95A from its outer boundary. The variance is at most 1.1; one-dimensional Mills bounds and ∣χ∣2≤∣ψ+∣2+∣ψ−∣2 give the two displayed 2/A terms with exponents 2A2/25 and 2A2/5. The true density adds at most 2∥χ∥∥E∥+∥E∥2≤Eend.
For the reference flow, spacetime coarea bounds the expected crossing count by the integrated absolute relative current. The prescribed scalar potentials are smooth in position, have at most quadratic growth, and have polynomially bounded spatial derivatives. Common oscillator domains and weighted differentiation propagate every finite Schwartz order of this entrance over the finite schedule. In the full configuration, normalization and Cauchy–Schwarz give
For a baker stage with complete bounded drift V, the last two bounds acquire respectively ∥V∥∞ and 2∥V∥∞∥∇Ψ∥2; its action also stays finite. The value on nodes is defined by the zero-current convention. Finite weighted graph propagation makes these quantities integrable on the finite schedule. The complete spacetime current (ρ,j) is C1, is conserved, and has unit mass at every time. In particular
∫0Tf∫ρ>0∂τρ+ρj⋅∇ρdqdτ<∞,∫0Tf∫∣j∣dqdτ<∞.
The first follows by summing the displayed time-density and logarithmic current bounds; the second controls escape to infinity. There is no physical boundary or singular excluded set in this effective configuration space. These are the hypotheses of the general current criterion in [6, Theorem 1], which supplies almost-everywhere global flow and equivariance on the finite schedule. Thus coarea applies, including possible nodes through their reference-null path exclusion. The original cap (5.2) transfers the union of the crossing and endpoint events to the actual law, with the single factor C. Selecting a sign and then reapplying a conditional cap is unnecessary.