How does the asymmetric envelope \(g(u)\) modify the transition elements in the algebraic structure, and how does the choice of inner product affect the results — while distinguishing the symmetry proof from the numerical computation?
Change of variable \(u=2\pi/x\); derivation of the envelope \(g(u)\); construction of the algebraic identity \(H_g(gY)=-gY''\); proof that the symmetry of \(D(u)\) forces \(\mathcal{A}_{13}^{(0)}=0\) in the reference model; computation of \(\mathcal{A}_{13}\) and \(\mathcal{A}_{12}\) at \(x_p=21\) (ratio \(R_{13/12}\approx0.60352\)); sensitivity of \(x_p\); comparison of inner-product effects.
Exact differential identity on the interior domain where \(g>0\) is smooth and \(p\) is defined. Exact symmetry argument in the reference model. Numerical computations via scipy.integrate.quad with documented tolerance and reproducible code. Definition of the appropriate Hilbert space (due to \(1/g^2\) singularities at the endpoints) remains an open question.
Introduce the change of variable \(u = 2\pi/x\), so that the function becomes:
where the envelope is:
If we define \(p(u) = g'(u)/g(u)\), the explicit formula is:
The following operator satisfies the algebraic identity:
and satisfies: \(H_g(gY) = g(-Y'')\). This means that if \(-Y_n'' = \lambda_n Y_n\), then \(H_g(gY_n) = \lambda_n(gY_n)\).
In physics, "selection rules" forbid certain transitions due to symmetry under reflection. In our domain \(u \in (0, 2\pi)\), the reflection is \(\hat{P}u = 2\pi - u\).
Under reflection about the midpoint of the domain, \(\hat{P}u = 2\pi - u\), the transition operator \(D(u) = \cos(u/2)\) transforms to \(-D(u)\). Combined with the parity of the base states, \(Y_n(2\pi-u) = (-1)^{n+1}Y_n(u)\), this symmetry forces the reference element \(\mathcal{A}_{13}^{(0)}\) to vanish in the base model.
But the envelope \(g(u)\) is not symmetric under this reflection:
Introducing the asymmetric envelope removes the symmetry argument that forced \(\mathcal{A}_{13}^{(0)} = 0\) in the reference model. That alone is not sufficient to guarantee that the integral is nonzero, but the numerical computation under the current definitions gives \(\mathcal{A}_{13} \neq 0\) at \(x_p=21\).
We choose the transition operator \(D(u) = \cos(u/2)\). For full documentation and reproducibility, we define the base states \(Y_n(u)\) and the normalized states \(\Psi_n(u)\) using the unweighted measure (\(du\)) as follows:
The matrix elements and their ratio are then defined by:
To study the dependence of the ratio on the parameter \(x_p\), it was computed at several values. The results show a smooth variation over the tested range, with no special behavior visible at \(x_p=21\).
| \(x_p\) | \(R_{13/12}\) | Note |
|---|---|---|
| 10 | 0.61417 | Smooth variation |
| 15 | 0.60742 | Smooth variation |
| 21 | 0.60352 | Reference value |
| 30 | 0.60056 | Smooth variation |
| 50 | 0.59778 | Smooth variation |
quad are practical numerical estimates, not rigorous guaranteed error bounds.
import numpy as np
from scipy.integrate import quad
def g(u, xp=21.0):
if u <= 0 or u >= 2*np.pi: return 0.0
return ((u / (2*np.pi))**5) * np.log(2*np.pi / u) * np.exp(-2*np.pi / (xp * u))
def Y(n, u): return np.sin(n * u / 2.0)
def D(u): return np.cos(u / 2.0)
def norm_integrand(u, n, xp): return (g(u, xp) * Y(n, u))**2
def matrix_element_integrand(u, m, n, xp, N_m, N_n):
psi_m = g(u, xp) * Y(m, u) / np.sqrt(N_m)
psi_n = g(u, xp) * Y(n, u) / np.sqrt(N_n)
return psi_m * D(u) * psi_n
def calculate_ratio(xp):
print(f"--- Computation at x_p = {xp} ---")
N_1, err_N1 = quad(norm_integrand, 0, 2*np.pi, args=(1, xp), limit=200)
N_2, err_N2 = quad(norm_integrand, 0, 2*np.pi, args=(2, xp), limit=200)
N_3, err_N3 = quad(norm_integrand, 0, 2*np.pi, args=(3, xp), limit=200)
print(f"N_1 = {N_1:.10f} (err: {err_N1:.1e})")
print(f"N_2 = {N_2:.10f} (err: {err_N2:.1e})")
print(f"N_3 = {N_3:.10f} (err: {err_N3:.1e})")
A_12, err_A12 = quad(matrix_element_integrand, 0, 2*np.pi, args=(1, 2, xp, N_1, N_2), limit=200)
A_13, err_A13 = quad(matrix_element_integrand, 0, 2*np.pi, args=(1, 3, xp, N_1, N_3), limit=200)
print(f"A_12 = {A_12:.8f} (err: {err_A12:.1e})")
print(f"A_13 = {A_13:.8f} (err: {err_A13:.1e})")
R = (abs(A_13)**2) / (abs(A_12)**2)
print(f"R_13/12 = {R:.8f}\n")
return R
x_values = [10, 15, 21, 30, 50]
for xp in x_values:
calculate_ratio(xp)
--- Computation at x_p = 10 --- N_1 = 0.0030709680 (err: 2.1e-14) N_2 = 0.0048258897 (err: 2.0e-14) N_3 = 0.0042376174 (err: 2.0e-14) A_12 = 0.62678855 (err: 1.2e-14) A_13 = -0.49120653 (err: 1.1e-14) R_13/12 = 0.61416656 --- Computation at x_p = 15 --- N_1 = 0.0033843304 (err: 2.1e-14) N_2 = 0.0052677281 (err: 2.0e-14) N_3 = 0.0046153844 (err: 2.0e-14) A_12 = 0.62379990 (err: 1.2e-14) A_13 = -0.48617326 (err: 1.1e-14) R_13/12 = 0.60742342 --- Computation at x_p = 21 --- N_1 = 0.0035779945 (err: 2.1e-14) N_2 = 0.0055384080 (err: 2.0e-14) N_3 = 0.0048466511 (err: 2.0e-14) A_12 = 0.62207485 (err: 1.2e-14) A_13 = -0.48326669 (err: 1.1e-14) R_13/12 = 0.60351552 --- Computation at x_p = 30 --- N_1 = 0.0037307068 (err: 2.1e-14) N_2 = 0.0057506430 (err: 2.0e-14) N_3 = 0.0050279116 (err: 2.0e-14) A_12 = 0.62077276 (err: 1.2e-14) A_13 = -0.48107216 (err: 1.1e-14) R_13/12 = 0.60055827 --- Computation at x_p = 50 --- N_1 = 0.0038792969 (err: 2.1e-14) N_2 = 0.0059561711 (err: 2.0e-14) N_3 = 0.0052033919 (err: 2.0e-14) A_12 = 0.61955102 (err: 1.2e-14) A_13 = -0.47901258 (err: 1.1e-14) R_13/12 = 0.59777767
The current model establishes an algebraic transformation of \(Z(u)\), identifies the symmetry responsible for the vanishing of the reference matrix element, and shows how the asymmetric envelope modifies the transition elements under the chosen normalization.
At \(x_p = 21\), the numerical integration gives \(R_{13/12} \approx 0.60352\). The dependence of this ratio on \(x_p\) has been examined, and reproducible computations are provided.
These results motivate further research into the associated spectral problem, the appropriate state space and inner product, and the model's possible significance in physical systems.