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opencog-learn commits / d5a43c4

More. Seems we have the ground state now.
d5a43c4b207ddd3795354197424b7e74c391278c
by Linas Vepštas <linasvepstas@gmail.com> · 2026-01-28T23:39:50.000Z

Changed files (1) +124 -4

learn-lang-diary/learn-lang-diary-part-ten-F.lyx +124 -4
……@@ -6851,7 +6851,7 @@ Metric
68516851
68526852\begin_layout Standard
68536853Poincare ball metric with curvature
6854\begin_inset Formula $K=-1/A^{2}$
6854\begin_inset Formula $\kappa=-1/A^{2}$
68556855\end_inset
68566856
68576857,
……@@ -7466,12 +7466,12 @@ and the flat–space version would have been
74667466\end_inset
74677467
74687468To regain flat space
7469\begin_inset Formula $K=0$
7469\begin_inset Formula $\kappa=0$
74707470\end_inset
74717471
74727472 in the limit,
74737473 set
7474\begin_inset Formula $K\to0$
7474\begin_inset Formula $\kappa\to0$
74757475\end_inset
74767476
74777477 which means
……@@ -7523,7 +7523,36 @@ with
75237523 maybe,
75247524 I guess.
75257525 Who knows.
7526 Assuming it is,
7526 Well,
7527 not entirely;
7528 in fact,
7529 Claude assumed that the
7530\begin_inset Quotes eld
7531\end_inset
7532
7533grand spin quantum number
7534\begin_inset Quotes erd
7535\end_inset
7536
7537
7538\begin_inset Formula $K=0$
7539\end_inset
7540
7541 which is OK if all one wants is the ground state,
7542 but clearly fails for the vacuum states.
7543 I didn't catch this early enough,
7544 so the below proceeds with
7545\begin_inset Formula $K=0$
7546\end_inset
7547
7548.
7549 That's OK,
7550 for now.
7551
7552\end_layout
7553
7554\begin_layout Standard
7555Assuming Claude is otherwise correct,
75277556 the radial equations become
75287557\begin_inset Formula
75297558\begin{align*}
……@@ -7596,10 +7625,101 @@ Pöschl-Teller potential
75967625\end_inset
75977626
75987627.
7628 Never heard of that before.
75997629 So it knows about this.
76007630 Someone must have figured this out.
76017631\end_layout
76027632
7633\begin_layout Standard
7634Next,
7635 we can solve the above.
7636 Clause guesses that its hypergeometric,
7637 and arrives at the exact solution
7638\begin_inset Formula
7639\[
7640u=\frac{\sqrt{\xi^{2}-1}}{\xi}\;{}_{2}F_{1}\left(a,b;2;1-\xi^{2}\right)
7641\]
7642
7643\end_inset
7644
7645with
7646\begin_inset Formula $\xi=\cosh\rho$
7647\end_inset
7648
7649 and
7650\begin_inset Formula $a=\left(3+\sqrt{1+4\epsilon^{2}}\right)/4$
7651\end_inset
7652
7653 and
7654\begin_inset Formula $b=\left(3-\sqrt{1+4\epsilon^{2}}\right)/4$
7655\end_inset
7656
7657 OK,
7658 that's trctable.
7659 In chart coords its
7660\begin_inset Formula
7661\[
7662u=r\;{}_{2}F_{1}\left(a,b;2;-\frac{r^{2}}{1-r^{2}}\right)
7663\]
7664
7665\end_inset
7666
7667It seems plausible that this might reduce to sphere bessel functions in the
7668\begin_inset Formula $A\to\infty$
7669\end_inset
7670
7671 flat space limit.
7672 It should reduce to
7673\begin_inset Formula $j_{0}$
7674\end_inset
7675
7676 with
7677\begin_inset Formula $v$
7678\end_inset
7679
7680 going over to
7681\begin_inset Formula $j_{1}$
7682\end_inset
7683
7684.
7685 I'm not doing this now;
7686 first we have to get the
7687\begin_inset Formula $K\ne0$
7688\end_inset
7689
7690.
7691\end_layout
7692
7693\begin_layout Standard
7694Lets pause to look at the boundary conditions.
7695 Claude claims that
7696\begin_inset Formula
7697\[
7698\left.\frac{v}{u}\right|_{r=R}=-\tan\frac{\Theta}{2}
7699\]
7700
7701\end_inset
7702
7703which cranked through is supposed to be
7704\begin_inset Formula
7705\[
7706u^{\prime}\sin\frac{\Theta}{2}=\left(\epsilon\cos\frac{\Theta}{2}-\frac{2+\tanh^{2}\rho_{R}}{\tanh\rho_{R}}\sin\frac{\Theta}{2}\right)u
7707\]
7708
7709\end_inset
7710
7711which Claude claims is a
7712\begin_inset Quotes erd
7713\end_inset
7714
7715Robin boundary condition
7716\begin_inset Quotes erd
7717\end_inset
7718
7719.
7720 Never heard of that but OK.
7721\end_layout
7722
76037723\begin_layout Paragraph*
76047724Punt
76057725\end_layout