OverviewFilesCommitsIssuesDocsReleasesPeers

opencog-learn commits / 227bc32

Another push and a wrap it up
227bc32816fa91f0900f95f8ce308a14ced43348
by Linas Vepštas <linasvepstas@gmail.com> · 2026-01-29T01:23:11.000Z

Changed files (1) +367 -7

learn-lang-diary/learn-lang-diary-part-ten-F.lyx +367 -7
……@@ -7514,7 +7514,7 @@ with
75147514\end_inset
75157515
75167516 and Claude claims
7517\begin_inset Formula $\left(\vec{\sigma}\cdot\hat{L}\right)^{2}\chi=-\chi$
7517\begin_inset Formula $\left(\vec{\sigma}\cdot\vec{L}\right)^{2}\chi=-\chi$
75187518\end_inset
75197519
75207520 for the hedgehog.
……@@ -7535,25 +7535,25 @@ grand spin quantum number
75357535\end_inset
75367536
75377537
7538\begin_inset Formula $K=0$
7538\begin_inset Formula $k=0$
75397539\end_inset
75407540
75417541 which is OK if all one wants is the ground state,
75427542 but clearly fails for the vacuum states.
75437543 I didn't catch this early enough,
75447544 so the below proceeds with
7545\begin_inset Formula $K=0$
7545\begin_inset Formula $k=0$
75467546\end_inset
75477547
75487548.
75497549 That's OK,
75507550 for now.
7551
7551 We redo it further below.
75527552\end_layout
75537553
75547554\begin_layout Standard
75557555Assuming Claude is otherwise correct,
7556 the radial equations become
7556 the radial equations (for grand spin zero) become
75577557\begin_inset Formula
75587558\begin{align*}
755975592AEu & =\left(1-r^{2}\right)v^{\prime}-rv\\
……@@ -7567,7 +7567,22 @@ with
75677567\end_inset
75687568
75697569 etc.
7570 Substituting,
7570 XXX When I forced Claude to track grand spin
7571\begin_inset Formula $k\ne0$
7572\end_inset
7573
7574 below,
7575 it begins to appear that the above are not correct.
7576 Maybe.
7577 I am once again running out of steam,
7578 trying to track down the error.
7579 So the derivation below looks pretty but might be wrong.
7580 It clearly needs more serious work.
7581 XXX Caveat Emptor.
7582\end_layout
7583
7584\begin_layout Standard
7585Substituting,
75717586 Claude claims this gives
75727587\begin_inset Formula
75737588\[
……@@ -7684,10 +7699,119 @@ It seems plausible that this might reduce to sphere bessel functions in the
76847699.
76857700 I'm not doing this now;
76867701 first we have to get the
7687\begin_inset Formula $K\ne0$
7702\begin_inset Formula $k\ne0$
7703\end_inset
7704
7705.
7706 XXX Well,
7707 in fact,
7708 the above might be wrong,
7709 because the
7710\begin_inset Formula $k\ne0$
7711\end_inset
7712
7713 efforts below explode into inconsistencies and bad algebra.
7714 So the results above are suspect,
7715 too.
7716 XXX
7717\end_layout
7718
7719\begin_layout Standard
7720Here we go.
7721 I had to force Claude to redo this several times before getting this,
7722 which smells better than the earlier version
7723\begin_inset Formula
7724\[
7725\psi_{+}=u\Phi_{k}^{+}+\tilde{u}\Phi_{k}^{-}\qquad\psi_{-}=iv\Phi_{k}^{-}+i\tilde{v}\Phi_{k}^{+}
7726\]
7727
7728\end_inset
7729
7730for the
7731\begin_inset Formula $\Phi_{k}^{\pm}$
7732\end_inset
7733
7734 the spin–isospin spherical harmonics with Casimir operator angular momentum
7735\begin_inset Formula $K^{2}\Phi_{k}^{\pm}=k\left(k+1\right)\Phi_{k}^{\pm}$
7736\end_inset
7737
7738 .
7739 Then
7740\begin_inset Formula
7741\[
7742\left(\vec{\sigma}\cdot\vec{L}\right)\Phi_{k}^{+}=\lambda\Phi_{k}^{+}
7743\]
7744
7745\end_inset
7746
7747and the anticommutator identity
7748\begin_inset Formula
7749\[
7750\left\{ \left(\vec{\sigma}\cdot\hat{r}\right),\left(\vec{\sigma}\cdot\vec{L}\right)\right\} =-2\left(\vec{\sigma}\cdot\hat{r}\right)
7751\]
7752
7753\end_inset
7754
7755gives
7756\begin_inset Formula
7757\[
7758\left(\vec{\sigma}\cdot\vec{L}\right)\left[\left(\vec{\sigma}\cdot\hat{r}\right)\Phi_{k}^{+}\right]=-\left(\lambda+2\right)\left(\vec{\sigma}\cdot\hat{r}\right)\Phi_{k}^{+}
7759\]
7760
7761\end_inset
7762
7763and we seem to be converging on the idea that
7764\begin_inset Formula
7765\[
7766\Phi_{k}^{-}=\left(\vec{\sigma}\cdot\hat{r}\right)\Phi_{k}^{+}
7767\]
7768
7769\end_inset
7770
7771 which has OK vibes,
7772 for now.
7773\end_layout
7774
7775\begin_layout Standard
7776This means eigenvalues on the lower component are
7777\begin_inset Formula $-\lambda-2$
7778\end_inset
7779
7780.
7781 For the hedge–hog,
7782 we get
7783\begin_inset Formula $\lambda=k$
7784\end_inset
7785
7786 or
7787\begin_inset Formula $\lambda=-\left(k+1\right)$
7788\end_inset
7789
7790 when
7791\begin_inset Formula $k\ne0,$
7792\end_inset
7793
7794 while for
7795\begin_inset Formula $k=0$
7796\end_inset
7797
7798 the special case is
7799\begin_inset Formula $\lambda=-1$
76887800\end_inset
76897801
76907802.
7803 Plugging through,
7804 well,
7805 at this point,
7806 Claude runs into serious trouble.
7807 All sorts of algebra starts fucking up.
7808 It cannot get the
7809\begin_inset Formula $k=0$
7810\end_inset
7811
7812 answer to agree with earlier results.
7813 I've used up all my allotted time on this task,
7814 so must stop.
76917815\end_layout
76927816
76937817\begin_layout Standard
……@@ -7718,6 +7842,242 @@ Robin boundary condition
77187842
77197843.
77207844 Never heard of that but OK.
7845 The coordinate space version with
7846\begin_inset Formula $r$
7847\end_inset
7848
7849 will be simpler to work with.
7850\end_layout
7851
7852\begin_layout Standard
7853Lets pause and take stock.
7854 Lets assume that,
7855 if/when the algebra above is fixed,
7856 we get radial functions
7857\begin_inset Formula $u\sim{}_{2}F_{1}$
7858\end_inset
7859
7860.
7861 These are nice,
7862 and fairly easy to work with and compute numerically;
7863 the boundary condition will be solvable in some milliseconds of CPU time,
7864 so we can do full vacuum sums in dozens of seconds or maybe minutes.
7865 And then what?
7866 We have two parameters to play with.
7867 Naively,
7868 it seems to be three:
7869
7870\begin_inset Formula $\Theta$
7871\end_inset
7872
7873,
7874
7875\begin_inset Formula $R$
7876\end_inset
7877
7878 and
7879\begin_inset Formula $A$
7880\end_inset
7881
7882 but I think we can maybe redo to hold
7883\begin_inset Formula $RA$
7884\end_inset
7885
7886 fixed,
7887 so that it reduces to two paramters.
7888 Or something like that.
7889 In the flat–space case it was only one parameter,
7890
7891\begin_inset Formula $\Theta$
7892\end_inset
7893
7894 because the radial coord was always multiplied by energy.
7895 Here,
7896 we already see that
7897\begin_inset Formula $\epsilon=2AE$
7898\end_inset
7899
7900 and the eigenvalues will be for
7901\begin_inset Formula $\epsilon$
7902\end_inset
7903
7904 so...
7905 whatever.
7906 Its somehow two parameters.
7907\end_layout
7908
7909\begin_layout Paragraph*
7910Why bother?
7911\end_layout
7912
7913\begin_layout Standard
7914So,
7915 now come two fun questions:
7916 Can the energy be made absolutely independent of the bag radius?
7917 I assume the answer will be yes.
7918 Doing so will then fix the curvature as a function of bag radius.
7919 Presumably,
7920 the curvature will got to
7921\begin_inset Formula $\kappa\to-1$
7922\end_inset
7923
7924 as the bag radius goes to a femtometer.
7925 This would be the desired model of confinement and asymptotic freedom.
7926 Next,
7927 what about the chiral condensate?
7928 In flat space,
7929 we had the sigma model
7930\begin_inset Formula $\sigma$
7931\end_inset
7932
7933 being exactly zero inside the bag,
7934 and becoming non–zero only exactly on the boundary.
7935 So,
7936 in flat space,
7937 the bag interior did not look like a sigma model.
7938 This was a big disappointment.
7939 However,
7940 now,
7941 in curved space,
7942 could it be otherwise?
7943\end_layout
7944
7945\begin_layout Standard
7946Why do it this way?
7947 The core problem is that geometry is hard.
7948 If I could do these calculations
7949\begin_inset Quotes eld
7950\end_inset
7951
7952in general
7953\begin_inset Quotes erd
7954\end_inset
7955
7956,
7957 then it seems there is almost surely some Atiyah–Singer magic happening.
7958 But I can't,
7959 and even if I could I might be disappointed.
7960 So,
7961 as a path–finder,
7962 do the calculations assuming sphere symmetry,
7963 and explore this simplified model.
7964 If this simplified model allows the sigma model to emerge from the vacuum,
7965 well then happy day.
7966 If not,
7967 then hopes are dashed.
7968 But it would have gotten much farther than would otherwise have been possible in the
7969\begin_inset Quotes eld
7970\end_inset
7971
7972full general
7973\begin_inset Quotes erd
7974\end_inset
7975
7976 case.
7977\end_layout
7978
7979\begin_layout Standard
7980Suppose the dreams are fulfilled.
7981 Then the breakthrough is that the AdS boundary condition is re–identified with the bag boundary,
7982 instead of being some cosmological thing.
7983 The boundary is also topologically non–trivial,
7984 so the chiral model now lets us ask about harmonic forms on this combined structure.
7985 viz a spin manifold having some kind of dynamics inside the bag,
7986 that spin manifold having some spectrum;
7987 that spectrum,
7988 or rather,
7989 the spectral asymmetry looking like (or I suppose being exactly dual to) a chiral model.
7990 That would be pretty cool and spiffy,
7991 if it were true and could be done.
7992\end_layout
7993
7994\begin_layout Standard
7995But now,
7996 I bop my nose up against some age–old (and old–age) concerns.
7997 The age–old concern is
7998\begin_inset Quotes eld
7999\end_inset
8000
8001what is the most important thing I should work on right now?
8002\begin_inset Quotes erd
8003\end_inset
8004
8005 and the old–age concern is
8006\begin_inset Quotes eld
8007\end_inset
8008
8009shit I'm running out of time,
8010 so I better get the correct answer to the previous question.
8011\begin_inset Quotes erd
8012\end_inset
8013
8014
8015\end_layout
8016
8017\begin_layout Standard
8018The problem with doing geometry is my meta–imagination.
8019 The geometrical,
8020 algebraic universe appears to be constructable by specifying a collection of axioms,
8021 and a collection of inference rules,
8022 and turning the crank,
8023 and discovering gazzillions of identities.
8024 This is how math has always been done,
8025 traditionally:
8026 the more abstract and general and useful identities are given a name,
8027 placing the discoverer into the ranks of history.
8028 While still alive,
8029 mathematicians derive pleasure from finding identities,
8030 stating and proving theorems,
8031 grasping at hypothesis.
8032 The mathematical physics community is less rigorous,
8033 but questions of harmonic forms on Riemann surfaces certainly counts as mathematical physics,
8034 especially when minor modifications give things like Landau superconductivity or Yang–Mills eqns.
8035 So its eminently physics,
8036 in that sense.
8037 And the academic grind–core,
8038 this is what they do:
8039 they have fun cranking on this stuff.
8040 And in the last 2-4 years,
8041 they have been learning how the get LLM's to do some of the more boring parts of the calculations.
8042 Just like I have learned above.
8043\end_layout
8044
8045\begin_layout Standard
8046The personal problem,
8047 for me,
8048 is,
8049 well,
8050 suppose I do discover that some whizzy chiral condensate happens to be equivalent to,
8051 dual to some Riemannian manifold?
8052 That would be pretty cool.
8053 Would it matter?
8054 Well,
8055 I would have had fun,
8056 once again,
8057 in the process,
8058 but I've had lots of fun over my lifetime,
8059 even if the results of most of it have been utterly unimportant in some local scheme of things.
8060 I mean,
8061 how does this work,
8062 anyway?
8063 Steven Weinberg wrote an excellent book on gravitation,
8064 got the Nobel prize in physics for QFT work,
8065 scowled at me when I approached him at a conference,
8066 taught lots of students at UTexas for a good salary,
8067 and then he died.
8068 Whoopla!
8069 Hot patootie,
8070 bless my soul,
8071 I really love that rock–n–roll.
8072\end_layout
8073
8074\begin_layout Standard
8075Anyway,
8076 the upshot is that I can get paid for doing AI research;
8077 I cannot get paid for doing mathematical physics.
8078 This is my current economic environment.
8079 (This section above was written after the section below.
8080 Its placed out of line to conetextualize better with the second attempt to solve the eqns above.)
77218081\end_layout
77228082
77238083\begin_layout Paragraph*