## Thursday, April 23, 2015

### Physics teacher takes over the Islamic State

Newsweek, Business Insider, and many other news servers remind us that the boss (and chalif) of ISIS, Abu Bakr al-Baghdadi, was injured in a March airstrike.

Consequently, it was time for the ISIS to pick another chieftain. It turned out to be a former physics teacher from Tal Afar, Iraq named Abu Alaa Afri.

Al-Baghdadi's "main organs" are working – I am not sure whether they include his brain among the "main organs" – but the physics teacher would have many advantages.

We're told that Abu Alaa Afri is
1. the beloved protege of late Osama bin Laden (PBUH: Piss Be Urinating Him)
4. a good public speaker
5. strongly charismatic (see the picture above)
6. the third most important commenter at Peter W*it's crackpot blog
7. an anti-quantum zealot
So things will look rosy for the ISIS – up to the moment when this "cool loop quantum gravity guy" will be bombed away from the Earth, too.

1. I'm very upset of those people, they are making money who should go straigth to your pocket. Sue them! ;-)

2. I'm sure he rejects the many worlds-like ''interpretations'' because he's unable to admit he'd be an anti-quantum zealot in every single universe ;)

3. Now googling "Afri Abu Alaa", that picture from TRF appears.

4. Now googling "Abu Alaa Afri", that picture of TRF is highlighted.

5. I noticed. ;-) I found that picture using the very same Google Search, but before I embedded it, it belonged to a different website. Now it's here. Perhaps it *is* him. It's more likely that it's him than the other pictures - the other pictures are those of al-Baghdadi...

6. True :) still more funny is that Matt Leifer picture wearing the "Anti-Quantum Zealot" T-shirt appears too.

7. That these T-shirts and mugs come from Canada bothers me more than it should. Oh well, at least it will be easier to identify people that don't understand modern physics...

8. Oh man, I need a brain bleach now after exposure to such a powerful charisma...

9. Dear Lubos, I apoligize for wasting your time. I really said stupid things.

I was happy with the fact there is no limit on decoherence. I could make experiments and interpret them using every day language with arbitrary approximation. It is just that I can't do that in the case of de sitter space. That was what I meant by making sense of quantum mechanics. I just have to live with the fact that my experiences are only approximately classical and even in principle can't be arbitrarily classical. The theory just doesn't permit it.

But I think there are other interesting questions. Because of the radiation from the horizon, result of every experiment is always approximate. We may never find what true hamiltonian with arbitrary precision.

But I can I imagine that it may be case that, because of some consistency conditions, space of possible hamiltonians may be discrete and we can find true hamiltonian with finite number of experiments. That would be wonderful.

10. ISIS, the sweet cheeks of political hegemonies! "Lord, make my enemies...ridiculous."

11. The only way to stem the tide of migrants is to end the wars that compel people to flee their homelands: if NATO hadn't of invaded Libya, the country wouldn't be a failed state. PERIOD.

12. Here’s a radical thought: why not back off and allow the various Arab factions to settle their religious/tribal squabbles entirely at their own cost of blood and treasure? It is not in our vital national interest to arbitrarily favor victory of one nest of treacherous vipers over the others.

13. The photos I posted above were taken in 2004, in the splendor of Gaddafi. I'm almost sure that this kind of immigration flows are independent of the regimes of the countries in passing that can oscillate with different degrees of permeability, but never with zero tolerance. In Spain we have a clear example with Morocco, because they can modulate the problem (indeed they do) but not solve it.

14. Looking at what Murder Inc. and their NATO stooges have done to Libya, I can't see why every country that wants to live free doesn't get nuclear weapons.

Nice trick, Luboš. Well done!

Meanwhile, I say a photo-shopped addition could enhance that image's appeal and help to compensate for the enormous offence of having to acknowledge even the mere existence of muslimes anywhere in the world, let alone the particular scum you're talking about.

Stencil in a turbaned tattoo of that illiterate, kiddy-fiddling scraggly beard they call a prophet with his tongue firmly up that mincing creep's arse.

Piss be upon him indeed. And upon them all.

16. Mikel MariñelarenaApr 23, 2015, 7:14:00 PM

Luboš, one of the problems with your proposal is that immigrant flows sometimes reverse. Just to put an example, during the 60, 70s, 80s, Argentina could have laid claim to good parts of the Chilean territory (or the territory of most of its neighbors) on the grounds of migrant flow from that country. However, in the 90s and in this century the Chileans would have gained Argentinian territory on the same grounds. By the same token, in the early-middle 20th century Argentina would have also gained parts of Spain and Italy but these countries would now be regaining their territory and/or gaining additional territory in Argentina. A little bit of a mess.

Another, more important objection, is that there is little reason to expect that re-colonization would not end up like colonization. Bloody insurrections and wars of independence that would consume resources and lives from the colonizers and the colonies. How could one control the subjects unsatisfied by the new arrangement? Who wants to go back to those armed conflicts?

I have a certain hope in genetics. Sooner or later, genetic scientists will discover the specific genes (or gene interactions) that explain the differences that we observe in the average IQ (and some other psychological traits) of different human groups and sub-groups. Once the evidence becomes overwhelming enough, the possibility of new social arrangements to accommodate that evidence may become feasible. Or scientists may even find some "cure" for this problem, who knows.

In the meantime, the world will continue to be a very imperfect place. But let's not forget that it always has been and that we're actually much better off than in the past. Abject poverty is now largely limited to Africa, some Islamic countries and spots of the Caribbean and Central America.

17. I think it's fair, great, and motivating, not a problem, that it would be reversible.

18. These are nothing new. In the 70's many of these "communal" projects existed in the wilderness in the US. My friend stayed there for few month in one of them in New Mexico, got bored out of his skull.

19. Of course, not to mention the semi-failed Kibbutz. Nothing new on the horizon... so I prefer the "imperfect" West, I do not know for sure if it has more future, but certainly it has more present :)

20. I think humans just fantasize about heaven, but actually we prefer dirty action without which it is impossible to live. Last year I stayed at this hotel (in room 12/12 in the pictures)

http://www.fourseasons.com/maldiveslg/

After only few days you want to go back to your daily action. Take Lubos for instance, he lives in a very serene city, yet he gives himself so much headache about problems that does not even affect him like. People will invent actions for themselves if none comes their way.

21. Heven is have the opportunity to go to that hotel, and of course, also, have the certainly to can get back to your humble shelter ;-)

22. Dear Lubos, I have read all of our recent discussion. After reading it again I have one question to ask.

Forget about all things about limit on accuracy on measurement. My statements about it were completely silly, and doesn't really depend on quantum mechanics, they would be silly also in a classical universe.

I saw that, in our discussion, I have said many times that consistent histories make sense and nothing is wrong with it. But copenhagen interpretation requires full decoherence. That is consistent histories gives you copenhagen rules if there is full decoherence. By copenhagen rules I mean the viewpoint in Landau's book. My claim was you can't use copenhagen rules exactly in de sitter space because there is never complete decoherence.

In other situations, you may say that copenhagen rules are exactly true, if you use infinitely big apparatus in measurements. That make sense if there is no limit on size of apparatus.

Of course in every case, world is not short of decoherence, and you can use copenhagen rules practically in all experiments. Inaccuracy due to decoherence will be much smaller than other experimental uncertainties.

I have never said consistent histories require classical mechanics. But copenhagen formalism does, I quoted Landau to show you he also assumed this.

I still don't understand why you disagree with these statements. I would be happy if you explain to me.

You may have a different definition of copenhagen formalism but founders didn't really define everything fully in terms of only quantum properties. I am sure they knew it should be possible but they never said it, at least I don't know.

23. I don't know what to say what hasn't been said millions of times - and is obvious, anyway.

If some interpretation "requires" 100% decoherence or 100% validity of classical physics, well, then it never quite gets what it "requires", so it can't ever be "quite exactly right". It's usually 99.999999999....% right, however.

The infinite big apparatuses are impossible not only in de Sitter space. They are impossible in any practical situation. An apparatus that measures positions "infinitely" accurately is infinitely large and seriously disturbs the original experiment. Infinitely big apparatuses don't exist, anyway.

Outside dS space, one could imagine that there are *some* predictions that could be verified with an ever higher precision. In dS space, whatever the right description is, there is almost certainly a universal limit on precision. But that doesn't mean that *any* laws of QM in dS space are inconsistent or incomplete.

I found my (Slovak) copy of Landau-Lifshitz and the paragraph with the "requiring QM" was scratched by my hand :-), about 20 years ago. It's an unfortunate paragraph. It clearly doesn't affect any calculations anywhere in the book, does it?

24. Darn I wonder if that man is secretly gay.

25. This was one superb (even while not so scientific) post! :-))

26. Although "migrants/refugees" have always existed and I
happen to be one of them, this increasing tide of human suffering is a direct
consequence of warmongers from Washington who, along with their "sub-division"
they control called NATO are directly responsible for chaos, disaster and
atrocities that are taking place in North Africa, Middle East and last but not
least Ukraine as well. Either directly or through their "proxies" they call
allies who do the killing for them - Saudis in Yemen as an example, they are
responsible for what has been going on since 2003 illegal, immoral attack and
invasion of Iraq.

27. Human Rights are doing more damages than any other religions.

28. Dear Lubos, I am sorry that I reply to you five days later, I have been busy.

My point was that copenhagen interpretation is almost completely correct, only its assumption that "measuring devices are essentially classical" was incomplete, like you have said here :

http://motls.blogspot.nl/2011/05/copenhagen-interpretation-of-quantum.html

But, I was thinking that it could be considered to be complete, because there wasn't any obstruction to consider a universe with infinite degrees of freedom. In that case copenhagen rules are completely correct. You don't need to consider CH or anything else.

Of course, in practice you don't have infinite degrees of freedom, but there wasn't any theoretical reason against it.

Anyway, I see CH/DH as only an minor improvement over copenhagen rules and glory of discovery should go to Bohr, Heisenberg, Born etc. . Actually I believe CH/DH is inevitable if you want to apply quantum mechanics to universe or closed systems.

While it is only a minor improvement, I think it is difficult to use CH in practice. This was the reason for my question, since I didn't want to use it but I was uncomfortable with the assumption that measurement devices are classical when you have only finitely many degrees of freedom *even in principle*. And I find it hard to think about in the situations when there isn't any room for (approximately) classical world. Like a universe with 100 degrees of freedom. Universe in de sitter space is qualitatively same with this. Of course, this isn't a problem with quantum mechanics.

I am sorry if I was misunderstood, I didn't wanted to mean that "every quantum theory should give a classical theory in hbar -> 0 limit, and this is required for consistency of quantum mechanics". In fact, I think you can't make a classical theory of spinors, because of rotation by 2*pi ?

I am not sure if there is a problem with infinitely many degrees of freedom in for example ADS/CFT. You can make measurement devices infinitely big with arbitrarily small density and send them infinity. I think ADS/CFT correspondence is supporting this, since there isn't gravity in the other side. Right ?

I think words are important. I started to read volume 3 of Landau, after reading most of volume 1 and volume 2, in high school. I just couldn't get over that paragraph, since it really didn't make sense to me. How a theory could require its limit in its formulation ? Soon, I give up reading it. I had looked into a couple of other books, but they were essentially saying same thing, i.e. they were assuming measurement devices were classical and measure classical properties. I believe that it is backwards. One should explain measurement process just like any other quantum process. Because it isn't taught in this way you see countless wrong remarks on measurement, I assume you have countered much more than me.

29. Dear John, I agree with much (or something) of what you say. CH/DH are a small reformulation of Copenhagen etc.

What I disagree with is your suggestion that the existence of infinitely large apparatuses is a consistency condition for a good and complete theory.

Whether one has apparatuses is just about apparatuses, about a particular state or problem solved by the theory, about one's wealth, it can't be "blamed" on a theory. In a theory, a large apparatus exists in some problems, but it doesn't exist in most other problems. Problems with apparatuses and without apparatuses are *different* problems. It's one of the key points of quantum mechanics that you can't identify these two problems. You can't ignore the apparatus. What the measurement apparatus does to the system *always* matters, according to quantum mechanics. If you can't get this point, then you are still thinking totally classically.

No viable theory allows humans to build infinitely large or infinitely accurate apparatuses. This trivial fact doesn't mean that all theories are incomplete. It's just one of their most trivial predictions.

You're also missing the point when you say that the measurement is "just like any other process". The measurement done by someone else may be studied just like any other process. But the measurement done by the observer himself plays a totally different role. Like crackpots, you again seem to defend some "quantum mechanics without observers" which is really an oxymoron. Physics with non-empty implications but without observers is by definition *classical* physics.

And a theory (e.g. quantum theories in de Sitter space) may imply laws that prevent one from constructing certain machines, i.e. very large or very accurate machines. There is nothing wrong about such predictions.

Of course one can have classical spinor fields. They do change by the sign after you rotate by 2*pi but there is nothing immediately wrong about it. The problem exists but it is much more technical and subtle than you suggest. One fails to get a positive energy and a positive norm when the theory is quantized. That's why one needs the spin-statistics relationship proved by Pauli: integer spin fields are bosonic/commuting, half-integer spins have to be fermionic/anticommuting.

30. Dear Lubos,

This will be last thing I will say on this subject, I promise this time, since I am afraid that you will ban me otherwise :-) . Unless you ask me specifically something, of course.

I am still not sure whether you have understood what I am trying to say.

First thing one should say about quantum mechanics is that, P and/or Q is meaningless unless P and Q commutes. This should be said before anything about probabilities and hilbert space. Operator algebras are more important than anything else.

You have an initial state and you are evolve it with hamiltonian. Then you can ask the question what is the probability that P is true, where P is a projection operator corresponding to a yes/no question. You can do the same thing for histories which satisfy some consistency conditions.

I think what I have written above is completely correct and there is no need to include an observer.

However, we can't do anthing without observations. But to explain observations, we don't need to give observers any special place in the theory.

One can include the observer in the total system (including himself if he wants) and ask the questions what observer/I will observe ? This is totally fine I believe.

Yes, measurements change the system and you can't measure p and q at the same time. But this is a ultimately a consequence of the fact p and q doesn't commute. The fact that measurement apparatus inevitably affect the system it interacts is a "prediction" of consistent histories. You can find it, for example in chapter 17 and 18 of the book Consistent Quantum Theory. It is a very simple calculation, I am sure you can do it in 2 minutes if you still remember the rules. You can prove that if you measure first q then p then q, first and third measurements are totally uncorrelated.

One can talk about closed systems, including universe, without considering outside observers. But one has to careful and use "single framework rule" : You can't combine incompatible histories. (p and q) is the simplest example. This is a precise mathematical statement of the fact that at the very fundamental level realism doesn't exist.

You are right that I want to kill observers. I instrintically think that tip of my finger has well defined position and velocity at the same time. I can see it ! I don't want to build theory on my experiences which is very likely to trick me.

I am almost sure that developer of consistent histories thought like me about observers. If you want I can show you very clear statements by Gell-man and Grifftihs. I think that killing observers was one of the goals they wanted to achieve by developing consistent histories.

But of course Heisenberg was the one who have understood that realism can't be true. I consider him as the most important scientist of the 20th century after Einstein. He would probably think that what I have said above is not science. I disagree, a theory can have non-observable notions.

31. Dear John, this is a long comment. ;-) I think that you know what is the majority I would agree with.

But I have no idea in what sense you have killed observers. The very claim "one has an initial state" means that "an observer has measured some observables whose values determine the initial state". If the observer hasn't measured it, then there is *no* initial state, and all your subsequent discussiion is rubbish.

In the same sense, the observer is critical for the interpretation of any predictions.

Consistent histories make the dependence on the observer manifest. To use this formalism, you first have to use the set of possible mutually exclusive histories. They have to be mutually orthogonal, by the usual condition, so that the probabilistic rules of logic hold. Quantum mechanics then assigns the different alternative histories in the set of alternatives by numerical values of probabilities.

But this choice of the "set of possible alternative histories" isn't determined in any unique way. It may be done more finely and less finely. Even aside from fineness, it may be done in many different way.

Each way to define the perspective - what is the set of histories we want to distinguish - amounts to the choice of an observer.