Peter Woit's Blog: Good Stuff, Not Too Hard on String Theory

[marcus]

Today's comment is on the new Michael Douglas paper

the 31 May blog comments on a Michael Douglas paper that
just appeared:


"Statistical analysis of the supersymmetry breaking scale"
Michael R. Douglas (Rutgers/IHES/Caltech)
8 pages
http://arxiv.org/hep-th/0405279

Abstract:
"We discuss the question of what type and scale of supersymmetry breaking might be statistically favored among vacua of string/M theory, building on comments in Denef and Douglas, hep-th/0404116."

http://www.math.columbia.edu/~woit/blog/

 

[marcus]

Peter Woit's 3 June blog comments on the latest Witten paper
(in Nature vol 429, n. 6991, about electroweak symmetry breaking)
Woit supplies a link to Witten's paper and quotes Witten's opinion
concerning the "Anthropic Principle".

unfortunately the link only works for Nature subscribers
so this may mean a trip to the library

(not the paper in question but a related talk by witten at fermilab
in 2003:
http://conferences.fnal.gov/lp2003/program/papers/witten.pdf)



I am curious to know if the recent Nature article shows evidence of a shift in
the focus of Witten's attention. Since Spires database shows
much of the action in HEP
(recent top-cited papers etc) is outside string theory, I would
expect he might be developing other research interests and this paper
might be a straw in the wind. Has anyone looked at it?

 

[jeff]

Peter Woit's 3 June blog comments on the latest Witten paper
(in Nature vol 429, n. 6991, about electroweak symmetry breaking)
Woit supplies a link to Witten's paper and quotes Witten's opinion
concerning the "Anthropic Principle".

unfortunately the link only works for Nature subscribers
so this may mean a trip to the library

I am curious to know if this article shows evidence of a shift in
the focus of Witten's attention.

The way to answer this is to just email witten and ask him.

 

[marcus]

Peter Woit's 4 June blog:
he was visiting the physics department at Dartmouth this week
and gave a colloquium lecture on
"Quantum Field Theory and Representation Theory"

the blog gives a link to the outline and slides

BTW: the QFT/GroupReps lecture has some history too
and includes a funny conversation between Dirac
and an American newspaperman.

 

[selfAdjoint]

That interview between Dirac and a reporter from the Madison, WI Capital Times (I think it was) was terrific, I wish I had a link to the whole thing. At another point the reporter asks if anything worries Dirac about theory, and Dirac says Goedel.

 

[pelastration]

That interview between Dirac and a reporter from the Madison, WI Capital Times (I think it was) was terrific, I wish I had a link to the whole thing. At another point the reporter asks if anything worries Dirac about theory, and Dirac says Goedel.

Maybe this (a part?)? http://faculty.rmwc.edu/tmichalik/dirac.htm

 

[arivero]

It is not vain that Dirac is buried at the foot of Newton (er, and Newton on the right side of God's altar).

 

[selfAdjoint]

Maybe this (a part?)? http://faculty.rmwc.edu/tmichalik/dirac.htm

Oh I see it was the other Madison paper, The State Journal. Well it was a 50% shot. I notice that "Roundy" got more out of the notoriously taciturn Dirac than most physicists ever did. Also notice Roundy's use of Poincare in his guess of what Dirac's initials P.A.M. might be. R was not quite the ignorant hick he pretended to be!

 

[marcus]

I see Urs Schreiber responded today to one of Peter Woit's blogs

also someone called Roland Schwarz who could have the effrontery to be
related to the dreadful Bogdanov brothers.

Now the "comments" thread attached to Woits 5 June blog
has been taken over by Loons
or by one Loon pretending to be several
and it is already over a dozen posts long in a kind of
Loony Satire of scientific discussion.

they are actually a bit funny, or i suspect Peter Woit would
have squelched them

 

[marcus]

Now the "comments" thread attached to Woits 5 June blog
has been taken over by Loons
or by one Loon pretending to be several
and it is already over a dozen posts long in a kind of
Loony Satire of scientific discussion.

there are some remarkable dramatic characters who have appeared
in the comments of Woit's blog
named petitot
moyentot
and grantot

some appear to be French anti-scientific or "post-modern" parodists.
one may be another name for someone called "crankbuster"
I would like to know what some others think of these strange, sometimes quite funny, creatures.

in french letters there has been a cultivation of the art of sacrilege
going back for many centuries and I suppose it is only to be expected

there was that celebrated contemporary of Einstein called
Alfred Jarry of Pataphysics fame
these people do not seem all that different from jarry
but perhaps more well-versed and diabolically clever

http://www.math.columbia.edu/~woit/blog/

PS: BTW Woit blogged today, 10 June. It was about alleged proofs of the Riemann Hypothesis

 

[pelastration]

there are some remarkable dramatic characters who have appeared
in the comments of Woit's blog
named petitot
moyentot
and grantot

some appear to be French anti-scientific or "post-modern" parodists.

Probably it has to do with his June 5 comment "(quote)A couple years ago two French brothers, Igor and Grichka Bogdanov, managed to get Ph.Ds in France and publish several nonsensical papers about quantum gravity in refereed physics journals, several of them rather well-known and prestigious ones. John Baez has a useful web-page about this story.(end of quote).
Internet revenge.

 

[marcus]

Woit blogged again today 12 June
this time about "cosmic strings"

I've taken a look at Sean Carroll's "preposterous universe" blog
which seems highly entertaining especially about GW Bush
has some good cartoons, as well as science news
It looks like one can easily get into the habit of checking
into these mini-amusement-parks and private fun-houses
that people set up, another addictive feature of the internet

 

[selfAdjoint]

The Top Quark Mass

Check out his latest post , about the reanalysis by the Tevatron group of the top quark mass, and the implications this has for the mass of the Higgs particle. Also many of us will want to follow his links, which between them constitute a nice little tutorial on the subject.

 

[marcus]

still more recently a 17 June post about
some expository mathematics by Barry Mazur
and a weekly "Basic Notions" seminar at Harvard which
is partly available online.

Woit also had some words today about a talk by Leonard Susskind
concerning, among other things, "the stupendous Landscape of string theory vacuua"
and a new string theory "rising from the ashes" of the already established string theory

 

[selfAdjoint]

Woit seems to be skeptical about Susskind's papers. Odd.

 

[arivero]

Check out his latest post , about the reanalysis by the Tevatron group of the top quark mass, and the implications this has for the mass of the Higgs particle. Also many of us will want to follow his links, which between them constitute a nice little tutorial on the subject.

The top quark issue is also blogged in
http://golem.ph.utexas.edu/~distler/blog/archives/000380.html#comments
http://blogs.salon.com/0001092/2004/06/09.html#a690
http://preposterousuniverse.blogspot.com/

 

[John]

It's hard to follow all of the new technical terms, like blog, for non-string theory. But there seems to be an attack on string theory, and on funding for powerful accelerators, and on the acquisition of knowledge of the universe in general.

Not being a physics student, I am very good at physics. I started thinking about another model for the universe in about 1985. The strange thing was that all of my ideas seemed to connect with current physics. My ideas got more and more developed; so when the Internet came along, I started to post my ideas, hoping someone would have been lead in the same direction and I could start a discussion: that is, if my ideas were in the direction of right. I hoped my ides would receive some positive response, and we could develop the ideas further, not my ideas, but the right ideas. I kept meeting with a lot of agreement between my ideas and current physics.

Instead, my ideas met with negative attacks.

Here is one of my ideas. I believe protons are hollow spheres made of strings, just the way you would make a hollow sphere out of chicken wire. The “chicken wire” vibrates, and the mass of the vibrating "wire" inflates the proton. When we look at a proton, we only see the one string that is vibrating. We don’t see all the wires that make up the proton. It’s like studying a radio and only seeing the electrical impulses traveling along the wires, without seeing the wires. We would say is a radio is made of tiny electrical impulses, separated by vast distances of nothing. That is absurd, but we would swear that is exactly what the math is telling us, and it would be true.

I am seeing or imagining the wires that make up the proton, and not just the energy that is in the wires.

My latest discovery happened when I learned what a quark is, something every physicist knows, but I didn’t: there are three quarks in a proton. If a proton is a hollow sphere as I say, then each quark is one third of the sphere, so I can know the exact shape of a quark: it's shape is one-third the surface of a sphere. I cut a round orange in three parts and peeled the skin, which gave me one-third the surface of a sphere, so I have my theorized shape of a quark sitting on a table, sticky with orange juice.

What is a string? I say, it is the distance between two separate points. So I take ten quarters that represent points, and arrange them on a table. Start with three quarters to make a triangle, then add a fourth to make a diamond. Then add three more to make a solid hexagon. Add three more, and then you can precisely cover the quarters with the one-third orange peel. The ten quarters and the shape of the orange peel are the same.

Attach three of these quarks made of points together, and you have a hollow sphere. Electrons travel by vibrating one point, then another, then another. They soon vibrate the whole array of points, and you can’t really define where the electron is, except to say it is in the shape that “surrounds” the proton. But that shape is really the proton. The proton is not in the middle, but it IS the shape we call the electron cloud.

The fact ten separate points make the exact shape of one-third the surface of a sphere is an amazing indication my ideas may actually be correct. I say the entire universe is made of individual points of matter, the way a dust cloud is made of individual specks of dust. Light and electrons travel from point to point, which means at the most basic level light can only travel in six directions, and it means there are two forms of dimension. There are spatial dimensions which contain 9 dimensions (plus time) for ten. And there are M-dimensions, which are the energized membranes that make up all the solid objects. It is easy to imagine a picture of that. The dots that make up the picture are arranged sparsely to form space, and they are arranged more densely to form objects.

 

[jeff]

and a new string theory "rising from the ashes" of the already established string theory

The actual quotation due to susskind is:

During the last couple of years an entirely new paradigm has emerged from the ashes of a more traditional view of string theory

I find the difference between this and your quote telling.

 

[marcus]

Peter Woit posted yesterday 1 July
pointing out that Susskind has now withdrawn
his paper about the "stupendous landscape"
and about the new Stringery which he sees "emerging from the ashes"
of yesterday's Stringery

this paper of Susskind, which happly I saved on my desktop
because it was so splendid
provided a window on
the current state of stringy affairs

 

[marcus]

Woit's 1 July blog also talks about the fact
that Mike Douglas paper of 30 May has gone through
several revisions already and is in its 4th version.

We should really try to follow some of this----it seems there is
a lot of vacillation about whether to "predict" (guess?)
the new collider will find evidence of supersymmetry or not,
at the energy level it will be able to acheive

At one time, string theory was supposed to "predict" supersymmetry would be found at that level (and earlier at even lower levels but it wasnt)
but the "predictions" now seem to have evaporated

Is it possible to make the theory predict whatever outcome one guesses is most likely? that would then be a limp and pliable theory. And we would see, as the deadline for prediction approaches, that people's guesswork waffles, and the "predictions" become drained of confidence and start to wobble.

Mike Douglas paper indicates not to expect LHC to see SUSY
and IIRC a recent talk by Witten in Davis carried the same message
and yet only a little while ago there was triumphant confidence---"just wait till LHC comes on line! that will show you skeptics!" It is strange and not a little funny.

 

[Ontoplankton]

Naive question from someone with no technical knowledge of string theory and therefore no opinion on its validity:

Here and elsewhere, I see a lot of people ridiculing the anthropic principle. Can anyone point me to an explanation of the objections to it on the level of rigor of e.g. http://anthropic-principle.com/book?

It just seems like basic common sense to me: if a theory says there are a lot of different worlds, and only some of them contain observers, then we should expect to be in one of those worlds that do contain observers. If we're in a sort of world that is atypical for the set of worlds claimed to exist, but typical for the set of worlds claimed to exist that also happen to contain observers, then this is not evidence against the theory.

I don't understand the people saying "the anthropic principle isn't falsifiable", either. If it's just a decision-theoretical (or confirmation-theoretical, whatever) principle, then why should it be falsifiable?

 

[Ontoplankton]

Mike Douglas paper indicates not to expect LHC to see SUSY
and IIRC a recent talk by Witten in Davis carried the same message
and yet only a little while ago there was triumphant confidence---"just wait till LHC comes on line! that will show you skeptics!" It is strange and not a little funny.

Are you saying this disconfirms string theory in some way? I don't see how. If different people claim the theory predicts different things, then that just means we don't know what the theory predicts yet, and we can maybe find out by thinking harder; it does not mean the theory can say anything we want.

Again, I don't know enough to have any opinion about string theory itself. But if anyone wants a meaningless data point: some of what I do understand of the objections by string theory's detractors looks unfair to me.

 

[selfAdjoint]

Are you saying this disconfirms string theory in some way? I don't see how.

Well if SUSY were to fall, so would superstrings and everything derived from them. You would still have bosonic strings and string field theory.

But it would seem to me that LHC could only falsify low energy SUSY extensions of the standard model. Corrections, anybody?

 

[marcus]

Hi Ontopl. (I guess it means "wandering being" in greek)

I was not sure about your reference to Anthropic principle so i looked back and the nearest post that mentioned it was my post #62.
as you see I was NOT criticizing Anthropic Principle!
quarreling about that principle is a symptom of troubles in string
(I watch but am not part of the quarrel)

the people to look at to see why they reject the Anthropic principle are the string theory insiders like Lubos Motl, David Gross, Edward Witten.

Rejecting the A.P. is part of their resistance to where Susskind has been going and leading a portion of the stringfolk with him.

The A.P. is not an issue for me since i don't find string/M theorizing interesting or relevant to the goal of a background indep. quantum theory of gravity.

I am more interested in theories that preserve the essential features of Gen Rel like background independence, and quantize it in as transparent and straightforward a way as possible.

but when people important in String say something about A.P. I try to keep track.

So my post #62 a ways back in this thread was keeping track of what Witten said about it.

Peter Woit's 3 June blog comments on the latest Witten paper
(in Nature vol 429, n. 6991, about electroweak symmetry breaking)
Woit supplies a link to Witten's paper and quotes Witten's opinion
concerning the "Anthropic Principle".

unfortunately the link only works for Nature subscribers
so this may mean a trip to the library

(not the paper in question but a related talk by witten at fermilab
in 2003:
http://conferences.fnal.gov/lp2003/program/papers/witten.pdf)

...

to get the latest Witten word on A.P. I guess you have to go back to that 3 June post of Peter Woit!

String seems to be in a muddle with some saying "Dont give up! We aren't forced to Anthropologize! Keep working to solve the basic problems!"

but on the other hand some like Susskind saying that the huge number of possible basic states (string vacua)----the "stupendous landscape" he has called it, of an estimated 10-to-the-100 power of distinct possible models of nature all with a potential for predicting distinct things about nature----can only be resolved by appealing to the A.P.

As you can imagine, I rather avoid arguing about the A.P.
My personal suspicion is that it is wishful thinking for String theorists to imagine that it could help them out of the
String theory crisis. Susskind looks to me like he is clutching at straws.

In the end a successful physical theory that pretends to improve on the Standard Model plus incorporate gravity has to explain certain numbers (numbers that the Standard Model explains, the cosmological constant, etc.)

Historical example: when Feynman and Schwinger made QED the theory explained certain numbers, like the magnetic moment of the electron. (it did not thow up its hands in a vague appeal to the fact that we have a life-friendly universe)
this is what physical theories are supposed to do: explain why the magnetic moment of the electron is such-and-such.
That was the 1950s.
So? It is different now?

so I am sympathetic to what I think is an honorable courageous stand by string theorists who want their theory to have explanatory power.
they aren't ready to lower their expectations.
I can understand how a self-respecting string theorist might deplore the anthropic tendencies of his colleagues

but intellectually I do not take a position on it.

I do not anticipate much from string theory whichever way they go, whether they accept A.P. and try to get some benefit or whether they reject it. so I do not have an opinion about A.P.----it is just not an issue.

 

[Haelfix]

Well if SUSY were to fall, so would superstrings and everything derived from them. You would still have bosonic strings and string field theory.

But it would seem to me that LHC could only falsify low energy SUSY extensions of the standard model. Corrections, anybody?

Thats right, but much of the theoretical prejudice to like SUSY in the first place starts vanishing really fast as you push it to higher and higher energy. In fact, things get downright ugly (at the level of minimal SUSY), as you start having to do really nasty finetuning to make things work... Which defeats the original purpose. We might additionally have to rethink GUT theory...

Not to mention, there are atmospheric tests that will need an explanation.

Several other things will happen. Wimp based models based on the hope that SUSY will save them, will run into a dead end. At which point, we'll be stuck with some very unnappealing alternatives.

Imo it would be one of the bigger crisis's physics has undergone in recent history.. Larger even then the measurement of the Lamb shift.

 

[marcus]

... some of what I do understand of the objections by string theory's detractors looks unfair to me.

You may be mistaking being skeptical of string hype as being a "detractor".
I don't favor this school of quantum gravity or that. If string theory ever managed to predict a number, and they could put the theory on the line for real testing, I would be happy either way it came out.
It would be great to get some progress in quantum gravity.
But all I hear on that score is excuses and wishful thinking.

String theory has been way over-hyped and IMO has made limited progress since say 2001, while some of the alternative approaches have gotten little attention but have made considerable advances. (that would be an interesting thread topic! new QG results, progress since 2001)

I am not partisan to one alternative or the other, if Loop gravity fails and Simplex gravity succeeds, or viceversa, that is fine with me either way. Or if spin foam succeeds and the others fail.
If String would make a surprise comeback and turn out to be genuine theoretical physics (intead of an Elegant Mathematical Contruct) that would be wonderful too!

I try to report what is happening: the battle royal inside String, the decline in String papers, the decline in String citations, the progress in other lines of Quantum Gravity research, like Simplex, Foam, and Loops. (and Hawking seems to think also in Path Integral--his own non-string approach to quantum gravity).

Dont confuse reporting with detracting. If the muddle changes, and the string people get their act together, I will be delighted to report that. I find the main effort required is to cut through the hype Stringsters constantly put out: the lengthy litany of reasons why the newer alternatives have to fail, the "theoretical" reasoning is offered to prove that only string can succeed. They treat as sacred cow what is looking suspiciously like another failed attempt.

 

[marcus]

Some recemt Not Even Wrong blogs and comments

Peter Woit has been busy and some interesting comments have been
coming in from Thomas Larsson, Urs Schreiber, Arivero and others

Smolin on the Anthropic Principle
http://www.math.columbia.edu/~woit/blog/archives/000059.html

Polyakov: String Theory Is Crazy
http://www.math.columbia.edu/~woit/blog/archives/000058.html

Hawking in Dublin
http://www.math.columbia.edu/~woit/blog/archives/000057.html


some other memorable N.E.W. blogs

http://www.math.columbia.edu/~woit/blog/archives/000039.html

http://www.math.columbia.edu/~woit/blog/archives/000032.html

http://www.math.columbia.edu/~woit/blog/archives/000031.html

http://www.math.columbia.edu/~woit/blog/archives/000028.html

http://www.math.columbia.edu/~woit/blog/archives/000027.html


anyone who doesn't check Woit's blog regularly is missing a treat

 

[jeff]

You may be mistaking being skeptical of string hype as being a "detractor".
I don't favor this school of quantum gravity or that. If string theory ever managed to predict a number, and they could put the theory on the line for real testing, I would be happy either way it came out.
It would be great to get some progress in quantum gravity.
But all I hear on that score is excuses and wishful thinking.

String theory has been way over-hyped and IMO has made limited progress since say 2001, while some of the alternative approaches have gotten little attention but have made considerable advances. (that would be an interesting thread topic! new QG results, progress since 2001)

I am not partisan to one alternative or the other, if Loop gravity fails and Simplex gravity succeeds, or viceversa, that is fine with me either way. Or if spin foam succeeds and the others fail.
If String would make a surprise comeback and turn out to be genuine theoretical physics (intead of an Elegant Mathematical Contruct) that would be wonderful too!

I try to report what is happening: the battle royal inside String, the decline in String papers, the decline in String citations, the progress in other lines of Quantum Gravity research, like Simplex, Foam, and Loops. (and Hawking seems to think also in Path Integral--his own non-string approach to quantum gravity).

Dont confuse reporting with detracting. If the muddle changes, and the string people get their act together, I will be delighted to report that. I find the main effort required is to cut through the hype Stringsters constantly put out: the lengthy litany of reasons why the newer alternatives have to fail, the "theoretical" reasoning is offered to prove that only string can succeed. They treat as sacred cow what is looking suspiciously like another failed attempt.

I don't favor this school of quantum gravity or that. If lqg ever managed to predict a number, and they could put the theory on the line for real testing, I would be happy either way it came out.
It would be great to get some progress in quantum gravity.
But all I hear on that score is excuses and wishful thinking.

lqg has been way over-hyped and IMO has made limited progress since say 2001, while some of the alternative approaches have gotten little attention but have made considerable advances. (that would be an interesting thread topic! new QG results, progress since 2001)

I am not partisan to one alternative or the other, if strings fail and some other theory succeeds, or viceversa, that is fine with me either way. Or if strings succeeds and the others fail.
If lqg would make a surprise comeback and turn out to be genuine theoretical physics (intead of an Elegant Mathematical Contruct) that would be wonderful too!

I try to report what is happening: the dissolution of lqg, the decline in lqg papers, the decline in lqg citations, the progress in other lines of Quantum Gravity research, like strings.

Dont confuse reporting with detracting. If the muddle changes, and the lqg people get their act together, I will be delighted to report that. I find the main effort required is to cut through the hype lqger’s constantly put out: the lengthy litany of reasons why the newer alternatives have to fail, the "theoretical" reasoning is offered to prove that only LQG or some theory other than strings. They treat as sacred cow what is looking suspiciously like another failed attempt.

All joking aside though, the difference between strings and the other approaches is that the difficulties in the latter are actually fatal.

 

[arivero]

All joking aside though, the difference between strings and the other approaches is that the difficulties in the latter are actually fatal.

Is there a non-go theorem, thus?

 

[selfAdjoint]

A good discussion starting over at ]Not Even Wrong[/URL] on whether the quantisation prescription in LQG is really pukka. Smolin started off with an email to Woit making the same claims for LQG that he does in the paper we've been reading. Then Urs Schreiber weighs in making the same claim that LQG quantisation is deficient, or at least not standard, that he made in the aftermath to Thiemann's string quantisation paper.

Basically his point is that "canonical quantisation" means you transform the p and q variables which span the phase space, into operators, and in the Ashtekar new variables approach to LQG one of the corresponding variables, the "magnetic" form, cannot be elevated to an operator because it becomes ill-defined. So the LQG people simply replace it with an operator that seems to them what the magnetic form could have become if it woulda transformed meaningfully. Or so Urs says, reading their papers. I have not confirmed this for myself and I am eager to see what Smolin replies.

Then Urs says this procedure is itself ill-defined because there are many possible choices for the "reasonable" operator. Or at least you have to prove that there aren't, which the LQG folks haven't done. Urs' point then is that this vitiates Smolin's repreated assertion that the the quantisation and uniquesness theorems are rigorous.

It would be really nice if somebody with real chops from the Ashtekar school, like Thiemann or Sahlmann, could get into this discussion. But we take what we can get. Urs is also pursuing some related topics at the String Coffee Table.