Gross Calls String Theory A Bizarre Science That Is A Dangerous Business

[marcus]

...it seems to me that most of the recently published papers on string theory have NOT much to do with the landscape...

Again, I am not sure that you are right, but I would be very glad if you ARE right and if this represents a significant trend.

this is actually a very important issue which you have raised, Demy. The Anthropic Landscape tendency is almost certainly the worst aspect in String ideology. It would be wonderful news if it were on the decline!

Perhaps we could try to find out, or gauge this in some way. I would propose to look at the lineup of the invited plenary speakers at the most recent Strings conference and see what proportion of them are Landscapists.

We could also recall the video of David Gross' talk at the end of Strings 07 which gave a summary of the conference and his view of the present state of the field. He touched on this issue.

Here are some of the Strings 07 invited plenary talks. Slides and video are online here:
http://gesalerico.ft.uam.es/strings07/040_scientific07_contents/041_speakers.htm
We could sample their slides and see. I hope you are right.

M. Becker [Texas A&M] SLIDES - VIDEO - VIDEO - DOWNLOAD
Runaway in the Landscape

R. Bousso [Berkeley] SLIDES - VIDEO - VIDEO - DOWNLOAD
Cosmological Predictions in the Landscape

M. Douglas [Rutgers & IHES, Paris] SLIDES - VIDEO - VIDEO - DOWNLOAD
Exploring the Kähler potential

D. Gross [KITP, Santa Barbara] SLIDES - VIDEO - VIDEO - DOWNLOAD
Perspectives

S. Kachru [Stanford] SLIDES - VIDEO - VIDEO - DOWNLOAD
Comments on Anti-branes

R. Kallosh [Stanford] SLIDES - VIDEO - VIDEO - DOWNLOAD
Testing String Theory with CMB

A. Linde [Stanford] SLIDES - VIDEO - VIDEO - DOWNLOAD
Eternal Inflation and String Theory Landscape

 

[Demystifier]

Just as an example, today there are 13 new papers at arXiv:hep-th. Among them, only 5 are directly related to string theory. Among these 5 string papers, 2 of them are directly related to the landscape, while other 3 are not. Try to do a similar analysis with any other day in recent past, I strongly believe that you will obtain similar results.

 

[marcus]

Just as an example, today there are 13 new papers at arXiv:hep-th. Among them, only 5 are directly related to string theory. Among these 5 string papers, 2 of them are directly related to the landscape, while other 3 are not. Try to do a similar analysis with any other day in recent past, I strongly believe that you will obtain similar results.

Good! So we have a number 40 percent. If you are right, and the Landscapist fad is on the way out, then this number should decline. I hope it does! We can watch a bit and see.

I like this approach. It has an element of objectivity.

 

[Chronos]

The landscape debacle is truly unfortunate. The premise that string is sufficient to allow for a TOE is undeniable. Contending it permits the existence of our universe is reasonable. Insisting it predicts everything because all other possible universes are equally probable is . . . insulting.

 

[Demystifier]

The landscape debacle is truly unfortunate. The premise that string is sufficient to allow for a TOE is undeniable. Contending it permits the existence of our universe is reasonable. Insisting it predicts everything because all other possible universes are equally probable is . . . insulting.

As I already said once, asking string theory to explain the Standard Model of "elementary" particles is like asking quantum electrodynamics to explain life on Earth.

 

[arivero]

As I already said once, asking string theory to explain the Standard Model of "elementary" particles is like asking quantum electrodynamics to explain life on Earth.

Are you intending to be ironic or is it a defense of the anthropic principle?

Let me do my try:

"asking Planck scale string theory to explain the Standard Model of "elementary" particles is like asking QCD scale string theory to explain gravity".

 

[Demystifier]

Are you intending to be ironic or is it a defense of the anthropic principle?

It is a sort of the defense of the anthropic principle. More precisely, it is an argument that it is quite natural that a fundamental theory contains a huge number of different solutions, so that it cannot really explain why we live in a very specific solution in which we live. A "theory of really everything" should be also a theory of the initial conditions, which string theory is certainly not supposed to be.

 

[arivero]

A "theory of really everything" should be also a theory of the initial conditions, which string theory is certainly not supposed to be.

Indeed it seems that the label "Theory Of Everything" implies, to laymen, more than the strict goals of understanding the Standard Model and -perhaps- gravity. The old label "Grand Unified Theories" was perhaps more concrete: we are interested on the "guts" of the animal, no more.

 

[wolram]

I am sure there must be some value in all this across the garden fence chit chat, or you very cleaver guys would not be indulging in it but , does it solve anything?

Addition

I can remember when we had engineering meetings to resolve a problem, they proved quite useless, it was found that a single observation, of one guy solved the problem.

 

[Sauron]

Exactly! And it is to David Gross' credit that he is one of the few (sometimes it seems the only) prominent figure within the string club who is willing to speak out publically against the direction taken by Susskind and many others.

Well, Lubos Motl and Jackes Distler are totally agianst landscape and they publish routinatelly in their journals about it. I guess they are, at least, relativelly prominent figures. There is also something called "Swampland", a program initiated by horava (or another well known figure in strng theory, I have no time now to verify it) which is something like a program against landscape consisting in the search for selfconsistency of low energy effective field theories with the full strig theory. This puts more realisitic limits amount the really obtenaible vacua.

The two more recent books on string theory, Michel dine "Supersimmetryand string theory" and Becker, Becker, Schwartz: "string theory and M-theory" have an introduction to the landscape but they are very coutous about it´s actual convenience. I wouldn´t say that the string landscape could be considered a signature of the viewpoints of most people working in string theory (fourtunatelly).

 

[ccdantas]

It is a sort of the defense of the anthropic principle. More precisely, it is an argument that it is quite natural that a fundamental theory contains a huge number of different solutions, so that it cannot really explain why we live in a very specific solution in which we live. A "theory of really everything" should be also a theory of the initial conditions, which string theory is certainly not supposed to be.

A theory of everything is not expected to be a theory of contingency (I do not see a meaning for the latter, btw). There are many solutions (different orbit configurations) for the gravitational problem. The fact that, e.g., Mars currently has a given orbit does not depend on any intrinsic necessity, it is purely contingent. But the fact that its orbit fits an ellipse indicates the acceptability of Newtonian gravitational theory as a correct description of the physical phenomenon involved (under the domain of validity of the theory). What is the theory that "shapes" the masses of particles?

 

[turbo]

A theory of everything is not expected to be a theory of contingency (I do not see a meaning for the latter, btw). There are many solutions (different orbit configurations) for the gravitational problem. The fact that, e.g., Mars currently has a given orbit does not depend on any intrinsic necessity, it is purely contingent. But the fact that its orbit fits an ellipse indicates the acceptability of Newtonian gravitational theory as a correct description of the physical phenomenon involved (under the domain of validity of the theory). What is the theory that "shapes" the masses of particles?

Quite a penetrating observation, Christine - not that I'd expect less of you. The fact that an ad hoc modification of Newtonian gravitation (MOND) has predictive power that correctly described the gravitational behavior of low-surface-brightness galaxies a decade before their observation illustrates that theory can be made to conform to observation. In no way does it address the foundational physics, though, so though that modification appears to work in galactic domains, we still don't know why. At least MOND works for a broad range of spiral galaxies, and that range of applicability (generalization) is promising, though I expect that the modification addresses some foundational physics that is as-yet not understood.

Somehow, I'm always drawn to the LQG side of the force (cheesy Star Wars reference) because there are hints (including recent MAGIC observations of possible energy-dependent variable c) that the LQG folks are on a productive path, especially in regard to describing some fundamental quality(ies) of space. In comparison, String appears allegorical and hard to pin down. I know it is popular and well-funded, but the engineer in me wants mechanics based on observables.

 

[arivero]

What is the theory that "shapes" the masses of particles?

The point is that the masses of the particles are known to be suspiciously regular, with exactitudes beyond the law of low numbers or the birthday paradox. So it is hoped that there is some theory shaping the masses.

String theory aimed to this niche two times: first at QCD energies, and then going up to Planck but claiming contact with GUT theories and renormalization group running from high to low energy. And due to he closeness between Planck scale and GUT scale, for sure every theory of quantum gravity tries to claim some possibility to fix the masses. I think it is a bad idea; in the low energy regime almost everything points to the electroweak scale, the only two exceptions being 1) The GUT running of coupling constants and 2) the neutrino seesaw scale.

 

[Fra]

What is the theory that "shapes" the masses of particles?

So, let's say we looking for a theory. Then one can ask what is the method that shapes our theories? Then we are apparently looking for a theory of the evolving theories, aren't we?

Or is everyone satisfied with the ad hoc method, combined with the falsification selection method?

Opinions?

/Fredrik