Joe Lykken's List of Stringy Goods and Bads

[marcus]

http://www-conf.slac.stanford.edu/ssi/2005/lec_notes/Lykken1/default.htm

Every year Stanford SLAC has a summer institute. This summer Fermilab Joe Lykken is giving a series of talks called "String Theory for physicists". His first 7 slides summarize what he thinks are the stringy goods and bads.

In case anyone might want to discuss, question them, clarify, I will transcribe the list. The slides are handwritten--so in case the list is interesting to anyone here at PF, it may be useful to have it copied out. The rest of this post is a transcription of Lykken's list: "good/bad news about string theory"

====

Good: String theory is a consistent theory of quantum gravity.

Bad: It's really a generator of an infinite number of mostly disconnected theories of quantum gravity, each around a different ground state. No background independent truly off-shell formulation of string theory is known (yet).

====

Good: String theory is unique. i.e. there is only one distinct consistent theory of "fundamental" strings

Bad: It has an infinite number of continuously connected ground states plus a google of discrete ones. There appears to be no vacuum selection principle, other than the stability of supersymmetric vacua, which gives the wrong answer.

====

Good: String theory gives you chiral gauge theories, with big gauge groups, for free + complicated flavor structure at low energies is mapped into the geometry of extra dimensions

Bad: Doesn't like to give the Standard Model as the low energy theory.
A "typical" string compactification is either much simpler (with more SUSY and bigger gauge groups) or much more complicated (lots of extra exotic matter extra U(1) gauge groups etc)

====

Good: String theory predicts supersymmetry and extra dimensions of space

Bad: It's happy to hide them both up at the Planck scale

====

Good: No length or energy scales are put in by hand; all scales should be determined dynamically

Bad: Appears to be too many (hundreds!) scalar fields (moduli) with too much SUSY to get determined dynamically; may be forced to appeal to cosmic initial conditions (the Landscape)

====

Good: String theory gives a microphysical description of (at least some) black holes, resolves their singularities

Bad: Doesn't seem to resolve the singularity of the Big Bang
(good for inflation, though)

====

Good: Lots of powerful dualities
including weak <--> strong coupling dualities
and short <--> long distance dualities

Bad: Can't tell what are the "fundamental" degrees of freedom.
String theory not necessarily a theory of strings

====

Good: Unification of all the forces is almost for free, may need
an (interesting) extra dimensional assist

Bad: In our most realistic string constructions so far, SU(3)_C,
SU(2)_W, and U(1)_Y have essentially nothing to do with each other: related to different features of complicated D-brane setups

====

Good: AdS/CFT duality shows that 10 dim. String theory in a certain background is equivalent to a 4 dim. gauge theory!
Use this e.g. to show that RHIC QCD physics maps onto quantum gravity/black holes.

Bad: Add more confusion: can't tell an extra dimension apart from technicolor

====

Good: We are starting to use string theory to learn tricks for perturbative QCD, understanding the QCD strings, etc.

Bad: The QCD community was already doing fine, thank you.

 

[marcus]

RR "Railroad" Tucci has created a little song about the current status of String research. This curious message appeared four days ago at Woit's blog. It could be a good balancer for Lykken's list
---------------------------------------------------------

YA GOT TROUBLE

Well, you got trouble, my friend.
Right here, I say trouble right here in Jersey City
Why, sure, I’m a stringy player
Certainly mighty proud to say,
I’m always mighty proud to say it
I consider the hours I spend pulling out all my hair are golden
Help you cultivate horse sense and a cool head and a keen eye

Now, folks, let me show you what I mean
You’ve got one, two, infinitely many stringy vaccua
Vaccua that mark the difference between a gentleman and a bum
With a capital ‘B’ and that rhymes with ‘Stree’ and that stands for ‘String’

And all week long, your Jersey City youth’ll be fritterin’ away
I say, your young men’ll be fritterin’
Fritterin’ away their noontime, suppertime, choretime, too

Ya got trouble, folks, right here in Jersey City
with a capital ‘T’ and that rhymes with ‘Stree’
and that stands for ‘String’

May I have your attention, please? Attention, please
I can deal with this trouble, friends,
with the wave of my hand, this very hand
Please observe me, if you will I’m Professor Harold Hill
and I’m here to organize a quantum computer band

Oh think, my friends, how can any stringy guess
ever hope to compete with a gold Q comp
Rah, rah, rah-da-da-da-da, rah-rah
Remember, my friends, what a handful of Apple players
did to the famous, fabled walls of I B M
Oh, corporation walls come a-tumblin’ down

Oh, a band’ll do it, my friends, oh yes
I said a Q C band, do you hear me?
I say Jersey City’s got to have a Q C band
and I mean she needs it today
Well, Professor Harold Hill’s on hand
and Jersey City’s going to have her Q C band
Just as sure as the Lord made little green apples
and that band’s going to be in uniform.


posted by R.R. Tucci, August 2nd, 2005
http://www.math.columbia.edu/~woit/wordpress/?p=230#comments

 

[ohwilleke]

IIRC the Music Man's band was less than met the eye, but perhaps that is the point.

 

[marcus]

IIRC the Music Man's band was less than met the eye, but perhaps that is the point.

ohwilleke, my problem here is total ignorance, which puts me at a considerable disadvantage. I tremble to confess that I have never heard of the Music Man's band. So are these lines of RR Tucci a parody of some wellknown pop lyrics?

(that sounds like a naive question)

================

[EDIT] So it was a Broadway show! and later a movie.
I looked in google for "Music Man" and found this
http://www.imdb.com/title/tt0056262/#comment

thanks for the lead.
so that is who Professor Harold Hill is---the assumed name of a con-artist musical instrument salesman

 

[Locrian]

Hah, what a great list of Goods & Bads.

 

[ohwilleke]

ohwilleke, my problem here is total ignorance, which puts me at a considerable disadvantage. I tremble to confess that I have never heard of the Music Man's band. So are these lines of RR Tucci a parody of some wellknown pop lyrics?

(that sounds like a naive question)

================

[EDIT] So it was a Broadway show! and later a movie.
I looked in google for "Music Man" and found this
http://www.imdb.com/title/tt0056262/#comment

thanks for the lead.
so that is who Professor Harold Hill is---the assumed name of a con-artist musical instrument salesman

Always a pleasure to expand your cultural horizons (it is a fun show by the way, a favorite of college summer theater troupes).

Just to flesh it out a little, the Music Man sold instruments and then told his students that they could learn music using "the Think Method", which involved imaging themselves playing the instruments rather than actually practicing. Thus, the reference is in part a dig at doing theory without having experiments to back them up.