Hello,

I have been working on devising a few experiments, which I will include
in the fnal MDT paper:

http://physicsmathforums.com

Speaking of experiments, does String Thoery have any experiments by
which it might be tested?

Why are all other physicists held to higher standards than string
theorists?


http://www.math.columbia.edu/~woit/b...es/000219.html
Is String Theory About to Snap?
The August issue of Discover magazine is out, with a cover story
entitled "Is String Theory About to Snap?". The editors of the magazine
describe how they recently became aware of the controversy over string
theory when they organized a celebration of Einstein in Aspen last
summer. They quote Lawrence Krauss as telling them "String theory may
be in a worse position now regarding being testable than it has been at
any time in the past 20 years." To get a response to this, they asked
Michio Kaku to write something for them. They refer to him as a
"cofounder of string theory", which I suspect some people might object
to. Presumably they meant to repeat what is in their profile of him,
which calls him a "cofounder of string field theory."

Kaku's article is entitled Testing String Theory, and is a thoroughly
intellectually dishonest piece of writing, designed to mislead anyone
without expertise in what is at issue here. He succeeded in misleading
whoever wrote the blurb for the article which goes: "No experiment has
ever allowed us to test whether any of the assumptions of string theory
are true. That is about to change." No it's not. None of the
experiments Kaku mentions will "allow us to test whether any of the
assumptions of string theory are true".

As I've explained in detail on other occasions, the simple fact of the
matter is that string theory does not make any predictions, unless one
adopts a definition of the word "prediction" different than that
conventional among scientists. A scientific prediction is one that
tells you specifically what the results of a given experiment will be.
If the results of the experiment come out differently, the theory is
wrong. String theory can't do this, since it is not a well-defined
theory, but rather a research program that some people hope will one
day lead to a well-defined theory capable of making predictions.

At places in the article Kaku qualifies his claims of "predictions",
for instance saying near the beginning of the article that certain
experiments "could provide significant evidence that would support
string theory" (note all the qualifiers in this phrase: "could",
"significant evidence", "support") but that "the rub is that all the
new evidence, no matter how compelling, will still provide only
indirect proof." He soon abandons his qualified language and starts
talking about the following topics:

1. Gravitational waves: He says of gravitational waves created in the
Big Bang: "String theory predicts the frequencies of such waves", and
that this prediction will be tested by LISA. I don't know specifically
what he has in mind here, but I know of no way to use string theory to
make a specific prediction of the spectrum of gravitational waves that
LISA will see. The only things he mentions are inflation and epkyrotic
scenarios, the first of which has nothing to do with string theory, the
second very little.

2. The LHC: Kaku discusses the possibility that superpartners exist,
but does note that you don't need string theory to have these. He also
discusses possible Tev-scale particle physics effects of extra
dimensions, without mentioning that string theory makes no predictions
at all about what these extra dimensions are like, or even what their
size is. There is absolutely no reason other than wishful thinking to
expect extra dimensions in string theory of a size invisible until now,
but visible at LHC energies.

3. Laboratory tests of the inverse-square law: Kaku claims: "according
to string theory, at small scales like a millimeter, gravity might hop
across higher dimensions and perhaps into other, parallel universes".
This is a load of nonsense. String theory predicts no such thing. It
may be consistent with this, purely because it is consistent with
anything. He does go on to say "Perhaps the additional dimensions would
show up only on smaller scales -- string theory is still somewhat vague
about this prediction." "Somewhat vague"??? As far as I know string
theory makes no prediction about this at all, except that most string
theorists expect effects to show up below 10-33cm, not 10-1cm.

4. Dark matter searches: according to Kaku "Once particles of dark
matter are identified in the laboratory, their properties can be
analyzed and compared with the predictions of string theory." Only
problem is string theory makes no such predictions. He's talking about
neutralinos, but in string theory the neutralino mass could be
absolutely anything. After discussing these string theory"predictions"
about dark matter, he goes on to speculate that maybe there is no dark
matter anyway, just "huge clumps of shadow matter in a parallel
universe, causing our galaxies to form in mirror-image locations", then
admits that such an idea is incapable of ever being experimentally
tested.

After going through all this, he saves the real kicker for the end:
"Some theorists, myself among them, believe that the final verdict on
string theory will not come from experiments at all". So he doesn't
even believe in any of the nonsense he has been spouting. He admits
that "The principal reason predictions of string theory are not
well-defined is that the theory is not finished." So the earlier talk
of "predictions" is now no longer operative. He goes on to invoke the
pipe dream that someday someone will come up with a finished version of
string theory that will predict precisely the standard model,
neglecting to mention that there's not the slightest evidence that this
is a realistic possibility. On the contrary, all the evidence now
points to the conclusion that, if string theory makes sense at all, it
has an infinity of different vacuum states, and is probably a radically
non-predictive theory. Impressive that Kaku could write a whole article
about the prospects of string theory, and somehow neglect to mention
the huge and very relevant controversy surrounding the idea of the
landscape. Do you think he hasn't heard about it?

http://www.math.columbia.edu/~woit/b...es/000219.html