# Tag Info

1

It seems the keyword OP is searching for is AdS/CFT correspondence. The holographic principle in string theory is realized between a gravity theory in an $n$ dimensional AdS bulk manifold $M$ and a gauge CFT on an $n\!-\!1$ dimensional boundary $\partial M$. In the most famous example, the 10 dimensional target space of superstring theory is a product of a ...

1

Many popular-science authors such as Stephen Hawking or Brian Greene would try to give you the impression that if M-theory passes all self-consistency checks, there will be one "Mathematically Inevitable Theory of Nature", M-theory. Not trying to diminish the immense proportion of the human achievement a "Theory of everything" would represent, the ...

1

First let us cut away some of the meat and the bones of your question. Let us forget about thermodynamics for a minute and classical physics; however we will need GRAVITY (not Newton’s version). Instead of calling it Gravity let us call it General Relativity or (GR). We can still use the term Gravity, but when discussing Quantum Mechanics it’s better to ...

3

The immediate problem with locating our space in the string theory landscape today, is that even if you pick just one definite background geometry (definite shape for the extra dimensions, etc), you will not be able to calculate particle masses and other measurable quantities. The calculations are too difficult and there are too many unknown aspects of the ...

1

Now we have the confusion about complexity classes sorted out (at least somewhat). Do you have any reason to suggest that the problems or M-theory have an algorithmic solution which is either NP, NP-hard or any complexity class you like? I seriously doubt there exists any algorithm which would be able to "locate our space in m-theory". Additionally it may ...

0

String Theory volumes 1 & 2 by Joe Polchinski are very recommendable with many exercises. See also: Barton Zwiebach: A First Course in String Theory and (!): String Theory and M-Theory: A Modern Introduction, by: J. Schwarz, K. Becker and M. Becker, with many exercises. Regards. Pascal Kwanten

4

The AdS/CFT correspondence (or this particular, most famous example of it) is the equivalence between the non-gravitational ${\mathcal N}=4$ supersymmetric Yang-Mills theory on one side ("the boundary CFT"); and the type IIB superstring theory in $AdS_5\times S^5$ ("the bulk theory") on the other side. The equivalence is exact and the gauge theory is ...

1

Lets start with the definition of M theory: M-theory brought all of the string theories together. It did this by asserting that strings are really one-dimensional slices of a two-dimensional membrane vibrating in 11-dimensional space. So the universe which is at the microscopic level quantum mechanical, is composed of these ...

2

The root of it the so-called anomaly, which makes superstring theories mathematically inconsistent. The only dimension where it may vanish is the "critical" one (10), but that in itself is not enough if the global topology is non-trivial. And it has to be non-trivial to compactify the extra dimensions. Since the physical spacetime is topologically trivial ...

0

With an answer selected (and bounty awarded) it is time to open a community wiki for explicit references on work along the line of getting QCD + EM, or alternatively QCD alone or QCD + "4th colour" extracting the group from the extra dimensions. An early 1975 work of founding fathers of string theory claims to have a O(6) and then a SU(4) group from the ...

0

While it is certainly possible to get an $SU(3) \times U(1)$ gauge group from the metric alone, if one started with a 9d theory, there are several issues with using Graviphotons as gauge bosons in a 4d theory. Most prominently, in addition to vector bosons you will always create scalars in the adjoint from internal components of the metric, which we do not ...

2

Caveat: The first part of this answer takes a very technical stance on the BRST procedure, and additionally works with a finite-dimensional phase space for convenience. It could appear quite far from the understanding of ghosts in the average application of BRST transformations or ghosts as a tool. The general conception of ghosts There are many ...

Top 50 recent answers are included