Superstring theory Definition and 24 Threads

Usually, I saw that string theory (perturbative, or matrix models) are made in a fixed background. Even if you consider that the metric is quantized and etc. there is an apparent physically motivated need for making a sum over topologies (manifolds, conifolds, orbifolds, and etc), for example...

Are there alternatives to Calabi Yau spaces describing dimensions in superstring theory? If yes, what are they? If no, why?

A quick question: are there known solutions to superstring theory that reproduce all the properties of the standard model at low energy? I mean: three families, gauge groups, pattern of symmetry breaking, correct quantum number assignments, etc. It may be that the question is not precise...

Can someone at least gives a summary of the constrains in the E8xE8 heterotic superstring theory? Many sources are mostly outdated that was written decades ago when not much research were done yet in superstring theory. So is E8xE8 already refuted? Or to what degrees and what constrains? I need...

Hi everyone. I heard that there are several theories or hypotheses to quantize gravity such as superstring theory, loop quantum gravity, etc., and I believe none of them are conclusive (that's what I heard). So, here is my question. 1) Is it because there are no experimental results which prove...

I don't know much about gauge/gravity duality but I know that its a conjecture coming from superstring theory and one of its examples is AdS/CFT duality. Now I have two questions: 1) As I said, I know that gauge/gravity duality and superstring theory are related but I don't know how much. Is it...

If superstring theory works, has no infinities, etc. Then what is wrong with it? It must describe some Universe unless there is a contradiction in it somewhere? If it predicts all particles and gravity what is missing from it? Is it not compatible with cosmology for instance? Is Superstring...

I was talking to a friend of a friend who is a physics professor, and I asked him what the best way to learn (the basics of) string theory and he said that this book (Superstring Theory Greene, Schwartz Witten) is the best and the one that everyone seems to use. So I went out and brought it...

lately higgs is found than how about string theory example string's position strings will destroy??

I'm trying to understand what I have just learned. So some sort of browser based code or binary was discovered in equations for super-string theory. I have a few questions since I am very confused. If code was created by Claude Shannon in the 1940's, then how could it be in this code? Does...

Homework Statement Let \begin{equation} \delta _{1} \, and \, \delta _{2} \end{equation} be two infinitesimal sypersymmetry transformations on xμ compute \begin{equation} [\delta _{1}, \delta _{2} ]x^{μ}. \end{equation} Homework Equations The commutator is: \begin{equation}...

This paper may be intersting: http://www.springerlink.com/content/d3182t263w74267g/?MUD=MP On the Foundations of Superstring Theory Gerard ’t Hooft Abstract: Superstring theory is an extension of conventional quantum field theory that allows for stringlike and branelike material objects...

Gravity with spin excludes fermionic strings Abstract: The existence of intrinsic spin of matter requires the metric-affine formulation of gravity, in which the affine connection is not constrained to be symmetric and its antisymmetric part (torsion tensor) is a dynamical variable. We show...

Are these 'strings' the size of planks constant? Nothing can obtain a size smaller than planks constant...right? What I am trying to figure out is if saying strings were the size of planks constant were a good approximation if the size of them

Hi there, I 'm currently reading topics relating to type IIB superstring theory. One of the things I am always confused with is Groups. I looked on various websites including Wikipedia but I still haven't quite got it. Could anyone please give me a nice introduction about Groups? What are...

What is meant when one says that everything we see is the lowest vibrations of the strings (According to String Theory)? I understand the very fundamental concepts of this theory, like how it only works in 10 dimensions, but the above statement confuses me.

Can general relativity derive from superstring theory?

In Szabo's book on string theory he calculates the vacuum to vacuum one loop (genus one) diagram. The contributions can be organized according to different spin structures (periodic or antiperiodic along the two cycles of the torus). The spin structures are (+,+). (-,-) , (-,+) and...

What's the difference between string theory and superstring theory? Are they two different names for the same thing? Which one came first? Which one is more popular?

Help me to introduction in superstring theory what is it ?

hi, i am new and have a paper due on tuesday about the integration of superstring theory into cosmology for my astro class. I am not very deeply read into either of these topics so if anybody wants to help me out with any information, that would be great. thanks

I want to study superstring theory (and maybe find the theory of everything). Even if I don't end up making that discovery I still want to be able to understand the theory or the closest humanity ever comes to a theory of everything. I've been looking at the math requirements but a lot of...

I was wondering how a string could be a one dimensional vibrationg loop? I am still trying to remove myself from the 3 dimensional ideal of our world, however how can anything have only one dimension, for then it would imply that it has neither of the other two dimensions and therefore wouldn't...

So far in this past century, the theory of the superstring has held most promising oppertunities for unifying all quantum mechanics. However I noticed some very imediate flaws that eliminate the purpose of the theory. The theory is that everything is made of one-dimensional strings, whose...