String theory Definition and 833 Threads

Does Super String theory (attempt to) unite Quantum Mechanics and General Relativity using one master equation? Will this equation explain one grand physical principle behind all physical events? Is this equation called the Standard Model? I would like a basic answer before a more detailed...

http://arxiv.org/abs/1105.6359 Is string theory a theory of quantum gravity? Steven B. Giddings (Submitted on 31 May 2011) Some problems in finding a complete quantum theory incorporating gravity are discussed. One is that of giving a consistent unitary description of high-energy scattering...

What ist better to study, for making string theory, high energy physics and so on. Maths or Physics I think its better to study Maths, but Iam not sure, is there anyone, who has experience. Thx

http://arxiv.org/PS_cache/arxiv/pdf/1105/1105.5283v1.pdf Abstract We provide a simple transfer function that considers the impact of an early matter dominated era on the gravitational wave background and show that string theory can be tested by observations of the gravitational wave...

Hello everyone. I'm not a physicist however have been doing some research on the concepts behind dark energy and string theory and it has presented me with a question: Is it possible that dark matter could be the components of quarks that haven't pulled together to form the quarks. We can't...

String theory idea... I was wondering about how far gravitons exist beyond the membranes of the M theory. Is it theoretically possible that the gravitons leave our membrane and influence the dimention above us, and is it also theoretically possible that the reason quantum physics is so...

Edit: Here is the short (but more confusing and less rigorous) version of what I wrote below: For something to be considered a "law" it needs to make predictions which can then be tested, and if they are proven then it is considered law. However, scientists have been looking at the nature of...

This came up in another thread, but I have seen the statement many times in various places. The statement is that string theory implies general relativity i.e Einstein's field equations in some kind of a classical limit. So my question is how does that go? I am curious to see the details.

I'm a layman trying to get a conceptual understanding of string theory. It's my understanding that SO(32) & E8 are used to compactify the 16 extra bosonic dimensions in heterotic theory, is that correct? Also, it's my understanding that SO(32) is used in Type I for group symmetry. Does that...

Hi PF Does the discovery of the Higgs Boson mean anything to string theory ? Does it falscify or verify the theory, or is it completely irrelavant for the theory? \Schreiber

http://online.kitp.ucsb.edu/online/qcdscat11/ You can see it happening in these talks. For now it's just d=4 N=4 super-Yang-Mills and d=4 N=8 supergravity, but there is every reason to think that the relationships being discovered there will be extended (in more complex forms) to other gauge...

I'd like to hear what people have to say about the following paper, which is way beyond my level knowledge, but could be exciting(?): http://arxiv.org/abs/1104.2302

Instead of thinking of non - critical and critical strings, why not thinking about those as 1 aspect of the same theory, where the non - critical character provides a kind of virtual dimensions. Maybe this could somehow guide a preferential choice of the vaccuum? For example, this theory...

In post #549 here I answered: And then I was surprised by the comment of Tom, asking how the pairing was done. Well, I thought that I had discussed it in some thread in BSM, but after looking at it, it seems that I did only a few sparse remarks here and there. On other hand, people was not...

First off, I've always been under the impression that string theory was crackpot (with absolutely zero reasoning on my part, just from authority) but the way I've seen it discussed here in the last years (and I've heard the LHC has some experiments pertaining to it) maybe my impression was...

Okay so if we assume strings (as described in superstring theory or M theory) are about the size of plank length, then if you divide the estimated size of a quark or atom by planks length, shouldn't that give you the total amount of estimated strings in a quark/atom?

I always hear that these two things are incompatible but I never really hear why. The most I know is that QM assumes a quantized spacetime whereas GR assumes a dynamic one, but I don't really understand if this is correct (nor do I get what that really means). I don't see how GR would fail...

Apparently, it is difficult to reconcile a champion of this theory and the opposition. I would enjoy hearing views on this, since I am convinced the general scientific community is above condemning those with different approaches/beliefs to those of the mainstream. So, who believes string...

Is it proved that the bosonic string and superstring partition functions are modular-invariant for arbitrarily high loop order? If not, how many loops have been analyzed?

Hi all, I have been reading a bit upon LQC and from what I understand this theory of QG makes some fundamentally different assumptions from string theory but has there any work been done that relates these two theories? I tried to look on google but no good results turned up there, ergo, I...

So I have a few questions about a string theory course I am taking, although I guess the questions are largely on indices/QFT stuff! (i) Consider the expression \bar{\psi}^a \gamma^\mu \partial_\mu \psi^b \eta_{ab} we were going to take the transpose of this and it was said that the transpose...

If string theory asserts that a particle can be in more than place and theoretically there are different realms / universes etc. where this occurs but each one is different, how do these differences occur? If it's based the assertion that complete hard determinism does not exist (for every realm...

Hi all, I remember in the Elegant Universe (the documentary), at some point the following lines were said: "So what exactly, in nature, sets the values of these 20 constants so precisely? Well the answer could be the extra dimensions in string theory. That is, the tiny, curled up...

I'm reading this: ==quote== Einstein's theory of gravity, General Relativity, and our theory which governs the sub-atomic world, Quantum Theory, give seemingly inconsistent accounts of the nature of time. According to General Relativity, each observer will have a separate notion of time...

A summary of connections between String theory and Relativity. Can you please explain it in a paragraph or post a link of a webpage that explains this concept specifically (High School Physics Level Please!)

Considering that the smallest particles in nature are supposed to be strings, which are donut and line shapes. And the poincare conjecture says the simplest shape in nature is a sphere. wouldn't it make sense that the true fundamental particles are sphere shaped and that if they combine to form...

since the strings are no longer points, the UV divergences are avoided from calculations, but what happens with IR divergences ? ,

The answers will probably be "it ain't as simple as that" but here's trying, anyway. 1. Is current thinking that strings have to wind "around" something? If so, must the compactified space have at least one hole? 2. With just a single hole, presumably there can be just one topologically...

Brilliant forum, wish i'd spent time browsing it years ago. In my layman's "understanding" of string theory six dimensions are compactified and usually presumed to be of very small size. My questions are: 1. Is there any mathematical or (better still) physical reason why this space does...

I have a few questions on non-critical string theory... terminology: 1: Are "Gepner models" a subset of non-critical string theory? technical: 2: Given a set of spectrum, are there ways to construct a non-critical string theory with enough symmetries so that the CFT becomes minimal and...

Hi people I have 2 questions about string theory 1-I've read that string theory tells us that we can ignore the fluctuations of space time in sub Planck scale and so enables us to use general relativity in such small scales.Also we know that GR says Gravity is not a force but a cause of...

I often hear people talk about string theory being the hardest branch of theoretical physics, and require a PhD to even understand the basics. I've even heard of people saying it's getting too hard for humans, much like quantum mechanics is too hard for cats. So to put things into perspective...

Is there any relationship between String Theory and ZPE? I mean, does ST offer anything new, any new reason to ZPE? Thanks!

In the other day's lecture, my professor was going over gravitational potential energy and on a side note he added that there is a theory (though not fully accepted by many people as a theory) out there saying something about another dimension, with tiny strings acting on objects, and that is...

I have come to the conclusion that my ideal area of scientific persuit is the area of theoretical physics in specific string theory. Recently i have been researching on which field of theoretical physics i have the most interest in. My area of interests are most simply put the most fundamental...

Question on Witten's paper: "Perturbative Gauge Theory As A String Theory..." Hi guys, I have a question regarding formula 2.12 of Witten's paper hep-th/0312171 "Perturbative Gauge Theory As A String Theory In Twistor Space". He just states this formula but i don't really understand his...

Ok, i have come to a realisation that my interests revolve not around pure mathematics (as i once thought) and more around theoretical physics, some people would claim that they merge into one at times, and that leads on to my question. If i wanted to be a theoretical physicist (rather than an...

Hi everybody, i'm a phd student in theoretical particle physics... so for my studies I'm learning a lot about qcd and phenomenology, but don't know anything at all about string theory etc... Even though I'm quite skeptical about string theory and the not so many prediction it gave, still i...

Hi In string theory, as I understand it, a frequency between two points creates a particle, different frequencies make different particles. If say the points were arranged in a cube there would be 8 points with twelve strings between them, would this lead to twelve particles or would one...

From what I've read, String Theory is a theory of everything, unlike some of the other quantum gravity theories. That means that String Theory explains other particles and fields including gravitons. So String Theory is a quantum gravity theory because it includes gravitons. But I was...

What is wrong with the following reasoning? String theory has diffeomorphism invariance. Since time reversal is a diffeomorphism, string theory is time-reversal invariant. Therefore T and CP violation can't occur in string theory, and string theory can't describe the standard model in the...

http://www.youtube.com/watch?v=E7FV9aaiwKQ&feature=related" , what mathematical formula are they referring to? (Which is a mathematical formula that describes the strong force and stood at the beginning of string theory research according to this video.) thanks

If I understand Brian Greene’s argument (in The Elegant Universe, and repeated elsewhere) for the Planck length being the minimum measurable length based on T-symmetry in string theory, it goes something like this: There are two ways to measure things, one with vibrational energy v and one...

In another thread: https://www.physicsforums.com/showthread.php?t=436080" a discussion came up relating to the validity of String Theory and the specific thought that, if nothing else, it has helped us to better understand the issues of quantum gravity. I wanted to start a new thread to adress...

FIRST: Please, I don't what this to be a String Theory bashing thread. I've seen and even participated in plenty of those. I think that String Theory is interesting and that if and when we find a Theory of Everything that it is likely that String Theory will at a minimum have pointed us at least...

Hi, guys. I want to do some research on quantum gravity. I know that there are two theories achieving some success in this direction. Do you know something about that? I want to learn something about that. Thank you!

Can some one point out papers that discuss non-perturbative aspects of string theory that have been derived from perturbing gauge theories through the gauge/gravity duality? I can only find papers discussing the other way around - be it in QCD or CMT.

As I understand it, string theory only has one coupling constant, but there is a whole discrete landscape of false vacua, each of which gives different values to the quantities, such as coupling constants, that are taken to be fixed inputs to the standard model. Since the false vacua are...

"Four-qubit entanglement from string theory" This paper Borsten et al., "Four-qubit entanglement from string theory," http://arxiv.org/abs/1005.4915 (published in PRL) is being described http://www.sciencedaily.com/releases/2010/09/100901091938.htm in the popular press as a proposal for an...

This article looks very interesting and shows how there is still experimental hope for String Theory: http://www.physorg.com/news202553083.html