String theory Definition and 782 Threads

Hey all, Firstly I would like to say that I am fully aware that there is a part of the site related to string theory and other related topics, but I feel as this is such a layman question, it probably belongs here. Correct me if I am wrong. Okay, I am sick and tired of people in my...

I've read in a couple books (e.g. in Lee Smolin's three roads to quantum gravity) about the possible union of LQG and string theory. In other words, that string theory and LQG can possibly be reformulated into a single TOE. I've been unable to find anything more on this idea through google and...

What is the length of a typical course on string theory?

I hope this not a dumb question. In t.v. programs I see about String Theory there is something vibrating or oscillating. What's vibrating or oscillating I don't know, but what is causing the vibration or oscillation.

I know string theory is not proved yet.Now Biggest hope is LHC. But theoretically has string theory solved all problems or still there are unsolved problems in physics and what are those?

Do you think physics departments should give equal time to LQG and string theory? Currently, the top physics research departments at the best Universities, from Princeton to Harvard to Stanford to Rutgers all employ string theorists in various capacities. When I say equal time, I am...

Hello all. I am a layperson that is very interested in science. I am particularly intrigued with what results the LHC will produce and how they affect the various existing theories. I was thinking that a central thread that links to and discusses various predictions on what the LHC will find...

I am no expert in the string theory, but I was curious why it has so many dimensions. After thinking about it, I think I know why. It has to do with the assumption of 2-D strings. This can be understood with an analogy. We can make any color using combinations of red, blue and yellow. If we plot...

Can anyone reccomend a Beginners Guide kind of thing for string theory? Basically trying to get started off, what's the best book(s) for me to get? (Preferably cheaper ones, I am kind of cash strapped blown my physics books money for a while)

Is string theory deterministic? So if a supernatural mind knows all the physical information in the universe at a specific moment then he will exactly know (using string theory) what will happen in the future. If string theory is not deterministic, should the Theory of Every Thing be a...

My understanding is the formulation of string theory requires n-dimensions for the satisfying degrees of freedom of a string. However, why is typical 3d spacetime insufficient in providing the appropriate degrees of freemdom? Is there any functional model of string theory which doesn't implement...

I asked this in sci.physics.strings and I haven't gotten an answer yet, so I hope you'll oblige me.

While I cannot now offer a page #, Smolin in TWOP offers his assessment of string theory as a theory of QG by pointing out that while GR does offer quantitative predictions of time dilation effects, string theory does not (if I understood Smolin correctly). Any comments?

Hi All, I know virtually nothing about General Relativity except that which is shown on the usual PBS channels and would like to delve into it in more depth. My level of understanding physics is at the upper undergraduate to lower graduate level. Could someone recommend a textbook for me...

How can string theory explain the results of Bell inequality experiments and experiments of similar inequalities?

Are other worlds in the MWI existing in adjacent branes? If one could bend the rules as currently defined, and one wanted to journey to another world under the MWI idea, how would you accomplish it? Is this ever discussed? Would it require fabulous amounts of power? Creation of a worm hole...

Inertia explains some different aspects of motion with great accuracy, but as far as I know, there isn't really underlying explanation of why inertia works. Could the answer to this question lie in string theory?

I have just seen some pretty pictures of flame fractals with reference to string theory. I was just wondering if or where they fit in. thanks :smile:

Hey folks, Can somone explain what is meant by a 'sector' in string theory, or provide links/refs. I've tried a search on google and xxx.lanl.gov but nothing very useful turns up. Also, what is the N-S N-S sector (I know it stands for Neveu Schwarz). I think its a description of fermions...

First of all, I don't know anything about mathematical physics whatsoever. I am not well aquainted with it. So please forgive me if I am misinterpretating something. My question has to do with MOND and TeVeS. If this theory happen to be true and Gravity is different or incosistant in huge...

Witten argues one of string theories great achievements is that it shows that topology can change. Which is fine, but is there any observational evidence (i.e from astronomy or HEP) or any experimentally testable predictions on topology changing? Is there any physical evidence for topology...

I've been hearing a lot of talk lately regarding the validity of String Theory. There have been a lot of people that I have met that seem to think that the entire theory is completely wrong. Is there something I've been missing out on? I've always been under the impression that string theory is...

Kenneth Lane "string theory is not physics" Who is Kenneth Lane? wikipedia states "Kenneth D. Lane is an American physicist and professor of physics at Boston University. Lane is best known for his role in the development of extended technicolor models of physics beyond the Standard Model...

This isn't so much a question specifically as a point that came up in my mechanics class... so sorry if I'm posting it in the wrong place! In a basic mechanics class; we were finding the frictional force on a box by thinking about someone moving it by pulling an attached string. Someone in...

I was talking to a friend of mine the other day and he mentioned string theory to me..I had no clue what it was so I looked it up but didnt exactly understand it. My friend tells me it's a theory of parallel universes? He said something like there are different dimensions with different time...

I've always heard that 2007 was the year that may falsify string theory at a large collider in CERN or somewhere. 2007 is nearly over. I haven't heard anything about it. What has happened over there?

Envy of the 3D modeling abilities of Hans, I have tried mine. So, new thread for string related plots. In this post, you can see interacting strings. Really you can not guess if each vertex is a fermion or a boson in a superstring theory; I can not see how to tell it in pictorial way. So even...

So after watching the tv show titles "Elegant Universe" narrated by Brian green. and after reading his book with the same name among other books of similar interest, I've had a brain storm. According to M-theory strings are opened ended strings that are connected to the universe at each end as...

In the official string site, why didn't they recommend studying integrable models in the mathematics section? String theory itself is an integrable model, no?

http://www.math.columbia.edu/~woit/wordpress/ "Comment on Technicolor/Extended Technicolor Models October 26th, 2007" very brief excerpt "I would like to respond to Eric’s recent comment on Oct. 23 in which he said that “technicolor models were..eventually rejected due to some serious...

String theory seems to be an over popularised topic with many talented people working on it already. How tough is it these days to publish in this field (on the mathematics/theory side rather than applying string theory to experiments or what not).

Lisa Randall said "string theory reproduces GR in 10 dimensions" Does string theory gravitons have 4D GR as its low energy limit? I know that its lowest mode vibrations corresponds to a massless spin-2 particle, the graviton. I know GR in 4D can be extended with susy. Does it reproduce...

How is this field looking? What topics does it have? Who are the experts in this field?

Homework Statement Can someone define the phrase "quantize a string" as seen at http://books.google.com/books?id=XmsbvP1uUeIC&pg=PP1&dq=zwiebach&ei=uCgdR7rYLo-8pgL3sLygAQ&sig=Eqnkxjj7B9gc4-nig1fgUkk7AqQ#PPA206,M1 ? Homework Equations The Attempt at a Solution

If a particle is point like, then point x\in\mathbb{R}^3 specifies the particle's spatial configuration, and the quantum mechanical wave function for the particle is \Psi:\mathbb{R}^3\to\mathbb{C} The spatial configuration of a closed string with fixed length L can be specified with a...

Hello, I have read a few books on the subject of String theory, including The Elegant Universe and Fabric of the Cosmos by Brian Greene (that guy is AWESOME!). Anyway, Mr. Greene may have answered my questions somewhere in his books, but the other day, I heard someone say that strings are tiny...

How likely is it that string theory will be the final complete theory? I've heard lots of negative things about it. Has it been totally written off? Has it been reduced to a maths theory only? By string theory I mean all the versions of it like superstrings etc.

Homework Statement One thing that has been bothering me about the light-cone gauge that Zwiebach uses is that we have equations such as 9.63 and 9.71 in which X^+ and X^- are given by completely different expressions. I am not sure why this makes sense physically since we can interchange...

As some PF followers are aware, last year I have been wondering, against my own preferences, if there was a possibility of using string theory straightforwardly (no AdS/CFT) in the QCD word. Today I have abstracted my comments into sections 3 and 4 of http://lanl.arxiv.org/abs/0710.1526...

Do MWI and String theory conflict? (sorry--I'm a layman) Hey, Well basically I've been skimming over lots of different multiverse theories and as I don't have a science background (total layman) my question is basically can these two theories co-exist or do they not leave room for each other...

Homework Statement http://books.google.com/books?id=XmsbvP1uUeIC&pg=PA113&dq=stretched+string+and+a+nonrelativistic+limit&ei=N9XsRqHcE42EpgKaxsi5Dw&sig=6cUrZKqmPMoe0QBRTSYNnipNRw4#PPA114,M1 In the solution to problem 6.3 shown in the attachment, can someone explain to me why d\vec{X}/dx was...

Homework Statement Sorry this page is not part of the free preview but I would recommend that everyone buy their own Zwiebach (or download it illegally if ethics don't stop you). Anyway, on page 109, can someone help me figure out where the last equality in equation 6.79 comes from...

Homework Statement I am learning about static gauges in string theory from Zwiebach chapter 6. Is it true that a static gauge is simply a parametrization where time is the parameter? That seems much too simple. Homework Equations The Attempt at a Solution

Homework Statement Zwiebach QC 6.4 Why is \frac{\partial}{\partial{X^{\mu}}} \left( \frac{\partial X}{\partial{\tau}} \cdot \frac{\partial X}{\partial{\sigma}} \right) ^2 = \left( \frac{\partial X}{\partial{\tau}} \cdot \frac{\partial X}{\partial{\sigma}} \right) \cdot...

Homework Statement I saw the following equation in my (Zwiebach page 83). 2 ds \delta (ds) = \delta (ds) ^2 where delta is the variation from variational calculus and ds is the Lorentz invariant spacetime distance. It seems like they took a derivative from the right to the left but I am...

Homework Statement Zwiebach QC 5.2 Tau is the parametrization of a worldline. p is the relativistic momentum Show that \frac{ dp_{\mu}}{d \tau'}} = 0 implies that \frac{ dp_{\mu}}{d \tau'}} = 0 holds for an arbitrary paramter \tau'(\tau)) What needs to be true about the derivative of tau'...

Laymans question: 2 Why is string theory... ...a theory if thereis no empirical evidence for it ? The only way I can understand there is a difference between String theory and say "inteligent" design is that string theory works out mathematically. ie That we can become aware of things...

is super symmetry real or has been predicted by string theory?

Apparently Sylvester James Gates Jr. has formulated a variation on string theory that does not require extra spatial dimensions (or temporal dimensions for that matter). He indicated in his lecture at the 2005 Nobel Conference at Gustavus Adolphus College that this model has not received nearly...

I once got into a very heated debate with some string theorists, about string theory, saying that I doubted it would ever pan out, not that it may never have any use, but questioning why it gets so much attention and yet has nothing to show for itself? now it is impossible to say never but that...