Do I need to study the "Standard Model" before studying String Theory?

Question

After this semester, I'll have a background up to a first course in QFT (first 5 or 6 chapters of Peskin and Schroeder).

The next step in QFT will be something specific to the Standard Model (Elementary particles, QCD, etc).

Is that needed before going to study String Theory or not?

This post imported from StackExchange Physics at 2014-03-12 15:55 (UCT), posted by SE-user student1

Comments

No it's not necessary, but the more you know about the standard model, the better.

This post imported from StackExchange Physics at 2014-03-12 15:55 (UCT), posted by SE-user joshphysics

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Well, in general, yes the more I know the better, but let's be specific to the ST, is the more I know about SM the better I understand ST ?

This post imported from StackExchange Physics at 2014-03-12 15:55 (UCT), posted by SE-user student1

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@abumofeed: The more you understand the standard model, The more you understand why you need ST.

This post imported from StackExchange Physics at 2014-03-12 15:55 (UCT), posted by SE-user Dimensio1n0

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@abumofeed The whole of Peskin and Schroeder is hopelessly inadequate for a good grounding, let alone the first 5-6 chapters of it. However if a thorough introduction is all you want with special emphasis on QFT's link with String theory, try A. Zee's 'QFT in a nutshell'.

This post imported from StackExchange Physics at 2014-03-12 15:55 (UCT), posted by SE-user dj_mummy

Answer 1

If one is a mathematician one can study any set of theories to his/her heart's content and end up with a QED at the end.

Physics is about studying understanding and modeling nature ( Physis in greek) preferably with mathematical models which are predictive of new behaviors.

The standard model (SM) is one such mathematical model . What does this mean? It means that it is a shorthand for a huge number of physical data painstakingly gathered from individual experiments. It fits the results and all the predictions it has given for the LHC are within the experimental errors.

Why are physicists interested in String Theories and not satisfied with the SM? Because they believe that all interactions in nature should be modeled by a single model and the SM describes and predicts data only for three out of the four. Gravity is not within SM. For many years now theoretical physicists have been studying various mathematical models that will include gravity in one unified theory with all four interactions.

String theories are the best candidate for modeling all interactions because their group structures can accommodate the groups of the SM, and thus all known data can be embedded in a string theory model.

If you do not know in depth what your are trying to model, you may be a good technician in mathematical modeling, but not a good physicist with a physicist's intuition. It all depends on your further goals, if you want to be a research physicist or are just studying some physics for other requirements. If the former, yes the SM course is necessary.

The work for theoretical physicists in string theory models lies in finding which specific branch and finally form of a string theory embeds best the SM and predicts new phenomena to be found and studied. If one has no data bank of the known phenomena and the way they are connected mathematically one will have developed no intuition on finding the needle in the haystack of string theory possibilities, or be able to suggest experiments that will lead to a validation for a specific ST model..

This post imported from StackExchange Physics at 2014-03-12 15:55 (UCT), posted by SE-user anna v

Comments

Thanks, appreciated. Actually I am on my way to be a Condensed Matter Experimentalist; thus I would like to study ST only for my interest. On the other hand, QFT is necessary for my study.

This post imported from StackExchange Physics at 2014-03-12 15:55 (UCT), posted by SE-user student1

Answer 2

Just a different way to phrase anna v's answer

The Standard Model can be imagined as a model formed by combining certain quantum field theories and fine - tuning to match experiments.

The keywords are "to match experiments". This means that the Standard Model agrees with experiments (to a large degree, anyway). Therefore, it is an accepted theory that describes our universe, along with a certain sort of model based on General Relativity.

String Theory, on the other hand, is not completely experimentally verified. Unlike the man - made (i.e. fine - tuned and all that) Standard Model, String Theory is a natural theory, made by building on fundamental postulates, and hoping that it wiill match experiments. If it doesn't, it will just be plain mathematics, not physics.

And if it does, it is Physics.

SO, if you want to get the physical insight, or in other words, if you want to study string theory in a physicist's point - of - view, as opposed to a mathematicians's, you'll need to study the standard model first.

This post imported from StackExchange Physics at 2014-03-12 15:55 (UCT), posted by SE-user Dimensio1n0

Comments

I agree, thank you!

This post imported from StackExchange Physics at 2014-03-12 15:55 (UCT), posted by SE-user student1