Why String Theory Still Offers Hope We Can Unify Physics | Hacker News Reader

Why String Theory Still Offers Hope We Can Unify Physics

smithsonianmag.com

27 pointsThibaut12 comments

This was discussed two weeks ago (https://news.ycombinator.com/item?id=8779532). The title was changed at the source since it was originally too bombastic.

Just once it'd be nice if the author was somebody other than Brian Greene. Seems like he's the only advocate for string theory these days.

I don't even bother reading string theory articles even physics articles for that matter. They are just filled with useless analogies that don't make anything clear.

Until I get around to finishing my QFT text I just accept that I don't really care to read low information low precision pop sci.

Yeah, same here. It's unfortunate really. Which QFT text are you reading? I've just started Weinberg's book.

I'm working my way from the very start of my physics education with classical mechanics. What are the prereqs for QFT?

You should probably have at least a good understanding of non-relativistic QM and special relativity. For the math parts a little bit of complex analysis helps, but any good book will explain the relevant parts.

Weinberg is pretty good. I also like Schwartz's new book, though I'm biased because I took his QFT class. The other book I really like is Peskin and Schroeder.

Srednicki's

If you don't have expertise in physics, Weinberg is extremely difficult to read---he uses notations that nobody else does, and its full of technicalities.

A much more approachable first text for QFT is the book by Zee.

at the end of the article he does express some doubt about the thoery

Yeah, well, string theory would get a lot more advocates if it would make a damn prediction we can actually test. I mean, if the point is to unify quantum mechanics with general relativity, shouldn't the string theorists look for any experimental domain where those two sets of physics will both operate, start predicting, and start testing?

Problem is, at this point I wouldn't be surprised to hear someone say that string theory allows for gravity to operate by the Divine Will at the Planck scale -- some real number encoding the entire Bible in quaternary numbering is probably within the allowed parameter-space for some string theory. It just doesn't seem to meaningfully constrain our potential observations.

This is much easier said than done. Let's imagine that, for instance, the way to have gravity comport with the uncertainty principle starts with verifying the graviton doesn't exist, and that gravity is a non-discrete field effect (contrary to electric fields -- this is unlikely to be true or to help, but is an example of a statement we can evaluate for electric fields, which are similar but better understood). The experimental accuracy you would need for this is astounding, perhaps impossible except at exceptionally low temperatures or other extreme conditions.

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