The Tartan

By Eshaan Joshi

I never really knew how to start this one. It’s weird, because it really shouldn’t be that difficult. It’s just physics — string theory, in particular. It’s been well documented. There’s academic literature. There’s a lack of results. There’s so much to talk about when it comes to string theory. There are literature reviews and stodgy old academics complaining about funding and grants, and there is so much hard evidence to present — string theory was worthless. It was all worthless. 

But that can’t capture what string theory was — it can’t capture the sort of horizon it presented. String theory was something sold to so many as the new science. It was going to change the face of quantum mechanics altogether. It was going to be the next big thing. It was the promise of a million new theories that would somehow describe the last great cliffs of science. The unified theory of everything, the new field of particle physics. It was hope, as the strange quantum musings of the 20th century were slowly being forgotten.

It’s the hope that gets ya, huh?

I guess it might be a good idea to explain what this all is. String theory was a novel way of looking at the landscape of particle physics, the field of physics focused on subatomic particles and their nature. There are many complexities that arise when you get that small, and string theory hoped to try to fix them all. It seems, at its face, simple: replace the zero-dimensional, point-based concept of particles with these one-dimensional strings. As you expand out on this idea, it starts to take hold as a full framework on strings and their interactions and propagations. It becomes a way to describe the nature of reality, and over half a century was spent working on it.

See, that was where the problems all started. It’s a beautiful framework — one I can barely describe — but it was so difficult to nail anything down using it. It was really just a hand-wavy way to cover up the many holes and unexplainables in “regular” particle physics. Strings gave you a single, unified particle that created everything — a God that gave you the seven-day framework to explain the existence of everything. A string meant the differences between the force-carrying bosons, and the matter-forming fermions could be easily explained away. It simplified the quirks and irregularities of non-integer spin, and made it so easy to understand everything. It came with a companion — we could throw out the strange tachyons that seemed to mess with our standard model, and replace them with strangely named “supersymmetric” versions of the particles that we already knew. And who doesn’t like symmetry? But all these cool predictions and ideas and frameworks came with a major problem — how the hell do we compute string perturbations? Can we actually do the math?

Short answer? No. Long answer? No. String theory didn’t come packaged with a billion computations we could put to the test, but a bunch of ideas for how we could do those computations. We had no fundamental theories. We had, at best, a few heavy-handed guesses.

Our second problem came courtesy of “Flatland.” Well, not exactly, though that mathematical book is one I’d highly recommend to anyone with time to waste. In order for us to have enough strings to actually describe the entire universe, we needed to do the opposite of “Flatland” — instead of going down to two dimensions, we had to jump up a couple. By “a couple,” I mean four — to the sixth dimension. See, in the sixth dimension, we can actually fold and maneuver and modify strings in such a way that we can get the massive number of strings necessary to cover our bases. Problem solved! We just need a way to test a six-dimensional space.

The astute among you might have realized we don’t have a couple extra dimensions casually lying about. If you do, please return those to the Physics Department, they’ve been looking everywhere for them. Without the ability to conduct six-dimensional tests, it became exponentially harder to actually operate with and understand string theory. But hey, surely we have a way foe—

I was going to try to write a funny sketch to lead into this point, but it didn’t really work via text. Either way, guess what? Scientists love arguing. Now, we’ve got five whole versions of string theory, each with slightly less intelligible names than the last. And we don’t have any experimental methods to verify them — just side-effects that we may or may not see. We can’t do string theory. 

Oh, and supersymmetry, string theory’s sexy friend that we thought might help? We built big colliders and experimental setups to look for them. And we kept looking, and at this point we’ve ruled out so many versions of supersymmetry that the field itself might just die within the next few years. Nobody wants to do a Ph.D. in something that doesn’t even make sense as it stands. As it is, supersymmetry is dead. And if supersymmetry is dead, where does that leave strings?

It’s all bad, all the way down. Peter Woit, a man who calls himself a “physics watchdog,” says string theory is “not even wrong” (incidentally, this is the interview that inspired me) and that’s… well, it’s really bad. It’s not that string theory is right or wrong, it’s unprovable, unsolvable, untestable. It’s… nothing. And to the many scientists who slaved away on it for a half-century, it might just have been a career killer. 

Scientific ideas die all the time. I’ve waxed eloquently on the fact that string theory is useless, but plenty of things just die.

This one hurts, though. String theory was for so long the last great discovery we needed to finish physics. Not really finished, actually, but it gave us something to look forward to when we wanted to solve the standard model. String theory helped us try to understand weirdness, and it gave us hope that everything was, eventually, going to come down to a few, distinct laws of the universe. It was the goal of physics for so long, packaged into one, possible idea. For so long, it wasn’t unprovable — we just couldn’t prove it yet. We just couldn’t put together the experimental data, and eventually, string theory assured us, it would pull a rabbit out of a hat and show us proof. 

That proof never came. That hope died. Supersymmetry enthusiasts and the occasional string theorist will try to argue otherwise, but the ideas haven’t produced results, and as more and more things get ruled out in experiments at the Large Hadron Collider, it seems like that horizon was a mirage this whole time.