The Strange Shape that Could Replace Space-Time --- Maybe

Scientific magazines and websites have been raising quite the hubbub about the Amplituhedron, a geometric structure that can be used to simplify calculations in particle physics. They claim that its existence means “space-time is doomed,” or some other nonsense along those lines. Today I will (try to) explain what all this is about.

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#science #sciencenews #physics #spacetime

[krogoratalai]

As a mathematician, a new way of calculating something is not “just a new way of calculating something”, because most don’t realise how much work is actually needed to reframe a problem in a completely different and novel way, which actually practically improves calculations. This is at its core, what physics is about, generating models of reality that help prediction, you cannot do anything better then this, except expect them to magically unify all theories or solve the Riemann hypothesis.

[yeroca]

The shape might work as a nice pendant for that physics girl in our life. The inscription on the card would read, "The shape of this pendant mathematically describes the amplitude of our love in a way that makes it easier to calculate. You're welcome."

[RFC]

Representing the same thing in a different way is often key to understanding connections between things that didn't appear to be connected (ex., realising the connection between elliptic curves and modular forms was a fundamental step in proving Fermat's "last theorem"), which then leads to a deeper understanding of both, and / or allows overcoming some (previously thought to be) "impossible" calculations along the way.

But it's hard to use "let's just represent this whole thing in a completely different way" as an argument to get a juicy grant or convince anyone to build a bigger particle accelerator. 🤑

[Votrae]

"You can express them as a polygon in a higher dimension of space"

I assure you I cannot do that. Awesome topic today!!

[bamber]

I’m the absence of headline-worthy developments in fundamental physics, popular science media are giving us headlines about mathematics. There’s nothing wrong with that. However, they then dress up the mathematics headlines to make us *think* they’re about physics. Sadly this is a reflection of most media headlines these days: they’re just hype with little at their core. This has been happening in biomedical sciences for a long time; I suppose it was inevitable in physics.🙁 Thanks, Sabine, for keeping a cool head and distinguishing between maths and physics.

[CatholicSatan]

Indeed, the Wiki page on Amplituhedron itself states: "While amplituhedron theory provides an underlying geometric model, _the geometrical space is not physical spacetime."_ You'd have thought those publications might have done a little reading beforehand...

[btmillack]

My understanding of those Amplituhedrons is as follows: The Feynman diagrams and the integrals come from the attempt to solve the equation by perturbation theory. Now the problem is that the single integrals give infinity, a somewhat unwanted result. We deal with them by renormalization, a way to subtract infinity from infinity to gain a useful result.
But nature says that the result should be finite so the problem might stem from the fact, that we calculate it wrongly. So lumping the integrals together in a way which does not give infinity might be a smart way to do the calculation.
I have to admit that I did not understand the Amplituhedron ansatz so I cannot say whether this hope really is the smart way we need to find.

[aholland]

Sabine makes my learning about science a little bit less annoying, so I think she's onto something! 🙂

[SvenDTL-jv]

Youtube is full of quacks passing themselves off as Doctors, yet you Dr Sabine are a real Doctor and seldom use the title you have earnt. The thing I like about your content is that you refuse to pander to any one particular side; you can go with the establishment or against it depending on your good judgement and understanding of the FACTS. You absorb, understand and then present these facts to us laymans and you do it with objectivity and good humour. Your content is trustworthy, informative and entertaining. It is such a rare thing to see these days. Thank you :)

[pathbound]

Thanks for what you do Sabine. I struggled in school as a kid mostly because I was bored. I am never bored listening to these little lectures and appreciate your humor.

[rangjungyeshe]

Sabine - as a former science writer in the UK, I agree there's not much happening (one of the reasons for I'm "former"). But one of the developments I have found intriguing is Cohl Furey's work on octonions and the Standard Model. She and a colleague have just published a preprint on ArXiv about a very recent and intriguing development concerning symmetries in the SM. I'd love to hear your take on it. Thanks.

[ayoCC]

Efficiency gains are very good, much more usable than revealing a new truth that has no practical usage

[boognewsnetwork]

"Space and Time are fine, they just ask that you respect their privacy." - Sabine
This is why you are among my favorite communicators. I could watch you and Sir Roger Pembrose almost continuously.

[markdowning]

Space-time doomed? That would be bad news for Matt O'Dowd. 😮

[aaronjennings]

The amplituhedron is closely related to twistor string theory, which is a variant of string theory. The twistor string theory provides a framework for understanding the scattering amplitudes in terms of twistor diagrams, which are analogous to Feynman diagrams but based on the geometric language of twistors. The amplituhedron emerges from the positive Grassmannian, a space that is central to twistor string theory...
So...
Huh.
I promise I have no idea what that means

[johnblakeH]

It says something about both comedians and physicists that one of the funniest people on YouTube is a physicist. You make physics and math(s) (yes, I'm from the US, lol) so much more interesting than any of my professors ever did, Sabine.

[ivaylovasilev]

Interesting, never heard a about the Amplituhedron, looks logical, hope it works

[krraai]

that visualisation of the amplituhedron at 2:30 an 4min looks like my migraine auras used to. i am so thankful that i have grown out of those. but the memory is still vivid and make me theorise that amplituhedrons were to blame all that time.

[ShannonNunn-sf]

He is talking about the locality of attractor fields that derive from mathematic equations, not locality of space time or using it to replace models. Weaving them together to understand the underlying principles that are causing them to congregate and orchestrate as they do.

[Taomantom]

While very flew so high over my head I never heard the wings flapping.