## Physicists Discover Geometry Underlying Particle Physics 600

Posted
by
Soulskill

from the amplituhedron-is-the-word-of-the-day dept.

from the amplituhedron-is-the-word-of-the-day dept.

New submitter Lee_Dailey sends this news from Quanta Magazine:

*"Physicists have discovered a jewel-like geometric object that dramatically simplifies calculations of particle interactions and challenges the notion that space and time are fundamental components of reality. 'This is completely new and very much simpler than anything that has been done before,' said Andrew Hodges, a mathematical physicist at Oxford University who has been following the work. The revelation that particle interactions, the most basic events in nature, may be consequences of geometry significantly advances a decades-long effort to reformulate quantum field theory, the body of laws describing elementary particles and their interactions. Interactions that were previously calculated with mathematical formulas thousands of terms long can now be described by computing the volume of the corresponding jewel-like "amplituhedron," which yields an equivalent one-term expression."*
## hmmm.... (Score:4, Interesting)

## Hold up. (Score:5, Interesting)

Guys, we've been down this road about a million times in physics. Just because a mathematical model simplifies certain calculations, does not mean that the actual underlying physical geometry matches the theoretical model. Mathematicians have been adding extra dimensions to equations and finding they simplify things for years. It doesn't mean we live in a 27 dimension manifold. All direct observations to date point to a 3D universe.

## Re:Hold up. (Score:5, Interesting)

Doesn't mean we don't. ;-)

Ummm ... hang on a second. Won't any direct observation we make as 3D critters point to a 3D universe? Isn't that sort of inherent to us being only able to perceive 3D?

I'm not sure how we'd do any direct observations in any other dimensions. (Honestly, not a flame, I'm genuinely puzzled by how we could see anything else and every now and then something like this hurts my head)

## Re:Hold up. (Score:5, Interesting)

Then again, mathematicians tend to be a bit crazy. I remember reading one bio-mathematics person determining that bees do their little waggle dances in nine dimensions projected onto two, and I thought she was insane.

## Oblig (Score:5, Interesting)

## Wrong on all points (Score:3, Interesting)

Modern physicists have studied all of that, and more.

In fact the physicists I know are also the best read on the classics and have a tremendous breadth of knowledge about many subjects other than physics. Perhaps you should actually get to know them.

And incidentally, most Physicists don't use Cartesian corrdinats. Physicists use whatever coordinate system they need to use depending on the geometry, and the real world is far from Euclidian.

## Breakthrough or bullshit? (Score:4, Interesting)

This is either a major breakthrough or utter bullshit. It's too early to tell which. If it's real, it's a Nobel Prize in physics.

The publisher, the Simmons Foundation, is a project of a rich weirdo from Texas.

## Re:Hold up. (Score:5, Interesting)

Dude, seriously, WTF?

I said I have no idea what this even means, and you are suddenly talking theology. So, I don't know one thing and therefore something else exists or doesn't exist? What is this, quantum bullshit?

Well, no shit. Did I make any assertions we're creating universes anywhere in my post? I asked how we could see anything outside of 3 dimensions through direct observation.

Again I say, WTF are you on about? Your entire most makes no sense to me.

## Re:Hold up. (Score:4, Interesting)

You know how neutrinos have this tendency to change flavors as they pass through time (i.e. neutrino oscillation)? One nifty way of viewing it is that they're 4D objects simply with a spin in the fourth dimension. If you're into the physics, you'll note the same sort of calculations are used in the Pontecorvo–Maki–Nakagawa–Sakata matrix as are used by game engines when calculating the 2D representations of 3D virtual objects: You just then need to do basic matrix transformations to derive the result.

## Re:hmmm.... (Score:5, Interesting)

This isn't a particle so much as methodology

The important bit here is why? Why does this methodology work so well. Is it because that deep down on a very fundamental level this "Geometry" is hard coded in the way the universe works? If so. What does this tell us about how things really work?

## Re:42 (Score:5, Interesting)

Are you a singularity nut or just a misguided computationalist?

A singularity nut. Your brain is a machine. It can be understood, decompiled, analyzed, improved and reimplemented. You're already an AI running on appropriate (and at some point in future becoming outdated) hardware.

Unless you believe in souls. Do you believe in souls?

## space & time as emergent properties (Score:5, Interesting)

Warning: IANAP. But with some axioms, it is possible to reach the same conclusion.

Imagine a simple experiment with an electron source and a detector. An electron is emitted in the direction of a detector. The experiment is set up such that while travelling towards the detector, the electron does not interact. More precisely, in between the emitter and the detector, the electron does not exchange any energy. Then, the electron hits the detector and becomes detected (interaction two).

Has the electron physically travelled in the space between the electron source and the detector? May it be assumed that in between the interaction with the emitter and its subsequent interaction with the detector the electron is physically present?

Obviously, it is impossible to establish that the electron is present between the emitter and the detector without actually interacting with the electron. It is therefore herewith observed that any assumptions about physical presence of the electron in between the source and the detector can not be experimentally verified. More generally, it is observed that the assumption of physical presence of any elementary particle in between two interactions can not be falsified.

Equally impossible to falsify is the assumption that in between the emitter and the detector, the electron in the experiment was

notphysically present. This assumption implies that (in the reference frame of the observer) the electron disappeared at the emitter and reappeared at the detector, and did not take up any physical space at any time in between. In between interactions, the representation of the electron disappeared and became unobservable. For as far as an observer can tell, the electron disappeared from the universe completely in between interactions.Since obviously, properties about the electron are preserved in between interactions, the electron must still somehow being represented – i.e., the representation of the electron has clearly not disappeared from the universe.

The notion “observable universe” is therefore being introduced to make the distinction between interactions which can be observed, and the herewith theorized part of the universe that is apparently capable of at least holding a representation of an elementary particle and which can

notbe observed.Observable universe: The part of the universe in which an interaction manifests itself.Let us formulate the following two axioms:

Axiom 1: An interaction is instantaneous, i.e., it lasts for an infinitely small amount of time.Axiom 2: An elementary particle only exists in the observable universe at the moment of its interaction.Notice that axiom 1 and 2 are unfalsifiable. Consider the reverse of axiom 2:

Reverse of Axiom 2: An elementary particle physically exists in the observable universe in the time that passes (in the reference frame of an observer) between two interactions.This axiom is equally unfalsifiable, since physical presence of an elementary particle can only be proven by interacting with it. The reverse of axiom 1, which would postulate that an interaction lasts a non-zero amount of time, is equally unfalsifiable.

Elementary particles have no internal structure and are considered point particles. In other words, an elementary particle does not take up any physical space. If we assume that everything in the observable universe consists of elementary particles, then it follows that all particles that exist in the universe do not take up any space. The aggregate volume of all elementary particles is zero.

Combined, axioms 1 and 2 state that in between two interactions, an elementary particle is not present in the observable universe. A particle only manifests itse

## Re:Hold up. (Score:5, Interesting)

Feynman diagrams are based on the idea that there is framework of time and space, more specifically basically the same time and space that we perceive in everyday life.

This new model apparently takes a simpler view of the problem by not caring about time and space. I suppose you could say that time and space could be viewed as emergent properties of this geometric object that they have come up with / discovered.

## Re:hmmm.... (Score:5, Interesting)

This isn't a particle so much as methodology

The important bit here is why? Why does this methodology work so well. Is it because that deep down on a very fundamental level this "Geometry" is hard coded in the way the universe works? If so. What does this tell us about how things really work?

That's a pretty good question. I've been wondering about that too, given the convergence between our definitions of entropy and Kolmogorov complexity, which describes how much information is encoded in a signal (also tied in with Shannon's law). It hits directly into the heart of the question: what is information and how does it relate to reality? At a basic level, our universe may be comprised of "information", or rather: a signal on top of noise.

This new discovery seems to suggest that at the most basic level, particles can be described as a mathematical function on top of some sort of "white noise" as well. I wonder how long it will take to converge the two ideas. If ever.

In any case, exciting times are ahead for so-called computer scientists that deal with things like geometric algorithms. I predict a hot demand for top mathematicians in that field to arise very soon.

Anyway, exciting times to be a theoretical physicist! Everyone expecting breakthroughs coming from the LHC and the experimental boys and girls, and now suddenly, out of left field the theoretical physicists come back with a big right hook out of nowhere :)

## Re:Hold up. (Score:5, Interesting)

Check out Richard Feynman's lecture regarding space-time and his analogy of bugs on a sphere. If you tell them that the rule for making a square is to go N units in one direction, then turn 90 degrees and repeat until you complete the square, they would find that they cannot actually make a square. This leads them to conclude that there is "something wrong" with their space.

The point is that while the underlying nature of their universe as a sphere is unavailable to them because they cannot escape it to see the bigger picture, they can still infer that because Euclid's rules of geometry don't work there must be something going on that they can't see. Moreover, they should be able to guess that there is curvature - without knowing for sure - because of exactly how the rules break down.

This is essentially what people talk about when they refer to the difference between larger objects like clumps of atoms and smaller ones like electrons and quarks. For some reason our 3D (technically it's 4D according to Einstein) universe only behaves "normally" until we start measuring it at a small scale. Then we start seeing where our rules about the behavior of "observable" objects - i.e., the stuff we can perceive with our senses - break down and are replaced by the true nature of the subatomic universe. In other words, when we look at quarks do stuff, we can no longer make the square.

Constructs like the one described above are the result of us trying to get our little bug heads around the way in which our every day rules break down when really tiny things are involved. It's a way for the bugs to correct Euclid to account for the spherical nature of things.

## Re:42 (Score:4, Interesting)

The human concept of "a soul" is an emergent property of high order intelligence.

You know that the "emergent property" expression is technobabble, right?"

Emergent properties are phenomena which are a product of the characteristics of the set of entities which are interacting with each other and the structure of that interaction.

A water molecule doesn't have a snowflake hiding in it, nor does it have some quality of "snowflakeness".

Take a bunch of water molecules, have them interact with each other in the right environment, and you get snowflakes.

No technobabble needed.

## Re:Bejeweled... (Score:2, Interesting)

You're technobabble sucks.Your English sucks. When did you drop out, junior high? Get your GED, kid.

Oh, and BTW, A neutrino is an electrically neutral, weakly interacting elementary subatomic particle with half-integer spin. The neutrino (meaning "small neutral one" in Italian) is denoted by the Greek letter (nu). All evidence suggests that neutrinos have mass but that their mass is tiny even by the standards of subatomic particles. Their mass has never been measured accurately.

Tachyons are a bit of mental masurbation. They're hypothetical particles that can't exist within known physics that always go faster than light.

Neutrinos are real science, tachyons are technobabble. Just because you're either not smart or educated enough to understand someone who has actually gotten an education does not mean they're babbling, it means you're ignorant.

Here's a hint, kid -- if you don't understand a term, look it up. To not do so makes you not a nerd (and so does the phrase "you're technobabble sucks").

WTF has happened to slashdot? We never used to have ignorant comments like that, let alone have them modded up.

## Re:42 (Score:4, Interesting)

I'm working on my PhD in math now and writing my thesis on complex systems. I'm going to call bullshit on that. While a lot of people throw the term around very loosely, emergence is a well-defined, known mathematical property of complex systems. I wouldn't go so far to say that we completely understand it on a biological level, but we can definitely study the properties of emergence through constructing a purely mathematical, complex system. But I'm not going to deny that our consciousness isn't emergent behavior, either. Neural networks are a textbook example of a complex system, and maybe the system for neural networks has emergence properties. I don't know, I can't claim to know, but it seems to fit with the math and science. To say emergence is technobabble nonsense is just ignorant, when it's a well defined property in a field of mathematics.

## Re:42 (Score:3, Interesting)

However, the fact that actual proteins manage to do it in a microsecond or less suggests there's a very easy way we just aren't aware of yet.

Nature doesn't calculate like we do, it works like a quantum computer. Meaning, all the possible outcomes of the calculation (a step in the shaping of the protein) occur at the same time (each has a certain probability of occurring). So basically nature "computes" every possibility in parallel and then picks an outcome at random, weighted by probability.

Consider: it can be the case that the development of new mathematical tools works as a kind of Moore's Law for scientific research, making thing exponentially simpler with every step.

This would basically mean that P=NP (a statement that is not yet proven nor disproven in mathematics). It's possible, but that would be a much, much bigger discovery than what they announced now.

Basically what they found now is a special geometrical construct, in which they can plug the data of a number of particles, then they calculate certain volumes in the construct, and these give the probabilities of the interactions between the particles.

Before this, they had to calculate all the possible interactions between all the particles (Feynman diagrams), and then average all probabilities. The new method gives the same numbers with much less calculations. It's a bit like calculating air pressure by calculating the forces by each molecule separately, versus applying the ideal gas laws.

The new method will undoubtedly lead to new understandings about particle interactions, but the maths are not some magic formula that can accelerate any calculation.