Jump to content
The Corroboree
nabraxas

Physicists propose method to determine if the universe is a simulation

Recommended Posts

Back in 2003, Oxford professor Nick Bostrom suggested that we may be living in a computer simulation. In his paper, Bostrom offered very little science to support his hypothesis — though he did calculate the computational requirements needed to pull of such a feat. And indeed, a philosophical claim is one thing, actually proving it is quite another. But now, a team of physicists say proof might be possible, and that it's a matter of finding a cosmological signature that would serve as the proverbial Red Pill from the Matrix. And they think they know what it is.

According to Silas Beane and his team at the University of Bonn in Germany, a simulation of the universe should still have constraints, no matter how powerful. These limitations, they argue, would be observed by the people within the simulation as a kind of constraint on physical processes.

Full sizemedium.png

So, how could we ever hope to identify these constraints? Easy: We just need build our own simulation of the universe and find out. And in fact, this is fairly close to what the physicists are actually trying to do. To that end, they've created an ultra-small version of the universe that's down to the femto-scale (which is even smaller than the nano-scale).

And to help isolate the sought-after signature, the physicists are simulating quantum chromodynamics (QCD), which is the fundamental force in nature that gives rise to the strong nuclear force among protons and neutrons, and to nuclei and their interactions. To replace the space-time continuum, they are computing tiny, tightly spaced cubic "lattices." They call this "lattice gauge theory" and it is subsequently providing new insights into the nature of matter itself.

Interestingly, the researchers consider their simulation to be a forerunner to more powerful versions in which molecules, cells, and even humans themselves might someday be generated. But for now, they're interested in creating accurate models of cosmological processes — and finding out which ones might represent hard limits for simulations.

To that end, they have investigated the Greisen–Zatsepin–Kuzmin limit (or GZK cut-off) as a candidate — a cut-off in the spectrum of high energy particles. The GZK cut-off is particularly promising because it behaves quite interestingly within the QCD model.

According to the Physics arXiv blog, this cut-off is well known and comes about when high energy particles interact with the cosmic microwave background, thus losing energy as they travel long distances. The researchers have calculated that the lattice spacing imposes some additional features on the spectrum, namely that the angular distribution of the highest energy components should exhibit cubic symmetry in the rest of the lattice (causing it to deviate significantly from isotropy).

"In other words," write the arXiv bloggers, "the cosmic rays would travel preferentially along the axes of the lattice, so we wouldn't see them equally in all directions."

And that would be the kind of reveal the physicists are looking for — an indication that there is indeed a man hiding behind the curtain.

And what's particularly fascinating about this is that we can make this measurement now with our current level of technology. As the researchers point out, finding this effect would be the same as 'seeing' the orientation of the lattice on which our own universe is simulated.

That said, the researchers caution that future computer models may utilize completely different paradigms, ones that are outside of our comprehension. Moreover, this will only work if the lattice cut-off remains consistent with what we see in nature.

At any rate, it's a remarkable suggestion — one that could serve as an important forerunner to further research and insights into this fasinating possibility.

The entire study can be found at Physics arXiv.

http://io9.com/59505...uter-simulation

  • Like 3

Share this post


Link to post
Share on other sites

600px-hubbleultradeepfieldwithscalecomparison.jpg

(Phys.org)—A common theme of science fiction movies and books is the idea that we're all living in a simulated universe—that nothing is actually real. This is no trivial pursuit: some of the greatest minds in history, from Plato, to Descartes, have pondered the possibility. Though, none were able to offer proof that such an idea is even possible. Now, a team of physicists working at the University of Bonn have come up with a possible means for providing us with the evidence we are looking for; namely, a measurable way to show that our universe is indeed simulated. They have written a paper describing their idea and have uploaded it to the preprint server arXiv.

The team's idea is based on work being done by other scientists who are actively engaged in trying to create simulations of our universe, at least as we understand it. Thus far, such work has shown that to create a simulation of reality, there has to be a three dimensional framework to represent real world objects and processes. With computerized simulations, it's necessary to create a lattice to account for the distances between virtual objects and to simulate the progression of time. The German team suggests such a lattice could be created based on quantum chromodynamics—theories that describe the nuclear forces that bind subatomic particles.

To find evidence that we exist in a simulated world would mean discovering the existence of an underlying lattice construct by finding its end points or edges. In a simulated universe a lattice would, by its nature, impose a limit on the amount of energy that could be represented by energy particles. This means that if our universe is indeed simulated, there ought to be a means of finding that limit. In the observable universe there is a way to measure the energy of quantum particles and to calculate their cutoff point as energy is dispersed due to interactions with microwaves and it could be calculated using current technology. Calculating the cutoff, the researchers suggest, could give credence to the idea that the universe is actually a simulation. Of course, any conclusions resulting from such work would be limited by the possibility that everything we think we understand about quantum chromodynamics, or simulations for that matter, could be flawed.

More information: Constraints on the Universe as a Numerical Simulation, arXiv:1210.1847 [hep-ph] arxiv.org/abs/1210.1847

Abstract

Observable consequences of the hypothesis that the observed universe is a numerical simulation performed on a cubic space-time lattice or grid are explored. The simulation scenario is first motivated by extrapolating current trends in computational resource requirements for lattice QCD into the future. Using the historical development of lattice gauge theory technology as a guide, we assume that our universe is an early numerical simulation with unimproved Wilson fermion discretization and investigate potentially-observable consequences. Among the observables that are considered are the muon g-2 and the current differences between determinations of alpha, but the most stringent bound on the inverse lattice spacing of the universe, b^(-1) >~ 10^(11) GeV, is derived from the high-energy cut off of the cosmic ray spectrum. The numerical simulation scenario could reveal itself in the distributions of the highest energy cosmic rays exhibiting a degree of rotational symmetry breaking that reflects the structure of the underlying lattice.

 

http://phys.org/news...simulation.html

Edited by qualia
  • Like 1

Share this post


Link to post
Share on other sites

Wow, that sounds cool. I think another interesting question though is would we really want to know about it if it was?

Share this post


Link to post
Share on other sites

or does it change our lived reality if it is?

or does it matter?

Share this post


Link to post
Share on other sites

My initial qualm is that I think it's over-sufficient to specify things at a small-scale, with a lattice. That we're brashly applying our concept of linearly-indepedent dimensions without questioning the appropriateness for it at small scales. If this is the case, if reality is "specified" with less than a lattice, then we won't find consistent evidence of one.

This idea is rooted in fractal geometry, and binary trees. All finite-dimensional fractals can be contained in a standard, orthogonal, finite-dimensional integer space (2D, 3D, 4D, 2000D, 1,000,000D, just the ceil() of the fractal dimension etc). In a concrete example, a fractal with dimension 1.618 (golden ratio, depicted below), can be contained in 2 dimensions (as it is in this image). But all of 2D cannot be contained within this fractal. A mapping can be made, but I think that it then contains non-unique mappings (would need to research more to be sure) - kind of like how a sine wave can depict 2D circular motion, but also a helical 3D trajectory and we can't be sure from only looking at the sine wave which one it represents (could be both).

Phi_glito.png

http://en.wikipedia....dorff_dimension

Basically the idea is that there's no point encoding "illegal" places within the fractal, and thus they are implicitly unable to ever be represented. If this is true for reality; that "illegal" places/events can never be "coded", then we might not find evidence of a lattice, which theoretically allows "illegal" things/events to be coded. This idea is related to http://en.wikipedia....wiki/Anisotropy which is being tested to see if our universe exists inside of a black hole. :P

I'm not entirely sure on the ramifications of my speculation, but it would definitely be something to do with non-unique mappings. In terms of experimental results, I'm not sure.

Secondly, I couldn't care less if we were living inside a simulation. I'd like to know for curiosity's sake, but it wouldn't mean the end of anything for me. Maybe just to try and get in contact with this potentially higher-being. I think the assumption is that a simulation has to be run by someone, which now that I think about it, might not necessarily be true. Simulations might spontaneously exist.

Edited by CβL

Share this post


Link to post
Share on other sites

any one heard of the hologram theory

Share this post


Link to post
Share on other sites

Religion would love it if the universe showed traits of being a simulation.

It opens a whole can of wormholes...

  • Like 1

Share this post


Link to post
Share on other sites

I thought Cantor showed that there exists a map between any n-dimensional structure and any n-1 dimensional structure. eg. the infinity of 3 dimensions can be mapped onto the infinity of 2 dimensions, as both share the same transfinite cardinality.

Thus there is no reason why an n-dimensional space cannot be mapped onto a 0-dimensional space (a point) in theory. however, in practise, it may be a lot harder to work backwards than forwards, and it becomes a question of the utility of the complexity that results from the mapping.

Share this post


Link to post
Share on other sites

Big fan of Bostrom he explains the topic on this video series What we still don't know. Are we real ?

I reanlly enjoy the way he explains, narrates the story the way he speaks the topic

 

Edit: spelling mistakes. You just can't post a smart video with silly spelling mistakes

Edited by 8145

Share this post


Link to post
Share on other sites

Nick Bostrom argues this topic quite well on this video series What we still don't know. Are we real ?

I really enjoy the way he explains it

 

Share this post


Link to post
Share on other sites

Thanks for that tip-off Thelema. I will have a lot of looking into this to do. I get the feeling that using that particular mapping - might have something to do with hidden variable theory. Or something. :P

While I did know about cardinality in general, I didn't know that the set of reals in higher dimensions could be mapped to the set of reals in a lower dimension. That the universe is coded in reals is probably also precluded by the quantization of energy. So in that sense the universe might be countable, so that theorem might not apply. :wacko:

Edited by CβL

Share this post


Link to post
Share on other sites

Wow there's gotta be something more that this plane of existence....

Share this post


Link to post
Share on other sites
or does it change our lived reality if it is?

or does it matter?

it depends on what the simulation is being run for.

for instance if it was a simulation ov "what happens when a low level civilization ov finite resources is attacked by a zombie making virus from space"

then it would matter.

also if the simulation has reached it's end, would the beings that created it turn it off (so to speak) or allow it to keep running?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×