HomeLatest ThreadsGreatest ThreadsForums & GroupsMy SubscriptionsMy Posts
DU Home » Latest Threads » Forums & Groups » Topics » Science » Science (Group) » Where Do Space and Time C...
Introducing Discussionist: A new forum by the creators of DU

Mon Apr 16, 2012, 01:28 PM

Where Do Space and Time Come From? New Theory Offers Answers, If Only Physicists Can Figure It Out


By George Musser


SANTA BARBARA—”Maybe we’re just too dumb,” Nobel laureate physicist David Gross mused in a lecture at Caltech two weeks ago. When someone of his level wonders whether the unification of physics will always be beyond mortal minds, it gets you worried. Since his lecture, I’ve been learning about a theory that seems to confirm Gross’s worry. It is so ridiculously hard that it could be the subject of an Onion parody. But at the same time, I’ve been watching how physicists are trying to power through their intimidation, because the theory promises a new way of understanding what space and time really are, at a deep level.

The theory was put forward in the late 1980s by Russian physicists Mikhail Vasiliev and the late Efin Fradkin of the Lebedev Institute in Moscow, but is so mathematically complex and conceptually opaque that whenever someone brought it up, most theorists started talking about the weather, soccer, reality TV—anything but that theory. It became a subject of polite conversation only in the past couple of years, as math whizzes who take a peculiar pleasure in impossible problems dove in and showed that the theory is not impossible to grasp, merely almost impossible.

Inspired by their bravery, I’m going to take a crack at explaining this strange beast, synthesizing lectures I’ve attended by Steve Shenker of Stanford University, Andy Strominger of Harvard, and Juan Maldacena of the Institute for Advanced Study, as well as informal chats with Joe Polchinski of the Kavli Institute for Theoretical Physics and Joan Simón of the University of Edinburgh. I’m sure they’ll set me straight if I get something wrong, and I’ll edit this blog post to reflect comments I receive.

Vasiliev theory (for sake of a pithy name, physicists drop Fradkin’s name) takes to extremes the basic idea of modern physics: that the world around us consists of fields—the electrical and magnetic fields and a handful of others that represent the known forces of nature and types of matter. Vasiliev theory posits an infinite number of fields. They come in progressively more complicated varieties described by the quantum-mechanical property of spin.

more

http://blogs.scientificamerican.com/observations/2012/04/12/where-do-space-and-time-come-from-new-theory-offers-answers-if-only-physicists-can-figure-it-out/

16 replies, 2210 views

Reply to this thread

Back to top Alert abuse

Always highlight: 10 newest replies | Replies posted after I mark a forum
Replies to this discussion thread
Arrow 16 replies Author Time Post
Reply Where Do Space and Time Come From? New Theory Offers Answers, If Only Physicists Can Figure It Out (Original post)
n2doc Apr 2012 OP
Vincardog Apr 2012 #1
Odin2005 Apr 2012 #13
liberal N proud Apr 2012 #2
rurallib Apr 2012 #3
veganlush Apr 2012 #4
Odin2005 Apr 2012 #15
drokhole Apr 2012 #5
Enrique Apr 2012 #6
GeorgeGist Apr 2012 #7
tama Apr 2012 #8
HopeHoops Apr 2012 #9
Jim__ Apr 2012 #10
LineLineNew Reply b
tama Apr 2012 #11
Odin2005 Apr 2012 #16
RagAss Apr 2012 #12
Odin2005 Apr 2012 #14

Response to n2doc (Original post)

Mon Apr 16, 2012, 01:49 PM

1. I read all the words. I wish I understood 1/2 the meaning

Reply to this post

Back to top Alert abuse Link here Permalink


Response to Vincardog (Reply #1)

Tue Apr 17, 2012, 09:44 PM

13. I understood it just fine.

Reply to this post

Back to top Alert abuse Link here Permalink


Response to n2doc (Original post)

Mon Apr 16, 2012, 02:04 PM

2. Not worried about where it comes from but where did it all go?

As time passes us by!

Reply to this post

Back to top Alert abuse Link here Permalink


Response to n2doc (Original post)

Mon Apr 16, 2012, 02:05 PM

3. this is where creationism comes in handy

all you have to do is answer 'God" and you pass the course.
Thanks for a mindbender of an article.

Reply to this post

Back to top Alert abuse Link here Permalink


Response to n2doc (Original post)

Mon Apr 16, 2012, 02:33 PM

4. the what now?

?

Reply to this post

Back to top Alert abuse Link here Permalink


Response to veganlush (Reply #4)

Tue Apr 17, 2012, 09:48 PM

15. Repeat after me: anti-De Sitter Geometry.

Reply to this post

Back to top Alert abuse Link here Permalink


Response to n2doc (Original post)

Mon Apr 16, 2012, 03:20 PM

5. Reminds me of a quote from JBS Haldane...

(to paraphrase) "My own suspicion is that the universe is not only stranger than we think, but stranger than we can think."

Reply to this post

Back to top Alert abuse Link here Permalink


Response to n2doc (Original post)

Mon Apr 16, 2012, 03:52 PM

6. I once knew someone that understood this type of thing

Reply to this post

Back to top Alert abuse Link here Permalink


Response to n2doc (Original post)

Tue Apr 17, 2012, 05:08 AM

7. Nothingness is impossible ...

after that it gets complicated.

Reply to this post

Back to top Alert abuse Link here Permalink


Response to n2doc (Original post)

Tue Apr 17, 2012, 09:55 AM

8. Scalar fields again

 

with holographic principle or some form of it. Those seem to be the central themes of all promising GUT and TOE candidates these days, and IMO the most advanced and promising of such approaches is Matti Pitkänen's TGD. Spin fields identified with rational numbers sounds to my very limited comprehension like a limited case of Pitkänen's more general idea about rational numbers as common areas between p-adic and real areas, and then some of which I understand even less.

Reply to this post

Back to top Alert abuse Link here Permalink


Response to n2doc (Original post)

Tue Apr 17, 2012, 10:28 AM

9. The book of Genesis explains it all quite clearly.

 



Reply to this post

Back to top Alert abuse Link here Permalink


Response to n2doc (Original post)

Tue Apr 17, 2012, 03:09 PM

10. Is the article giving us 3 different options for the nature of the universe? Or 2 different options?

Or am I completely misunderstanding what it is saying?

The article talks about 2 different holograpic universes and then about our spacetime emerging from the primordial universe as higher spin symmetries broke.

One holographic universe, under an anti-de Sitter geometry (?), has a 3D spacetime reality with a 2 dimensional space and a 1 dimensional time where a 3rd (pseudo)space dimension emerges:

... Higher-spin fields promise to flesh out the holographic principle, which is a way to explain the origin of space and gravity. Suppose you have a hypothetical three-dimensional spacetime (two space dimensions, one time dimension) filled with particles that interact solely by a souped-up version of the strong nuclear force; there is no gravity. In such a setting, objects can behave in a very structured way. Objects of a given size can interact only with objects of comparable size, just as objects can interact only if they are spatially adjacent. Size plays exactly the same role as spatial position; you can think of size as a new dimension of space, materializing from particle interactions like a figure in a pop-up book. The original three-dimensional spacetime becomes the boundary of a four-dimensional spacetime, with the new dimension representing the distance from this boundary. Not only does a spatial dimension emerge, but so does the force of gravity. In the jargon, the strong nuclear force in 3-D spacetime (the boundary) is “dual” to gravity in 4-D spacetime (the bulk).


The other holographic universe, under a de Sitter universe, has a real 3D space dimensions lying in an infinite future and a 4th holographic dimension of time:

... In the real universe, dark energy has a positive density, for a de Sitter geometry or some approximation thereof. Extending the holographic principle to such a geometry is fraught. The boundary of 4-D de Sitter spacetime is a 3-D space lying in the infinite future. The emergent dimension in this case would not be of space but of time, which is hard even for theoretical physicists to wrap their minds around. But if they succeed in formulating a version of the holographic principle for a de Sitter geometry, it would not only apply to the real universe, but would also explain what time really is. A lack of understanding of time is at the root of almost every deep problem in fundamental physics today.


And then there is the emergence of our spacetime from the primordial universe:

... Matter and spacetime geometry are so thoroughly entwined that it becomes impossible to tease them apart, and our usual picture of matter as residing in spacetime becomes completely untenable. In the primordial universe, where Vasiliev theory reigned, the universe was an amorphous blob. As the higher-spin symmetries broke—for instance, as the higher harmonics of quantum strings become too costly to set into motion—spacetime emerged in its entirety.


Are these 3 different options? Or, if our universe emerged from a primordial amorphous blob, did it emerge into one of the holograpic universes described above - which one depending on the underlying geometry?

Reply to this post

Back to top Alert abuse Link here Permalink


Response to Jim__ (Reply #10)

Tue Apr 17, 2012, 04:02 PM

11. b

 

http://en.wikipedia.org/wiki/Holographic_principle
http://en.wikipedia.org/wiki/De_Sitter_universe

The 3D space time is as said, hypothetical, and I assume just for presentation purpose, as also Minkowski space is normally presented as 3D projection of two spacetime cones.

The application of holographic principle to real 4D spacetime needs a spatial boundary where the information theoretical and thermodynamic bekenstein boundary that "holography" seems to refer here, would be observable, and that is impossible with the infinite dimension of time. The hope or promise is that in n-dimensional de Sitter space the holographic principle could be formulated.

The primordial amorphous blob refers to "superposition" of the "supersymmetric" spin scalars that by some spontaneous symmetry break broke down to 4D-space time.

So to my understanding these are not 3 different options, but attempt to unify QM and Relativity at the more general levels of spin scalars and n-dimensional de Sitter spaces.

The question remains, does this model suffer from the same landscaping problem as string/M theories and predict a vast multitude of possible universes, or is it more limiting case of World of Classical Worlds.

Reply to this post

Back to top Alert abuse Link here Permalink


Response to tama (Reply #11)

Tue Apr 17, 2012, 09:51 PM

16. That's the impression I got, too.

Reply to this post

Back to top Alert abuse Link here Permalink


Response to n2doc (Original post)

Tue Apr 17, 2012, 06:36 PM

12. We create space and time. It is the process with which we perceive reality.

Disagree with me and you're a Teabagger !


Reply to this post

Back to top Alert abuse Link here Permalink


Response to n2doc (Original post)

Tue Apr 17, 2012, 09:46 PM

14. Holy cow!!!

Reply to this post

Back to top Alert abuse Link here Permalink

Reply to this thread