
Signatures of extra dimensions in gravitational waves - robin_reala
https://arxiv.org/abs/1704.07392
======
chairmanwow
I originally thought this paper presented evidence for extra dimensions
discovered in gravitational wave readings.

This is certainly not the case, as this paper presents two potential effects
from higher dimensional gravity waves and proposes methods to detect them.

Namely, we would need an equivalent to LIGO that features detection arms in
all three axes rather than just X and Z. The second predicted effect requires
a GWave detector that is several orders of magnitude more sensitive than LIGO.

~~~
TheRealDunkirk
> I originally thought this paper presented evidence for extra dimensions
> discovered in gravitational wave readings.

And you've perfectly illustrated the current problem with science reporting.
It's hard to keep people interested in ongoing discovery when 1) the link
doesn't accurately represent the paper's thesis, and 2) the paper is so obtuse
as to require a specialized degree to understand.

Whatever your qualifications, _your_ comment provided the context to
understand what was being asserted. You are the sort of person who should be
writing articles on scientific papers.

~~~
Steuard
This isn't a "science reporting" site: arXiv.org is providing the actual
scientific article. The paper is _supposed_ to require a specialized degree to
understand: that's the intended audience of the vast majority of content on
arXiv.org. (And for regular users of the site, it's immediately clear that no
paper categorized as "hep-th: High Energy Physics - Theory" would be
announcing actual observational results.)

Aside: The authors of this article seem to have submitted a revised version a
couple of weeks ago; sometimes (but not always) that coincides with either
journal submission or responding to reviewer comments. There's no indication
here yet of what its current stage in the peer review process is.

Edit: I see from later comments here that the target of this link may have
been changed to arXiv.org after its original submission. If the earlier link
was paywalled as someone said, that suggests that this result _has_ been
formally published somewhere. (I'm a little surprised that the authors didn't
note that on the arXiv page once it happened.) So maybe the earlier context
made the purely theoretical nature of the paper less clear.

~~~
homarp
Journal of Cosmology and Astroparticle Physics
[https://doi.org/10.1088/1475-7516/2017/06/048](https://doi.org/10.1088/1475-7516/2017/06/048)

Received 8 May 2017

Accepted 13 June 2017

Published 23 June 2017

~~~
pvitz
I am astonished how quickly it was reviewed and published. Is this common for
journals on cosmology? It has been some years but I remember that submissions
to e.g. Phys.Rev.E could take a long time till they would be published.

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dest
At the end of the article (!): Our warmest thanks go to the Deutsche Bahn AG
for providing us with comfortable office space in their conveniently delayed
trains.

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mirimir
tl;dr - There are two expected signatures: "breathing mode" (maybe like
p-waves?) and high-frequency components. Seeing the first would require at
least three independent detectors sensitive to polarization. Seeing the second
would require at least several orders of magnitude increase in frequency
response.

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paulpauper
mind-blowing how complicated these equations are

each symbol with a superscript or subscript represents part of a system of
differential equations

each individual equation is a function of 10 or more variables

wish I understood it better

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exabrial
I've had this crazy thought for awhile that the physical dimensions we see are
the three dimensions of gravity, and that there are a similar number of
dimensions for time.

~~~
logfromblammo
So have I.

I have an "everything moves at c" hypothesis, wherein everything has an
inertia/velocity vector with 3 spatial (squares to 1) components and 3
temporal (squares to -1) components. The magnitude of every vector is c.

We see three spatial dimensions, because the portion of our vector from the
temporal components is almost c. Our inertia makes it very difficult to change
our directional vector through the temporal dimensions, because we are almost
at rest in the spatial dimensions. So we see time as a single dimension,
because it is practically impossible for us to change the temporal-only
components of our vector. Similarly, for an electron, when the spatial
component of the vector is nearly c, it would perceive space as one
dimensional, and would require less energy to change direction in the temporal
dimensions. This results in spatial behavior that requires the use of
probabilities.

We perceive up-down, left-right, front-back, and before-after. Someone moving
at near-c through space might perceive to-fro, entropy-order, likely-unlikely,
because-causes, or similarly incomprehensible-to-us dimensions.

This hypothesis is all thanks to the Back to the Future movies. Why does the
DeLorean have to go 88 mph? Because the Doc could only generate 1.21 GW, and
in order for that much energy to change your direction through time, you have
to be moving at 88 mph. If you were going 120 mph, you would need less energy,
but in 1985, 88 was about as much as you can expect from a commodity
automobile. It also received significant contribution from quaternion-based
mathematics, which is completely symmetric with respect to dimensional
signatures of (3,1) and (1,3).

~~~
trhway
>but in 1985, 88 was about as much as you can expect from a commodity
automobile.

you probably missed all the history and context of DeLorean :) (In all other
respects, your comment sounds interesting).

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jensenbox
Somewhere in my ancestral line I have a relative that can read and write the
sort of math that is in this paper.

I have given myself the OK that I will never be able to do a gosh darn thing
even close to what I just saw.

I just hope that somewhere in my life I am able to do something that is just
as awe inspiring to someone else.

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k__
I have no idea about physics, but I thought the holographic principle said
that it was the other way around?

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olleromam91
What if dark matter is just mass that is moving faster than light?

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nategri
Calling all HN physics cranks.

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vardump
Same (?) paper (possibly a slightly different version), but without paywall:
[https://arxiv.org/abs/1704.07392](https://arxiv.org/abs/1704.07392)

~~~
mirimir
Yes, same paper.

That's the "ArXiv ePrint" link in the paper that I get via Sci-Hub.

~~~
JadeNB
It is also linked at the IOP page itself.

