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.
> 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.
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.
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.
> And you've perfectly illustrated the current problem with science reporting.
In this cases, this is the proposed title to the research article in the peer review journal. (Is this accepted yet?) So this is not a problem of a bad clickbait journalism.
My guess is that it's a good title for the people in the area, because they have enough context of the current research state to guess that it's a theoretical result and not an experimental result (and in case of doubt they can RTFA). So I suspect it's not malice (neither stupidity).
> the paper is so obtuse as to require a specialized degree to understand.
I have no degree in physics and I find the authors make a decent job giving several summaries (abstract, introduction, description of the work) that make clear that they propose hypotheticals that could be observed, not actual observerations.
> We discuss whether these two effects could be observed.
From my understanding as a layperson, using other LIGO style detectors to substitute the z-axis won’t work. You need to shoot laser pulses continuously and in sync into two axes from the same detector to be able to detect ripples in spacetime. The sensitivity of two non-connected detectors working together is not high enough. See [1] for how the detection works.
Given the size of the wavelength is multiples of the earth are they not able to sync up the section of the wave being measured and deduce further measurements from there?
You couldn't add 1 axis of another detector as a 3rd leg but having 3 measurements on 3 planes from 3 pairs of beams due to their positions on earth should. Each stations 2 axis measure 1 plane, and you build the 3 plane from the positions on the earths surface.
Wouldn't the relative velocities of the earths spin, orbit and the solar systems velocity from the gravity wave origin all make the above measurements... difficult. Or all things considered, the angular tiny velocity from the origin makes that irrelevant.
LIGO is an interferometer. Light is made to interfere with itself. You can't integrate results from other LIGOs to recover the Z dimension because you'd be missing the requisite opportunity to interfere light traveling across that arm with light from the others.
Other detectors around the surface of the globe will be oriented on different planes. The two we have now give error-rejection and, I suppose 1-D detection. Add another in Europe and one in Australia, do some trigonometry, and bob's your uncle, no?
OP said "a few". The paper says LIGO et al. are sensitive up to an order of 3 or 4; planned interferometers are targeted at lower ranges. The needed device needs to be sensitive to modes of at least order 12---but preferably order 21 & higher (to cover all theories). So, realistically, they're about 18 orders of magnitude off. Conservatively.
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.
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.
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.
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).
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.