tag:blogger.com,1999:blog-22973357.post4642748306541632450..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: Story about LIGO noise resurfaces in New ScientistSabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger47125tag:blogger.com,1999:blog-22973357.post-73095039433064220722018-12-07T19:56:20.388-05:002018-12-07T19:56:20.388-05:00Sabine,
Forgive me for not clarifying and for mis...Sabine, <br />Forgive me for not clarifying and for misunderstanding your intention. Foreground contamination for both projects is an analogous measurement-limiting condition, but LIGO has better press, more specialized Bayesian statisticians and programmers who are NOT cosmologists, astrophysicists, or astronomers, and less public demand for objectivity and transparency. ...I hope aLISA can pullfulguriticshttps://www.blogger.com/profile/13737543426886909156noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-45002907520700129152018-12-02T03:53:41.356-05:002018-12-02T03:53:41.356-05:00fulguritics,
BICEP did not measure gravitational ...fulguritics,<br /><br />BICEP did not measure gravitational waves. As I said above, they did an indirect measurement (or tried to do one) by measuring CMB polarization. Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-36568030686176216622018-12-01T04:54:41.857-05:002018-12-01T04:54:41.857-05:00Dear Sabine, you wrote:
"The BICEP signal w...Dear Sabine, you wrote:<br /><br /> "The BICEP signal was contaminated by foreground from the Milky Way. The same problem does not exist for LIGO."<br /><br />Indeed it does, but LIGO-Virgo are expected to be less oblivious to foreground, which is clear as so many papers devoted to the failure and improvement of stochastic GW searches - due (mainly) to Schumann resonances - have been fulguriticshttps://www.blogger.com/profile/13737543426886909156noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-87632055618348175772018-11-12T10:47:30.167-05:002018-11-12T10:47:30.167-05:00Not mentioned so far: there’s a citizen science/on...Not mentioned so far: there’s a citizen science/online crowd study of LIGO glitches; it’s called Gravity Spy, and has been running for quite some time now. I find it odd that none of the papers etc relevant to this discussion even mention this research, let alone how it might - or might not - help evaluate claims and analyses.<br /><br />While I’m far from being a dab hand at Gravity Spy, I’d be JeanTatehttps://www.blogger.com/profile/08737430572613792118noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-29907217671592750232018-11-08T19:28:33.653-05:002018-11-08T19:28:33.653-05:00@ Lawrence Crowell,
...the emergence of a clean s...@ Lawrence Crowell,<br /><br /><i>...the emergence of a clean surface. A part of what makes this is that the atomic aspects of the mirror, such as silicon etc, are smaller than the wavelength of the light.</i><br /><br />Well yes, the wavelength of the laser is of order 10^-6, but even allowing, for the sake of argument, the proposition that the laser can drive the atomic structure at 10-^10 to abud raphttps://www.blogger.com/profile/06948881286545517324noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-29771521421970199762018-11-07T07:07:31.635-05:002018-11-07T07:07:31.635-05:00Scientists are humans, I've heard. And scienti...Scientists are humans, I've heard. And scientists who working with expensive, publicly funded equipment are under hard pressure to succeed. Not so?<br /><br />So why not handle like good established: a result is only then a definit result if it was experienced and reported by several independent workers or groups.<br /><br />Because the tools are very expensive, there can not be the weristdashttps://www.blogger.com/profile/04693023273675933748noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-21915781796990466332018-11-07T05:40:18.894-05:002018-11-07T05:40:18.894-05:00@ bud rap,
My comment about the Mossbauer effect ...@ bud rap,<br /><br />My comment about the Mossbauer effect is that there is a similar classical behavior that occurs. For this reason there is the emergence of a clean surface. A part of what makes this is that the atomic aspects of the mirror, such as silicon etc, are smaller than the wavelength of the light. Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-86893845668146074902018-11-06T10:25:46.821-05:002018-11-06T10:25:46.821-05:00@Lawrence Crowell, I appreciate your considered re...@Lawrence Crowell, I appreciate your considered response but I don't think it addresses the problem I raised. The question regards the nature of the mechanical system employed and whether or not it is capable of detecting a 10^-20 signal. The mirrors employed are not crystals. The Mossbauer effect is dependent on the crystal lattice.<br /><br />To state my objection in a slightly different bud raphttps://www.blogger.com/profile/06948881286545517324noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-32093291850466305932018-11-05T12:42:18.985-05:002018-11-05T12:42:18.985-05:00David,
It says in the caption below the figure ho...David,<br /><br />It says in the caption below the figure how the data has been processed. The issue isn't the data (and not the documented processing of the data either) the issue is the model that's being subtracted (where does it come from?) and that the quantity shown is not the quantity that's actually used to determine the significance. As I said, I have not heard the rumor thatSabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-27904979141021886732018-11-05T12:39:48.539-05:002018-11-05T12:39:48.539-05:00https://arxiv.org/abs/1602.03844
Maybe here?https://arxiv.org/abs/1602.03844<br /><br />Maybe here?PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-75988337111100536642018-11-05T12:16:04.756-05:002018-11-05T12:16:04.756-05:00"It's not the raw data that is shown. &qu..."It's not the raw data that is shown. "<br /><br />So do you know what it is? Is it an artist's impression (analogous to the one originally presented)? Is the quoted scale magnification real - I mean if so we are still talking about an extracted signal that is about 500 times less than the raw signal. Is the filter basically a low-pass filter, or something more elaborate? If theDavid Baileyhttps://www.blogger.com/profile/06172248428321078417noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-45216185899400046432018-11-05T12:06:41.915-05:002018-11-05T12:06:41.915-05:00The BICEP3/Keck effort is updated here.
http://bi...The BICEP3/Keck effort is updated here.<br /><br />http://bicepkeck.orgLawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-42615812569069607202018-11-05T06:11:37.146-05:002018-11-05T06:11:37.146-05:00pete,
As I mention in the last paragraph.pete,<br /><br />As I mention in the last paragraph.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-56807880586419451862018-11-05T05:35:47.934-05:002018-11-05T05:35:47.934-05:00I though additional gravitational waves have been ...I though additional gravitational waves have been detected by LIGO from Neutron Star mergers as well?Alanhttps://www.blogger.com/profile/00375734596064810061noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-39947964558611517962018-11-04T23:03:45.383-05:002018-11-04T23:03:45.383-05:00David,
It's not the raw data that is shown. T...David,<br /><br />It's not the raw data that is shown. The window-function has nothing to do with the glitches. A badly performed windowing will leave you with periodic residuals that look neither like a glitch nor a signal. Best,<br /><br />B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-66832655121293780892018-11-04T17:09:13.818-05:002018-11-04T17:09:13.818-05:00Good to hear, could you cite the BICEP3 paper?
Good to hear, could you cite the BICEP3 paper?<br />WRLhttps://www.blogger.com/profile/04323354407920835050noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-45026978268632627732018-11-04T13:11:09.075-05:002018-11-04T13:11:09.075-05:00I guess it appears I was wrong. I thought squeezin...I guess it appears I was wrong. I thought squeezing had been implemented with the upgrade or advances that were made a few years ago.Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-15618363929958975522018-11-04T13:10:55.630-05:002018-11-04T13:10:55.630-05:00The New Scientist article shows the raw data (red ...The New Scientist article shows the raw data (red line with no signal visually emerging from the noise) and the filtered data magnified by 100 (blue line). Even with this magnification, the blue signal is much smaller than the raw data.<br /><br />Even without knowing any of the details of the experiment, this gives me a very queasy feeling about this result. The NS article also explains that &David Baileyhttps://www.blogger.com/profile/06172248428321078417noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-71201526263158944372018-11-04T07:59:15.251-05:002018-11-04T07:59:15.251-05:00@Lawrence Crowell The Caltech LIGO R&D webpage...@Lawrence Crowell <a href="https://www.ligo.caltech.edu/mit/page/research-development" rel="nofollow">The Caltech LIGO R&D webpage</a> currently lists squeezed light as a possible future improvement to LIGO. It says that they have currently eliminated almost all other noise, so that using squeezed light is the most feasible way to improve detector resolution at this point. But it also says Peter Shorhttps://www.blogger.com/profile/13823970640202949073noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-45815328214276447512018-11-04T07:07:29.084-05:002018-11-04T07:07:29.084-05:00@ Peer, I am not able to find any reference to you...@ Peer, I am not able to find any reference to your statement the detections did not employ squeezed photon states. There is the reference below that states squeezed coherent states of light were employed in 2011.<br /><br />The LIGO Scientific Collaboration (2011). "A gravitational wave observatory operating beyond the quantum shot-noise limit". Nature Physics. <b>7</b> (12): 962. Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-85592948459185868572018-11-04T01:58:23.935-04:002018-11-04T01:58:23.935-04:00Typo: in here it should be from chapter 27.6.2 on...Typo: <a href="https://backreaction.blogspot.com/2018/11/story-about-ligo-noise-resurfaces-in.html?showComment=1541236309231#c2121016183283890892" rel="nofollow">in here </a> it should be from chapter 27.6.2 on.Reimondhttps://www.blogger.com/profile/04669340425105889539noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-73038323867472814952018-11-03T19:47:01.242-04:002018-11-03T19:47:01.242-04:00@Lawrence Crowell LIGO did not used squeezed light...@Lawrence Crowell LIGO did not used squeezed light in the experimental run that made the detections talked about here.fulishttps://www.blogger.com/profile/17357991149861003460noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-81890341916418281942018-11-03T10:44:52.090-04:002018-11-03T10:44:52.090-04:00@bud rap
Kio Thorn has recorded a whole online cou...@bud rap<br />Kio Thorn has recorded a whole online course on how the geavital wave detector works and how they reached this sensitivity. If you relly want to understand this, go to:<br />Lec 1 - Phys 237: Gravitational Waves with Kip Thorne<br />https://youtube.com/watch?v=Afq4b1HZcIc<br />Rob van Son (Not a physicist, just an amateur)https://www.blogger.com/profile/12611755507524401026noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-6323596421248453662018-11-03T10:44:23.510-04:002018-11-03T10:44:23.510-04:00The Danish group's paper "On the time lag...The Danish group's paper "On the time lags of the LIGO signals" says: "With special focus on GW150914, we report correlations in the detector noise ... the other two events, GW151226 and GW170104, exhibits similar behavior." <br /><br />Dear Sabine (or dear readers): Do you know if there is similar correlation found in detector noise for GW170817, the neutron star event?Ashish Sirohihttps://www.blogger.com/profile/01191841016592807961noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-72409368235102498042018-11-03T07:29:13.412-04:002018-11-03T07:29:13.412-04:00@ bud rap,
This problem you appear to be alluding...@ bud rap,<br /><br />This problem you appear to be alluding to is removed by squeezing the QED vacuum of the laser photons. With quantum mechanics we have the ΔpΔx ≥ ħ/2. This would appear to make measurements LIGO performs impossible, and the Δx would make the position of the mirror impossible to pin down. However, this is the uncertainty principle at quadrature. The squeezed state operator is Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.com