tag:blogger.com,1999:blog-22973357.post8701002355900262697..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: Space may not be as immaterial as we thoughtSabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger41125tag:blogger.com,1999:blog-22973357.post-69780264800815781132017-12-12T00:37:38.183-05:002017-12-12T00:37:38.183-05:00Michael,
The Higgs field (background value) is om...Michael,<br /><br />The Higgs field (background value) is omnipresent. The rest of your comment doesn't make sense. Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-32599032953043528392017-12-11T15:30:58.622-05:002017-12-11T15:30:58.622-05:00Sabine, do you think that the Higgs field might tu...Sabine, do you think that the Higgs field might turn out to be omnipresent throughout space, connecting everything as a real explanation for gravity? Could we then throw out the metaphysics of the non-entity "spacetime?"Anonymoushttps://www.blogger.com/profile/14389375034282574803noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-84735355551405206292017-10-27T12:04:30.210-04:002017-10-27T12:04:30.210-04:00Guillermo,
It seems this is a revival of this ide...Guillermo,<br /><br />It seems this is a revival of <a href="http://backreaction.blogspot.de/2012/04/can-we-probe-planck-scale-physics-with.html" rel="nofollow">this idea.</a> It was wrong in 2012, it's still wrong. Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-42978437953460351172017-10-27T11:25:43.224-04:002017-10-27T11:25:43.224-04:00Sabine, perhaps you already know about this experi...Sabine, perhaps you already know about this experiment, but in case you don't, I've already found this article in phys.org:<br /><br />https://phys.org/news/2017-10-physicists-quantum-gravity-current-technology.html<br /><br />From some post of yours I've been reading in the last months, I infere that you don't like pop science divulgation that much, but in my humble opinion Guillermohttps://www.blogger.com/profile/13983291874539573971noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-81965589640886329002017-10-26T10:42:18.251-04:002017-10-26T10:42:18.251-04:00Yes, except that just like you said its natural co...Yes, except that just like you said its natural computation process in some form underlying all scale. And exactly because of this, thinking parallel about black holes and quantum computation is so much interest, just as ads/cftSheeverhttps://www.blogger.com/profile/12931916936543585461noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-40336159608567864142017-10-26T08:15:30.891-04:002017-10-26T08:15:30.891-04:00[The underlying spacetime for analog gravity fluid...<i>[The underlying spacetime for analog gravity fluid models is] Lorentzian and you can treat the fluid both relativistsically and in the non-relativistic limit.</i><br /><br />Okay, so in that case I wouldn't say the fluid IS spacetime, I would say the underlying Lorentzian spacetime - within which the fluid exists and moves - is spacetime, and the fluid is, well, a fluid. I suppose one Amoshttps://www.blogger.com/profile/00595591283398023248noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-14692829878852677802017-10-25T03:17:51.851-04:002017-10-25T03:17:51.851-04:00Amos
There are several ways you can attack the pr...Amos<br /><br />There are several ways you can attack the problem <br />As an example check up Xiao-Gang Wen on spin liquid. He is working on it over decade, and his theory actually uv complete. <br /><br />Second, you can also study from another direction such us ising model XY universality, magnetic orders etc and gravitational anomalies (see graphene) the superfluid analogue it's just one Sheeverhttps://www.blogger.com/profile/12931916936543585461noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-82253319278277042232017-10-25T01:39:35.396-04:002017-10-25T01:39:35.396-04:00Amos, the analog gravity models are based on stand...Amos, the analog gravity models are based on standard condensed matter theory. One can, of course, also consider relativistic theories of condensed matter theory, but, given that the characteristic speed in these models is the speed of sound, much smaller than the speed of light, this is usually not done. So, the underlying spacetime model is Newtonian absolute space and absolute time. <br /><brIlja Schmelzerhttps://www.blogger.com/profile/05344206562643658764noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-51306329744310917032017-10-24T23:37:47.252-04:002017-10-24T23:37:47.252-04:00And yes, you can define a distance measure from th...And yes, you can define a distance measure from the network. That isn't the challenge. The challenge is to get the connectivity of the network to resemble a locally flat 3(+1) dimensional space-time. That's highly non-trivial & not any network will do. Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-53275293771696105342017-10-24T23:35:55.081-04:002017-10-24T23:35:55.081-04:00Amos,
It's Lorentzian and you can treat the f...Amos,<br /><br />It's Lorentzian and you can treat the fluid both relativistsically and in the non-relativistic limit. Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-4318726869944648872017-10-24T15:56:51.907-04:002017-10-24T15:56:51.907-04:00She mentioned networking if you were reading above...<i>She mentioned networking if you were reading above.</i><br /><br />Does mentioning networking really answer the question? I believe (correct me if I'm wrong) the analog gravity models mentioned in the post are based on modeling the fluid, not on an abstract network, but in some underlying spacetime. So, for this case, my question was: Is the underlying spacetime for analog gravity fluidAmoshttps://www.blogger.com/profile/00595591283398023248noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-64919689801360881462017-10-23T11:19:42.696-04:002017-10-23T11:19:42.696-04:00Amos
She mentioned networking if you were reading...Amos<br /><br />She mentioned networking if you were reading above. Volovik refers to superfluid helium and all his work explicitly shows the similarities between spacetime and condensed matter systems. As far as my opinion, if you have a lattice and each point has time reversal symmetry (protected) it cancels out however if you add frustration based on the spin system (see heisenberg) you get Sheeverhttps://www.blogger.com/profile/12931916936543585461noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-57489507250293388732017-10-22T18:03:02.560-04:002017-10-22T18:03:02.560-04:00The constituents of a space-time substructure mate...The constituents of a space-time substructure material would have to exist... but do not have to be similar to known macroscopic material constituents. Space is not a normal substance therefore it's constituents don't have to be "normal". Been researching this for years from a line of research the branched into this area and could go on at length speaking to what and how MainframeIIhttps://www.blogger.com/profile/11823729042174227458noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-21165116976681364062017-10-22T16:00:12.569-04:002017-10-22T16:00:12.569-04:00Hi Sabine,
I like your ideas about defects in spa...Hi Sabine,<br /><br />I like your ideas about defects in space, and space being made of something. What are your thoughts that matter is the defects in space, and the defects and the fields they create are an alteration in expression of the something that space is made of. Where both the defect and the fields are the only thing that moves through the something, but the actual granular Michael John Sarnowskihttps://www.blogger.com/profile/00528454593064091302noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-54039490757092611532017-10-22T12:37:03.667-04:002017-10-22T12:37:03.667-04:00Space may not be as immaterial as we thought.... ...<i>Space may not be as immaterial as we thought.... What if the fluid analogy is more than an analogy? Maybe space-time really behaves like a fluid; maybe it is a fluid.</i><br /><br />This seems puzzling to me. Ordinary material substances (such as fluids) have constituent parts that move inertially in time through some (supposedly empty) space. If space(time) itself is a material (or at Amoshttps://www.blogger.com/profile/00595591283398023248noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-58243138909104204962017-10-22T00:35:21.991-04:002017-10-22T00:35:21.991-04:00sorry..but giving a space-time a material fluidic ...sorry..but giving a space-time a material fluidic substructure constituting its continuum (mechanically and explicitly) does not separate space and time as exclusive and does not invalidate Einstein's GRT...it just gives it cause for their dependency. Both the experience of distance and time are emergent from the superfluidic substructure of space, where the curvature of space-time is a MainframeIIhttps://www.blogger.com/profile/11823729042174227458noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-86560440588172197812017-10-21T19:58:16.210-04:002017-10-21T19:58:16.210-04:00Thank-you for this link. Using a quantum aether co...Thank-you for this link. Using a quantum aether condensate for a black hole seems like a really potentially fruitful approach to unification of black hole physics with quantum uncertainty. Of course, there is still a fundamental dephasing necessary a la continuous spontaneous localization to finally complete unification with a quadratic Hamiltonian...or at least, that what seems to work.steve agnewhttps://www.blogger.com/profile/00177693538649923112noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-69574831760823387102017-10-21T14:09:12.420-04:002017-10-21T14:09:12.420-04:00By analogy, would sound also be similar?
The &quo...By analogy, would sound also be similar?<br /><br />The "perfect fluid" comes to mind.PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-49425317227614000532017-10-21T14:05:03.245-04:002017-10-21T14:05:03.245-04:00This fluid "substrate" analogy seems to ...This fluid "substrate" analogy seems to chime with the older analogy of viewing space as having a variable refractive index (determined by matter distributions) p, that gravitational induced light bending can be viewed according to an aether based Snell's law. What makes it more instructive as an analogy is not clear. Perhaps, that polarisation states of gravitational waves can be Anonymoushttps://www.blogger.com/profile/07790042974347244193noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-35647283631724279802017-10-21T11:34:37.336-04:002017-10-21T11:34:37.336-04:00Would love to read a blog post outlining your reas...Would love to read a blog post outlining your reasons for not being convinced ;)DanGemhttps://www.blogger.com/profile/05186974389201084819noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-14759741856014991682017-10-21T11:02:21.111-04:002017-10-21T11:02:21.111-04:00@Paolo "More like liquid crystal? One of its ...@Paolo "<i>More like liquid crystal? One of its properties is chirality.</i>"<br /><br />Chiral optical effects do not measure geometric chirality, stereograms below, or even require it (achiral silver thiogallate's 522°/mm rotation). Physics' chirality excludes chiral geometric Eötvös experiments. Given baryogenesis, this should set off alarms.<br /><br />http://Uncle Alhttps://www.blogger.com/profile/05056804084187606211noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-64627165948471116742017-10-21T09:36:24.523-04:002017-10-21T09:36:24.523-04:00Dan,
I looked at it but wasn't convinced, so ...Dan,<br /><br />I looked at it but wasn't convinced, so I stayed away from it. Same with string theory I may add. I pay for my scientific atheism by being basically unemployable now. Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-5814598364206056042017-10-21T09:32:37.406-04:002017-10-21T09:32:37.406-04:00Arun,
It doesn't. It's why I write it bre...Arun,<br /><br />It doesn't. It's why I write it breaks the union between space and time. Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-9496240043709309502017-10-21T07:23:40.092-04:002017-10-21T07:23:40.092-04:00Thanks for the great blog. It's written at jus...Thanks for the great blog. It's written at just the right level for me as the maths of most of what you discuss would be beyond me these days! I just have a question about loop quantum gravity.<br /><br />Have you never worked on it because that's just the way things worked out? Or have you looked at it and decided that it's not the route to quantum gravity? And if so why not?<br /><DanGemhttps://www.blogger.com/profile/05186974389201084819noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-34409716281611902852017-10-21T07:14:18.835-04:002017-10-21T07:14:18.835-04:00How does a fluid analog of general relativity avoi...How does a fluid analog of general relativity avoid having a preferred reference frame?Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.com