tag:blogger.com,1999:blog-22973357.post2071815083618862425..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: Large Extra Dimensions - Not Dead YetSabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger31125tag:blogger.com,1999:blog-22973357.post-45461792597088574972012-12-26T12:46:48.837-05:002012-12-26T12:46:48.837-05:00So... we have models with extra dimensions!
Some ...So... we have models with extra dimensions!<br /><br />Some Models with some dimensions that did not expand.<br /><br />1. Are there models that analyse the conditions that could exist with all the dimensions at minimum length?<br /><br />2. Are there models that assume that all dimensions were bigger than our 3d space/time and that our 3d space time has shrung to its present size?<br /><br />jalhttps://www.blogger.com/profile/16969819389823705458noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-41584435110813259522012-12-23T06:49:17.717-05:002012-12-23T06:49:17.717-05:00As well, some familiarity with the subject for sur...As well, some familiarity with <a href="http://motls.blogspot.ca/2011/12/learning-from-theory-and-data-about-our.html" title="Learning from theory and data about our string vacuum" rel="nofollow">the subject</a> for sure.<br /><br /><i>Even the many theorists who are interested in how string theory connects to the real world don’t typically think much about what it means to test the theory. PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-45927372333983075312012-12-23T06:37:00.755-05:002012-12-23T06:37:00.755-05:00A crib sheet baseline for the generalities "...A <a href="http://seedmagazine.com/images/uploads/cribsheet9.pdf" rel="nofollow">crib sheet</a> baseline for the generalities "beyond the brain theories?":)<br /><br />Best,PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-39687541628642008552012-12-22T15:46:14.340-05:002012-12-22T15:46:14.340-05:00Bee,
Yes but if gravitational influences cross br...Bee,<br /><br />Yes but if gravitational influences cross branes then matter should clump over there in the same places it clumps over here because of that interaction. <br /><br />Also maybe the rules are different over there. Maybe the other brane is a kind of dual universe with supersymmetery particles rather than normal particles. So their particles will not interact with each other or with ppnlhttps://www.blogger.com/profile/01720719028496317693noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-82015546190499028732012-12-22T13:03:25.567-05:002012-12-22T13:03:25.567-05:00emily: thanks for your understanding.emily: thanks for your understanding.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-9388948549063009962012-12-22T13:03:07.798-05:002012-12-22T13:03:07.798-05:00Nemo: You'll have to register. That's why ...Nemo: You'll have to register. That's why the comments work so well. Blogger seems to be falling behind in many ways at this point, one can only hope that they're working on an update. (That would include, eg, the option to rate comments.)Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-32726368761942165112012-12-22T12:35:33.919-05:002012-12-22T12:35:33.919-05:00your pond, your rulesyour pond, your rulesemilycurioushttps://www.blogger.com/profile/16282076055198154167noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-89204824479618812892012-12-22T12:30:46.804-05:002012-12-22T12:30:46.804-05:00Thanks Bee for responding,
so I'll have to i...Thanks Bee for responding, <br /><br />so I'll have to ignore comments of people, who too often have nothing constructive to say, just by remembering their names and not reading these comments ...<br /><br />For me it is a bit unfortunate that the more interesting and nicer discussions take place on facebook. I highly distrust facebook, so I'll most probably not be able to read the Nemohttps://www.blogger.com/profile/15937686207028627202noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-82707726002170698342012-12-22T12:22:56.568-05:002012-12-22T12:22:56.568-05:00emilycurious: Your comments are entirely off-topic...emilycurious: Your comments are entirely off-topic. Since you seem to be new, please read the comment rules. If you have more off-topic comments I'll delete them. Best,<br /><br />B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-30575971770123251912012-12-22T12:21:25.345-05:002012-12-22T12:21:25.345-05:00Nemo: No, unfortunately Blogger doesn't have s...Nemo: No, unfortunately Blogger doesn't have such a feature. (Btw, it seems that discussion to my blogposts is more and more moving over to facebook, mostly because the comment feature is less cumbersome.)Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-2646267890692768132012-12-22T12:14:04.589-05:002012-12-22T12:14:04.589-05:00"Nemo", are your comments somehow more v..."Nemo", are your comments somehow more valid than anyone elses? Is this really how we wish science to be conducted in the 21st Century, by elitists?<br />I have no idea why my opinions should be labelled "trolling" any more than your tantrum.<br /><br />I'm sure I'm not as intelligent or as well read as you, yet, but I'm more than prepared to stand on the front emilycurioushttps://www.blogger.com/profile/16282076055198154167noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-59429895764180385522012-12-22T12:02:32.702-05:002012-12-22T12:02:32.702-05:00Sometimes I'd really like to be able to downvo...Sometimes I'd really like to be able to downvote or flag trolling comments, such as the one of "emilycurious" for example ...<br /><br />A feature similar to the one of Amazon, which allows one to ignore comments of specific people, would be helpful too to filter for the interesting contributions to the physics discussion and ignore the crap.<br /><br />Can something like this be Nemohttps://www.blogger.com/profile/15937686207028627202noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-45576901113577923632012-12-22T10:56:10.569-05:002012-12-22T10:56:10.569-05:00Hi Ppnl,
people have played with this idea a deca...Hi Ppnl,<br /><br />people have played with this idea a decade or so ago. You don't need the specific model that Cliff proposed for this, a vanilla ADD model will do. The brief summary is that it doesn't work because dark matter isn't just dark: It isn't distributed like it was normal matter that we just don't see. Its distribution is correlated with that of normal matter. It Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-29203683124246397252012-12-22T09:20:44.491-05:002012-12-22T09:20:44.491-05:00>does not matter for the argument
I was lookin...>does not matter for the argument<br /><br />I was looking for Smolin's new book - still as elusive as the dimensions in string theory apparently - your blog mentioned it in 2010 and then I clicked on the masthead for the latest post, hence I arrived at this point in time. I'm not paid to be a scientist or philosopher so perhaps my perspective doesn't count but in my humble opinionemilycurioushttps://www.blogger.com/profile/16282076055198154167noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-63404935903759568542012-12-22T07:25:09.810-05:002012-12-22T07:25:09.810-05:00So if gravitation travels between branes and that ...So if gravitation travels between branes and that other brane is so close then couldn't it be a good place to hide dark matter? Gravitationally it is there but it is 45 μm away in the wrong direction.ppnlhttps://www.blogger.com/profile/01720719028496317693noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-43857128853276673792012-12-22T06:54:34.609-05:002012-12-22T06:54:34.609-05:00Thanks for explaining the key ideas of these inter...Thanks for explaining the key ideas of these interesting models in a nice and understandable way here.<br /><br />I like this.Nemohttps://www.blogger.com/profile/15937686207028627202noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-80366719676578834672012-12-22T05:54:36.366-05:002012-12-22T05:54:36.366-05:00Kind of like the way the years have gone by and yo...Kind of like the way the years have gone by and your dealing with the issue of extra-dimension.:)<br /><br />I am still the incurable hopeless romantic about what we can see and what I suspect we don't see.....but that is not very kosher with the science is it?:)<br /><br />In the one sense, a very abstract theoretical idea about what can be married to "real life in nature's PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-7546960593266894522012-12-22T02:15:43.289-05:002012-12-22T02:15:43.289-05:00ppnl,
Could be another universe or, if the wrappi...ppnl,<br /><br />Could be another universe or, if the wrapping of the branes is more complicated, who knows, maybe it's the same. In any case, yes, they should influence each other gravitationally. This is the same, really, as with all the other braneworld scenarios. Best,<br /><br />B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-35266167366656785422012-12-22T02:13:36.612-05:002012-12-22T02:13:36.612-05:00Zephir,
So first you bring up some flat 3-dimensi...Zephir,<br /><br />So first you bring up some flat 3-dimensional space and then you don't know which space you are talking about? Could you please stop making such pointless comments then?<br /><br />Also, let me summarize the breadth of your knowledge about differential geometry: One curves a curvature with differential concept. I think you have a somewhat confused understanding of this, Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-36914274959211727752012-12-21T21:18:51.334-05:002012-12-21T21:18:51.334-05:00
Sort of undead physics?
Or maybe the living dead...<br />Sort of undead physics?<br /><br />Or maybe the living dead that cannot be killed scientifically?<br /><br />Whatever sticks to the wall?Robert L. Oldershawhttps://www.blogger.com/profile/15396555790655312393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-57084719571921121262012-12-21T20:03:00.401-05:002012-12-21T20:03:00.401-05:00
If one brane is our universe then what is the ot...<br /><br />If one brane is our universe then what is the other brane? And can gravitational influences go from one to the other?ppnlhttps://www.blogger.com/profile/01720719028496317693noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-15008032428611548992012-12-21T13:36:40.986-05:002012-12-21T13:36:40.986-05:00/*Which flat space? Which definition?*/
That'.../*Which flat space? Which definition?*/<br /><br />That's the good question - because even the seemingly empty space contains minuscule deforms: CMBR photons with their spin-1 and spin-2 components. So we have another example of extradimensions in vacuum fluctuations (after all, in the same way, like the Brownian noise at the 2D water surface would serve as an evidence of third dimension of Zephirhttps://www.blogger.com/profile/06010623752049244967noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-46933175353748243272012-12-21T12:47:10.587-05:002012-12-21T12:47:10.587-05:00End small dimensions with calculated versus measur...End small dimensions with calculated versus measured Rydberg formula or hyperfine transition (e.g, 21 cm line for hydrogen) for a high-Z hydrogen-like atom (re <a href="http://www.gsi.de/en/start/forschung/forschungsfelder/appa_pni_gesundheit/atomphysik/research/experimental_facilities/hitrap.htm" rel="nofollow">HITRAP</a>). Correct for spin-orbit interaction, non-point-charge nucleus plus smallUncle Alhttps://www.blogger.com/profile/05056804084187606211noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-52307083696416502472012-12-21T11:04:58.180-05:002012-12-21T11:04:58.180-05:00Hi Alexander,
Yes, the former. The string scale j...Hi Alexander,<br /><br />Yes, the former. The string scale just is not identical to the Planck scale. Best,<br /><br />B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-25005715174961967932012-12-21T11:03:45.422-05:002012-12-21T11:03:45.422-05:00Hi Phil,
It's not so easy because, as I wrote...Hi Phil,<br /><br />It's not so easy because, as I wrote, the 13/14 TeV are per proton collision, not per parton collision (a parton being a proton constituent). It is, simply speaking, very unlikely that 13 TeV go into a single parton collision. Exactly how unlikely depends on the "parton distribution functions". Basically, it's not enough to crank up the energy, you also have Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.com