tag:blogger.com,1999:blog-22973357.post5475889598309680492..comments2021-05-11T18:03:27.965-04:00Comments on Sabine Hossenfelder: Backreaction: M is for Maggot, N is for NonsenseSabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger37125tag:blogger.com,1999:blog-22973357.post-18634702213422829592019-08-02T21:40:05.826-04:002019-08-02T21:40:05.826-04:00Infinity appears in many (!) physical theories and...Infinity appears in many (!) physical theories and experiments.<br />We were taught how to escape from this problem<br />But what if INFINITY is a real physical concept ?<br />For example: there is only one physical INFINITE reality -<br />the spacetime between billion and billion galaxies.<br />All the rest is limited and finite. <br />=======israel sadovnik socratushttps://www.blogger.com/profile/05455782761752129698noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-42906273258971271632019-07-31T02:53:20.413-04:002019-07-31T02:53:20.413-04:00What about singularity of particles as perfect poi...What about singularity of particles as perfect points? - what is a common belief e.g. for electron and would mean infinite energy of its electric field alone.<br />I was searching in literature for experimental evidence of this belief for electron and it usually leads to 1988 Dehmelt's g-factor argument, where he extrapolates from proton and triton - literally by fitting parabola to two Jarek Dudahttps://www.blogger.com/profile/11358050996148333936noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-53714435913535717222019-07-28T10:09:04.598-04:002019-07-28T10:09:04.598-04:00In many physical experiments the INFINITY appears....In many physical experiments the INFINITY appears.<br />Sooner or later all Fields are finished by ''waves collapse'' and then <br />needs ''method of renormalization'' to bring them again to existence.<br />Sometimes Electron's parameters become INFINITE.<br />Questions:<br />What if INFINITY is a real concept ?<br />Can INFINITY be understood by Physical Lawsisrael sadovnik socratushttps://www.blogger.com/profile/05455782761752129698noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-2193239690358876482019-07-27T23:24:07.021-04:002019-07-27T23:24:07.021-04:00http://backreaction.blogspot.com/2019/07/m-is-for-...http://backreaction.blogspot.com/2019/07/m-is-for-maggot-n-is-for-nonsense.html<br />This thread is about limits and infinities<br />Mathematically their interaction was explained<br />by ''method of renormalization''<br />Physical aspect is unknow.<br />=== israel sadovnik socratushttps://www.blogger.com/profile/05455782761752129698noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-48108443164830543092019-07-21T07:15:10.762-04:002019-07-21T07:15:10.762-04:00@opamanfred: This would be the case if there is no...@opamanfred: This would be the case if there is no mass-gap separating quantum states of a de Sitter vacuum from an anti-de Sitter vacuum. One has to consider however there are topological differences between the dS and AdS. The dS in n+1 dimensions is basically R×M^n, for the reals R representing time and M^n either an n-dimensional sphere or Euclidean flat space. The anti-de Sitter spacetime isLawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-65272934078861618372019-07-21T07:10:17.230-04:002019-07-21T07:10:17.230-04:00It suggests that consistent quantum gravity requir...It suggests that consistent quantum gravity requires certain relationships between gravitational and nongravitational forces. It would be surprising if this was only true in AdS space. Mitchellhttps://www.blogger.com/profile/10768655514143252049noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-21237133527089235242019-07-20T23:13:28.877-04:002019-07-20T23:13:28.877-04:00Opamanfred,
I am not sure what makes you say that...Opamanfred,<br /><br />I am not sure what makes you say that. What exactly do you mean with "continuously"? I have named above an example (planar black holes) this is not the case and you probably also know that the FRW solutions with positive and negative cosmological constant don't continuously deform into each other. What my (admittedly cryptic) sentence was referring to is that Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-50758495983562832022019-07-20T14:50:25.794-04:002019-07-20T14:50:25.794-04:00Hi Sabine, !
Please feel free to disregard
My c... Hi Sabine, !<br /> Please feel free to disregard<br /> My comment from last night.<br /> All apologies, I was Extremely <br /> tired and (usually :) know better than to comment when I'm drifting in and out of sleep.<br /> I understand perfectly what You're saying and,tbh, I have <br /> no idea What I was talking about! lol<br /> Just wanted to say<br /> Welcome Back!<br />A.C.https://www.blogger.com/profile/08901144737333895284noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-66589488534884450622019-07-20T12:29:18.013-04:002019-07-20T12:29:18.013-04:00But in classical General Relativity, one can move ...But in classical General Relativity, one can move continuously from a positive CC to a negative one, going through the value zero, without any singularity, if I'm not mistaken. Why is it different in quantum gravity? <br />From you brief sentence on why string theorists prefer to work with AdS space, it is not obvious that there is a singularity at Lambda=0opamanfredhttps://www.blogger.com/profile/07148586222290109507noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-43364132071047457172019-07-20T08:51:52.828-04:002019-07-20T08:51:52.828-04:00This critter is usually called a worm in informal ...This critter is usually called a <i>worm</i> in informal English, not a maggot.Peter Shorhttps://www.blogger.com/profile/13823970640202949073noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-86841267971630498732019-07-20T08:35:11.510-04:002019-07-20T08:35:11.510-04:00I thought about commenting on this, but time and s...I thought about commenting on this, but time and space were limits. The LIGO detection of gravitational radiation has placed bounds on graviton masses. The Compton wavelength λ = ħ/mc as 1.6×10^{16}m or about 1.6 light years or a mass m_g < 8×10^{-23}eV --- ref https://arxiv.org/abs/1706.01812 .<br /><br />The mass of a graviton corresponds to a longitudinal degree of freedom, and this is notLawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-17632728661277083672019-07-20T06:47:22.188-04:002019-07-20T06:47:22.188-04:00Don Foster: hey, the caterpillar it is basically a...Don Foster: <i>hey, the caterpillar it is basically apple, right?</i><br /><br />So I can call myself a Vegan if I restrict my diet to vegan animals? Good news, I don't have to give up Barbecue night!<br /><br />I suppose cannibals can claim they are vegetarians if they only consume Vegan people.Dr. A.M. Castaldohttps://www.blogger.com/profile/17988116835722393503noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-54945055015921034102019-07-20T04:22:25.185-04:002019-07-20T04:22:25.185-04:00This is indeed what I mean. My comment was prompte...This is indeed what I mean. My comment was prompted by this section of your post: "Anti De Sitter (AdS) space, to remind you, is a space with a negative cosmological constant. It is popular among string theorists because they know how to make calculations in this space. Trouble is, the cosmological constant in our universe is positive."<br /><br />For the record I completely agree with dlbhttps://www.blogger.com/profile/00647687145267016748noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-41172410999848130522019-07-20T03:47:42.568-04:002019-07-20T03:47:42.568-04:00“… when we take the limit in which the number of c...<i>“… when we take the limit in which the number of constituents of a system becomes infinitely large, we see phase transitions … ”</i><br />A. Zee dubs this “<a href="https://books.google.de/books?id=n8Mmbjtco78C&pg=PA292&lpg=PA292&dq=%22The+secret+is+that+an+infinite+sum+of+terms+each+of+which+may+be+analytic+in+some+variable+need+not+be+analytic+in+that+variable.%22" rel="nofollow"Reimondhttps://www.blogger.com/profile/04669340425105889539noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-40521632167416688872019-07-20T02:43:06.694-04:002019-07-20T02:43:06.694-04:00Haha, now I get it :p Sorry for being slow. Haha, now I get it :p Sorry for being slow. Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-56253313216591098202019-07-20T01:33:42.457-04:002019-07-20T01:33:42.457-04:00A wormhole in an apple is not speculative, it is r...A wormhole in an apple is not speculative, it is reality and we know what caused it and how.martenhttps://www.blogger.com/profile/02423871089614417690noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-71987560431667248992019-07-20T00:34:04.926-04:002019-07-20T00:34:04.926-04:00Sabine,
A small biological quibble for both you a...Sabine,<br /><br />A small biological quibble for both you and Berry. The critter you would like to avoid biting is actually the vegetarian caterpillar of the codling moth that grazes within fruit on six continents. The maggot is the mostly carnivorous larva of the various fly species that are also well traveled. Folks making cider usually throw in the whole apple, caterpillar and all because – Don Fosterhttps://www.blogger.com/profile/04814669413022486958noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-50504486408166131182019-07-20T00:24:24.326-04:002019-07-20T00:24:24.326-04:00neo,
I am not aware of a relation. neo,<br /><br />I am not aware of a relation. Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-43825532322257542492019-07-20T00:18:17.393-04:002019-07-20T00:18:17.393-04:00Arun,
Oh, I see. This is a most excellent questio...Arun,<br /><br />Oh, I see. This is a most excellent question. I speculated about it in <a href="https://fqxi.org/community/forum/topic/3065" rel="nofollow">this essay</a>. The brief answer is there aren't any known examples but if there were it would basically mean the end of reductionism. <br /><br />(I realized after writing the essay that there are some examples of the behavior I am Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-34078507856794056422019-07-20T00:14:10.528-04:002019-07-20T00:14:10.528-04:00Marten,
You mean wormholes in Anti De Sitter spac...Marten,<br /><br />You mean wormholes in Anti De Sitter space? Let me just say that combining several speculative ideas doesn't give you a less speculative idea. Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-5425219850470555042019-07-20T00:13:04.884-04:002019-07-20T00:13:04.884-04:00Dlb,
If by cosmological constant you mean an add...Dlb, <br /><br />If by cosmological constant you mean an additional term in the action and by vacuum energy you mean the qft contribution (and not the source of the field equations in vacuum), then yes. But I don't understand what this has to do with the current blogpost. Are you sure this comment is in the right thread?Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-40976074191374802742019-07-19T22:35:32.080-04:002019-07-19T22:35:32.080-04:00"Take the example of massive gravity. In gene..."Take the example of massive gravity. In general relativity, gravitational waves propagate with the speed of light and the particle associated with them – the graviton – is massless. You can modify general relativity so that the graviton has a mass. However, if you then let the graviton mass go to zero, you do not get back general relativity. The reason is that if the graviton mass is not neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-48302595246179847532019-07-19T19:18:38.872-04:002019-07-19T19:18:38.872-04:00This has been something I have pondered over a lot...This has been something I have pondered over a lot. It does appear that quantum gravity prefers the AdS spacetime with the negative curvature Λ < 0. This is certainly the case for AdS/CFT correspondence. Supersymmetry is broken with positive energy as well. The observable universe is de Sitter-like with Λ > 0 and putting string theory here and potentially much of quantum gravity is maybe Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-78002594329214652112019-07-19T16:02:58.580-04:002019-07-19T16:02:58.580-04:00I suppose the question is - are there discontinuit...I suppose the question is - are there discontinuities in renormalization "group" flows?Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-35874877103609075782019-07-19T14:46:47.208-04:002019-07-19T14:46:47.208-04:00What about wormhole theorists?What about wormhole theorists?martenhttps://www.blogger.com/profile/02423871089614417690noreply@blogger.com