tag:blogger.com,1999:blog-22973357.post4319417228617223349..comments2019-01-21T06:23:56.045-05:00Comments on Backreaction: Guest Post: Garrett Lisi on Geometric NaturalnessSabine Hossenfelderhttps://plus.google.com/111136225362929878171noreply@blogger.comBlogger108125tag:blogger.com,1999:blog-22973357.post-7525037189118263232018-12-14T10:53:14.099-05:002018-12-14T10:53:14.099-05:00A reduction localizes particles, sets them on mass...A reduction localizes particles, sets them on mass shell and makes a tiny, tiny backreaction in GR possible. We know already how to evolve bosons and fermions on a <b>static</b> curved spacetime. Thus, it simply could be a dynamics of tiny steps of unitary evolution on a (intermediary static) curved spacetime followed by reduction and tiny, tiny backreactions everywhere, all the “time”.<br />The Reimondhttps://www.blogger.com/profile/04669340425105889539noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-43339265865358670162018-12-14T10:52:51.646-05:002018-12-14T10:52:51.646-05:00What are the clues and glues to join matter and sp...What are the clues and glues to join matter and spacetime? Well, the factors of the actions of GR c^4/16πG∼10^43 and QM ℏ∼10^-34 are about 77 orders apart. Thus, when a small amount of QM particles with a total mass/energy m becomes entangled and is in superposition, we expect spacetime to be still smooth. But when more and more QM particles join and the total mass m reaches a certain threshold ?Reimondhttps://www.blogger.com/profile/04669340425105889539noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-72185830202592966532018-12-14T10:52:32.815-05:002018-12-14T10:52:32.815-05:00Central extension:
The two revolutions in physics ...Central extension:<br />The two revolutions in physics SR and QM (6) can be regarded as central extensions of the Galilean algebra. <br />The generators for translation in time and space are H=∂/∂t and P=∂/∂x and the Galilean boost is K=-t∂/∂x. We see that [K,P]=0 commutates. A central extension, deformation introduces a non-commutation, e.g. it changes [K,P]=0 to [K,P]<>0. <br />In SR theReimondhttps://www.blogger.com/profile/04669340425105889539noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-85954601889579471402018-12-14T10:52:12.185-05:002018-12-14T10:52:12.185-05:00Local/”non-local”(3a):
“Diffeomorphism … it acts n...Local/”non-local”(3a):<br /><i>“<a href="https://books.google.de/books?id=16UgAwAAQBAJ&pg=PA42&lpg=PA42&dq=%22It+acts+nonlocally+on+all+the+fields,+by+pulling+them+back,%22" rel="nofollow">Diffeomorphism … it acts nonlocally</a>“</i><br />Einstein had quarrels that the metric was not uniquely determined in relation to coordinates. His breakthrough in GR came when he realized that <a Reimondhttps://www.blogger.com/profile/04669340425105889539noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-25703810742263574052018-12-14T10:51:36.609-05:002018-12-14T10:51:36.609-05:00Garrett,
You said: “We need to resolve the dichot...Garrett,<br /><br />You said: <i>“We need to resolve the dichotomy between marble and wood, and have quantum marble for both sides.” </i> Let me list some more dichotomies. Maybe I can contribute a little bit, but again I only know the basic stuff.<br /><br />On/off mass shell:<br />First this one, since you said: <i> “I have mostly concentrated on unification of off-shell symmetries, …”</i>.<br Reimondhttps://www.blogger.com/profile/04669340425105889539noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-87426540211678005912018-12-11T20:25:28.087-05:002018-12-11T20:25:28.087-05:00"I wasn't talking about rubik cubes speci..."I wasn't talking about rubik cubes specifically. But about the relationship between raising and lowering operations and twisting moves. And then also about the relation to braids and particle charges and preons. (This has been a wide ranging discussion!) Personally, I think our known elementary particles really are fundamental. But that's an opinion mostly on aesthetics."<br />WRLhttps://www.blogger.com/profile/04323354407920835050noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-48112038675957599212018-12-11T20:06:54.702-05:002018-12-11T20:06:54.702-05:00Odd that you said that, bee. That is very much th...Odd that you said that, bee. That is very much the same thing Murray Gell-Mann said when I suggested that they explore partitioned strings (so as to model preon algebra at root level) _before_ building the Super-conducting Supercollider - in the 80s! <br />Yet even today there is no appropriate venue. I've even had to split my talks into two general areas in order to present a WRLhttps://www.blogger.com/profile/04323354407920835050noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-23667656579407048772018-12-11T17:11:51.685-05:002018-12-11T17:11:51.685-05:00The original modified BF theory for Gravity was Pl...The original modified BF theory for Gravity was Plebanski's complex chiral Lagrangian. The Weyl curvature was the Lagrange multiplier that ensured the complex bivector came from the co-frame in the field equations. Problem was that "off shell" extraneous conditions needed to be imposed on the complex bivector to ensure reality of metric. <br /><br />Also in being complex using bothLee McCullochJameshttps://www.blogger.com/profile/02361355053331325032noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-5633754164411374262018-12-03T11:22:01.944-05:002018-12-03T11:22:01.944-05:00@ Garrett, I have a little erratum. It is B{\a&quo...@ Garrett, I have a little erratum. It is B{\a"}cklund transformations and not Beckland.Unknownhttps://www.blogger.com/profile/01108801719325422187noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-41429545745223889582018-12-03T05:38:49.705-05:002018-12-03T05:38:49.705-05:00Garrett,
Since you appear to say I have somewhat ...Garrett,<br /><br />Since you appear to say I have somewhat of the right idea this then leads to my next question. The infinite stack of E8 roots in my sense might then possibly be seen as due to an infinite sequence of prolongations, such as Beckland transformations. Is this possible?Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-39546893608522257292018-12-03T00:07:35.182-05:002018-12-03T00:07:35.182-05:00Lawrence Crowell,
Infinite-dimensional Lie groups...Lawrence Crowell,<br /><br />Infinite-dimensional Lie groups are fascinating! Yes, your description of E9 is correct. The root system is an infinite "stack" of E8 roots. In general, one generates the Cartan matrix from the Dynkin diagram, and then generates the root system (or a truncation of it) from the Cartan matrix, and also can build the Lie algebra generators and structure using Garretthttps://www.blogger.com/profile/03136765358626033631noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-87416334203824282882018-12-02T12:25:57.224-05:002018-12-02T12:25:57.224-05:00Garret said, in reply to ben6993:
"I wasn'...Garret said, in reply to ben6993:<br />"I wasn't talking about rubik cubes specifically. But about the relationship between raising and lowering operations and twisting moves. And then also about the relation to braids and particle charges and preons. (This has been a wide ranging discussion!) Personally, I think our known elementary particles really are fundamental. But that's an ben6993https://www.blogger.com/profile/11246990849377879772noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-82716635690586933672018-12-01T14:06:10.429-05:002018-12-01T14:06:10.429-05:00@ Garrett: I have not studies these extended E8 gr...@ Garrett: I have not studies these extended E8 groups. So before I should do this I might want to ask a few questions. The E8+ group or E9 is an extension of the E8 with the addition of a ● in the Dynkin diagram. This might then be compared to extending the E8 with an A1 ~ SU(2). This is a form of Kac-Moody algebra, as is my understanding. I am not exactly sure how that is done.<br /><br />The Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-84981103426729241752018-11-29T14:10:42.360-05:002018-11-29T14:10:42.360-05:00Reimond,
I have mostly concentrated on unification...Reimond,<br />I have mostly concentrated on unification of off-shell symmetries, including spacetime, before reduction to subgroups via symmetry breaking and further dynamical reduction to solutions of the EOM -- but Wigner's Little Group as it applies to such solutions are certainly on my mind.<br /><br />Lawrence Crowell, <br />Yes, this is all correct. Infinite dimensional, generalized LieGarretthttps://www.blogger.com/profile/03136765358626033631noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-9034325227290694572018-11-28T20:38:18.675-05:002018-11-28T20:38:18.675-05:00Fun read. Have you mentored any students? Or since...Fun read. Have you mentored any students? Or since maybe you've been out of the academic mainstream, have you thought about what would be your rough equivalent of a student?Anonymous cowardhttps://www.blogger.com/profile/00966645751635389218noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-1363977402905051612018-11-28T03:09:42.184-05:002018-11-28T03:09:42.184-05:00Enrico,
Your comment is wrong on so many levels I...Enrico,<br /><br />Your comment is wrong on so many levels I don't even know where to start. To begin with, photons don't have "their own internal clock". Also, guess what, light always moves at the speed of light. Having said this, I have no time and no patience to correct all those mistakes and since I don't want to contribute to the spread of misinformation, I will not Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-13536167885168861602018-11-27T20:34:46.704-05:002018-11-27T20:34:46.704-05:00Garrett,
A = My theory does not have a big bang si...Garrett,<br />A = My theory does not have a big bang singularity.<br />B = My theory proves big bang singularity does not exist.<br />B does not follow from A. I suppose you mean A<br /><br />Time asymmetry is an artefact of how we slice spacetime. Photons have their own internal clock (frequency = f) but we measure time with Earth reference frame clock. When a photon redshift due to spacetime Enricohttps://www.blogger.com/profile/11062542721973950650noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-83916418881118363192018-11-27T12:41:36.364-05:002018-11-27T12:41:36.364-05:00Garrett, It's refreshing to read you think abo...Garrett, It's refreshing to read you think about the influence bias may have on your work, I laughed at your quip, <i>"But I'm not wrong. ;)"</i> <br /><br />I would advise you that I believe no matter how much effort you put into being objective it is impossible for humans to be completely objective. Also, the deeper you are embedded in an idea the harder it becomes to extract Louis Tagliaferrohttps://www.blogger.com/profile/16698865662162457632noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-36647035164299079752018-11-27T06:03:34.230-05:002018-11-27T06:03:34.230-05:00So this means E8+++ = E11, or is similar. I am not...So this means E8+++ = E11, or is similar. I am not an expert at these, but E9 has an additional su(2) Dynkin node, which as I recall means an extension of E8 with a ladder of states assigned to each of the weights of E8. E11 has a more complex form, I would suppose an A3 Lie valued extension.<br /><br />Are there forms of the Jordan 3x3 matrix?<br /><br />As pointed out this is a bit in Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-56423749959104560672018-11-27T05:36:06.055-05:002018-11-27T05:36:06.055-05:00Garrett,
Just a short question: Does Wigner´s lit...Garrett,<br /><br />Just a short question: Does Wigner´s little group play any role in your reasoning?<br />I ask since Igor a while ago said: <i>“… in a way that generalizes the unitary transformations that realizes the Lorentz boots …”</i><br />Just started to read your “Lie Group Cosmology” – I first had to catch up.Reimondhttps://www.blogger.com/profile/04669340425105889539noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-41585500725218024362018-11-27T01:17:41.520-05:002018-11-27T01:17:41.520-05:00Enrico,
The classical vacuum I see in Lie Group Co...Enrico,<br />The classical vacuum I see in Lie Group Cosmology is de Sitter spacetime, which expands forever but doesn't have a singularity. The big bang is just what it looks like back when you can't see earlier. And, correct me if I'm wrong, but I don't think mass-energy conservation holds in an expanding spacetime, because it's not time symmetric.<br /><br />ben6993,<br />IGarretthttps://www.blogger.com/profile/03136765358626033631noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-23411694798272574742018-11-26T15:32:52.150-05:002018-11-26T15:32:52.150-05:00Garrett, I watched the wonderfully done TED talk i...Garrett, I watched the wonderfully done TED talk in 2008, this morning, on your E8 theory on my sister's computer, where unfortunately I can't respond. I'm on my notebook computer and just tried to access that talk, but it was no longer available, or possibly was the wrong one. Anyway, in it you mention two types of gravitational charge, and I was curious what was meant by that. David Schroederhttps://www.blogger.com/profile/18048116250413347228noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-7753059435280502632018-11-26T14:29:21.607-05:002018-11-26T14:29:21.607-05:00If you work hard enough, and are smart enough, you...If you work hard enough, and are smart enough, you will find science that supports your beliefs. Science is about seeing with complete objectivity (easier said than done for everyone), and not seeing what you think is there. I remember you talking fondly about Lie groups many years ago, it doesn't surprise me you've found reasons to think your on the right track.<br /><br />Humany Louis Tagliaferrohttps://www.blogger.com/profile/16698865662162457632noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-5494913245236952572018-11-26T14:09:37.803-05:002018-11-26T14:09:37.803-05:00Garret, ben6993
You might find the paper "Th...Garret, ben6993<br /><br />You might find the paper "The (16,6,2) Designs" by Assmus and Salwach to be of modest interest. There are three non-isomorphic designs with those parameters. One of those designs has a subgroup that fixes a block and corresponds with the symmetry group of the cube. Another of those designs also has a relationship with cube faces. In this case, the subgroup mlshttps://www.blogger.com/profile/15862021650071892590noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-25307822424092468322018-11-26T09:54:27.910-05:002018-11-26T09:54:27.910-05:00Garrett said: "We need to resolve the dichoto...Garrett said: "We need to resolve the dichotomy between marble and wood, and have quantum marble for both sides."<br /><br />I have absolutely no idea what <b>physical</b> picture you have in mind. Do you? I mean, after another decade of heroic mathematical struggle, when you finally put your hands on that quantum marble, will you be able to say anything more than predict yet another Yehonatan Knollhttps://www.blogger.com/profile/09680318989713357978noreply@blogger.com