tag:blogger.com,1999:blog-22973357.post8785230098909335118..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: Comments temporarily disabledSabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger9125tag:blogger.com,1999:blog-22973357.post-4026074601315418222009-01-18T01:17:00.000-05:002009-01-18T01:17:00.000-05:00If your space has a loophole, presumably it is at ...If your space has a loophole, presumably it is at the cost of a symmetry.....Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-81408787138133611492009-01-17T18:33:00.000-05:002009-01-17T18:33:00.000-05:00Hi Neil:That's a different issue. You were asking ...Hi Neil:<BR/><BR/>That's a different issue. You were asking whether Noether's theorem generalizes to N dimensions. Yes, it does. What you are taking about now is the question what symmetries you can have in N dimensions. <BR/><BR/>I have no clue what loophole in Noether's theorem Plato thinks he has discovered. <BR/><BR/>Best,<BR/><BR/>B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-58339201711412291702009-01-17T16:56:00.000-05:002009-01-17T16:56:00.000-05:00Thanks, Bee. I don't get all that as a middle-brow...Thanks, Bee. I don't get all that as a middle-brow but I've seen quotes like, "In three dimensions, a vector is dual to a scalar. This means we can dualize all vectors in our three-dimensional action and obtain an action that only consists of scalar fields and a metrical field." But I think related to the above but more interesting: only in three dimensions can angular momentum be represented as Neil Bateshttps://www.blogger.com/profile/04564859009749481136noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-16299374346295472112009-01-17T15:56:00.000-05:002009-01-17T15:56:00.000-05:00Oooh, I didn't mean to imply a connection between ...Oooh, I didn't mean to imply a connection between the first paragraph of my above comment and the following two.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-468484873885811482009-01-17T15:54:00.000-05:002009-01-17T15:54:00.000-05:00Well, some comments are challenged even when not d...Well, some comments are challenged even when not disabled.<BR/><BR/>Neil: Yes. Noether's theorem has nothing to do with the number of dimensions. What matters is the symmetry of the system (or its absence). If you e.g. have a spacetime that is not translation invariant to begin with (because some particular submanifold is 'special', for example because we sit on it) you have no reason to expect Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-44855148132883447342009-01-17T13:22:00.000-05:002009-01-17T13:22:00.000-05:00Well, with no particular topic posted may I ask he...Well, with no particular topic posted may I ask here: Does Noether's Theorem generalize to universes analogous to ours but with other number of space dimensions? It seems like it should, but I've seen various statements that action etc. has special properties in three-D space.Neil Bateshttps://www.blogger.com/profile/04564859009749481136noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-3566586408351527972009-01-17T04:09:00.000-05:002009-01-17T04:09:00.000-05:00Hi Arun,“The politically correct term is "challeng...Hi Arun,<BR/><BR/>“The politically correct term is "challenged", not "disabled".”<BR/><BR/>In the context it’s usually applied the challenge is on going and therefore let’s hope it doesn’t qualify as being so defined.<BR/><BR/>Best,<BR/><BR/>PhilPhil Warnellhttps://www.blogger.com/profile/15671311338712852659noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-14792698437830100352009-01-16T23:11:00.000-05:002009-01-16T23:11:00.000-05:00The politically correct term is "challenged", not ...The politically correct term is "challenged", not "disabled".Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-9795241369204437352009-01-16T17:39:00.000-05:002009-01-16T17:39:00.000-05:00http://www.cnn.com/2009/TECH/ptech/01/16/virus.dow...http://www.cnn.com/2009/TECH/ptech/01/16/virus.downadup/index.html<BR/><BR/>Microcap - when the worst is good enough.Anonymousnoreply@blogger.com