tag:blogger.com,1999:blog-22973357.post646382866725243213..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: Gambini and Pullin: A First Course in Loop Quantum GravitySabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger21125tag:blogger.com,1999:blog-22973357.post-40678127780589552642012-02-28T08:58:42.987-05:002012-02-28T08:58:42.987-05:00Hi N,
I am afraid, if the "three roads"...Hi N,<br /><br />I am afraid, if the "three roads" were too technical, then this book will not solve the problem. Unless that is the problem was lack of equations. <a href="http://www.amazon.com/Martin-Bojowald/e/B003KTROH0" rel="nofollow">Martin Bojowald</a> has written a book, maybe this is useful. (I have it, but got stuck in chapter 2. He covers extensively all sorts of tests of Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-85678548616799341062012-02-28T08:53:03.391-05:002012-02-28T08:53:03.391-05:00Hi Bee,
Some time ago I read Lee Smolin's &qu...Hi Bee,<br /><br />Some time ago I read Lee Smolin's "Three Roads to...", very readable, but I admit I did not understand, well, almost anything.<br /><br />This one, is it closer to, well, not exactly a layman (I am a - retired - EE Engineer)?<br /><br />all the best,<br /><br />N.Nhttps://www.blogger.com/profile/17277418652411278565noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-16289356479700214082012-02-28T05:33:00.939-05:002012-02-28T05:33:00.939-05:00I've been joking Gloria looks like right out o...I've been joking Gloria looks like right out of a cookie advertisement: blond, blue-eyed, beaming at you if you just hand her something, may that be a plush toy, a cookie, or an empty bottle ;o)<br /><br />PS: There's something very wrong with the comment feature this morning.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-63725640719413188742012-02-27T20:23:31.757-05:002012-02-27T20:23:31.757-05:00The rational head knows that a baby cannot meaning...The rational head knows that a baby cannot meaningfully endorse a book. But just that smile makes me want to read the book.Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-20705433293113629212012-02-27T08:32:27.661-05:002012-02-27T08:32:27.661-05:00I just wanted to second this review. I got a copy ...I just wanted to second this review. I got a copy of the book a few months ago, and I think Sabine says exactly what I would say about it :-)Chanda @ Disordered Cosmoshttps://www.blogger.com/profile/11462022695342468789noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-76721065304330427072012-02-26T13:21:48.168-05:002012-02-26T13:21:48.168-05:00I very much look forward to counting the number of...I very much look forward to counting the number of times that the names Delaunay and Voronoi are mentioned.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-29562307960678699002012-02-26T10:28:03.835-05:002012-02-26T10:28:03.835-05:00Whatever interest Gloria's mom will pique her ...Whatever interest Gloria's mom will pique her interest too! She's no doubt observed that books are great friends with her mom. :)Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-40784897267151630722012-02-26T02:51:59.489-05:002012-02-26T02:51:59.489-05:00Hi Juan,
Who is "J"? I didn't actua...Hi Juan,<br /><br />Who is "J"? I didn't actually "give" the book to Gloria. She pulled it out among the pillows and blankets. (I have the unfortunate habit to sleep with books. Though the books aren't the main problem; the main problem are the pens.) However, she was to my surprise very very careful with the book, she opened and closed it a few times and looked very Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-14003515842086731832012-02-25T19:42:05.461-05:002012-02-25T19:42:05.461-05:00Bee - I think your exchange with Glotis speaks to ...Bee - I think your exchange with Glotis speaks to what the authors were getting at with their caution of using the web as an introduction to the subject, especially as string theory is the "in" theory and certainly has a lot more vested interest in terms of time and careersAnonymous Snowboarderhttps://www.blogger.com/profile/13705929076819672791noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-52024344052636947532012-02-25T13:31:01.240-05:002012-02-25T13:31:01.240-05:00OMG, BEEEE!!! How could you give such a big book t...OMG, BEEEE!!! How could you give such a big book to your child?LOL Do you remember what J did to a girl with a QM book? I am wondering what J would do to your precious child!Jhttps://www.blogger.com/profile/01942050607289418780noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-30977512495524111302012-02-25T13:21:10.503-05:002012-02-25T13:21:10.503-05:00Hi Bee,
Not a Pollock fan eh, then I would advise...Hi Bee,<br /><br />Not a Pollock fan eh, then I would advise you keep the lids on your paints tight as from that look in Gloria’s eyes she seems inspired to express herself abstractly. That is taking into account Gloria’s nature and that of LQG could be a serious thing; that is especially if she comes to realize her work not to be background dependent. Then again I suppose if all else fails youPhil Warnellhttps://www.blogger.com/profile/15671311338712852659noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-62182625442768756172012-02-25T12:56:54.467-05:002012-02-25T12:56:54.467-05:00Bee I see that you point to the second edition of ...Bee I see that you point to the second edition of kiefer's book. Note that there is a <a href="http://www.amazon.com/Quantum-Gravity-Third-International-Monograph/dp/0199585202/ref=sr_1_6?s=books&ie=UTF8&qid=1330191913&sr=1-6" rel="nofollow">third enchanced edition</a> coming on July. So your readers if they are patient enough should wait until July to purchase the new version. ItGiotishttps://www.blogger.com/profile/03594944884584261018noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-31472072780455698782012-02-25T12:35:28.703-05:002012-02-25T12:35:28.703-05:00Hi Phil,
The cover is also pretty actually. It ha...Hi Phil,<br /><br />The cover is also pretty actually. It has a Pollockian spin-network on it (if you look closely, you can see it on the picture). I'm not a Pollock-fan (too messy) but it works nicely for the purpose at hand. Best,<br /><br />B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-12412900316063838702012-02-25T12:28:23.425-05:002012-02-25T12:28:23.425-05:00Hi Giotis,
Do I find it odd that every side point...Hi Giotis,<br /><br />Do I find it odd that every side points at the other's faults while praising their own virtues? No, I can't say I'm surprised. Best,<br /><br />B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-80546093932561521392012-02-25T11:52:51.503-05:002012-02-25T11:52:51.503-05:00Quantum gravitation and the standard model both ar...Quantum gravitation and the standard model both arrive massless - elegant and unphysical. Add artificial curve fittings (SUSY, riiight).<br /><br />"<i>the reformulation of general relativity in terms of Ashtekar's variables</i>" Ashtekar variables are chiral decomposition of connection one-forms of the local Lorentz group re the Immirzi parameter (arxiv:1104.1800, 1108.0816). Uncle Alhttps://www.blogger.com/profile/05056804084187606211noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-9021111489940376852012-02-25T11:02:02.161-05:002012-02-25T11:02:02.161-05:00Hi Bee,
All I have to say if its good enough for ...Hi Bee,<br /><br />All I have to say if its good enough for Gloria then it should be good enough for me!Phil Warnellhttps://www.blogger.com/profile/15671311338712852659noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-4828006931972159012012-02-25T10:53:01.191-05:002012-02-25T10:53:01.191-05:00Bee don't you think is odd that people practic...Bee don't you think is odd that people practicing LQG accuse String theory for lack of predictivity when their theory not only doesn't predict anything at all at the low energy effective world but it can't even make contact with established theories like GR.<br /><br />They could raise theoretical arguments in favour of LQG but predictivity is not their strong point. They don't Giotishttps://www.blogger.com/profile/03594944884584261018noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-51798312473842147012012-02-25T09:58:13.591-05:002012-02-25T09:58:13.591-05:00Hi Giotis,
The ambiguity in the Hamiltonian const...Hi Giotis,<br /><br />The ambiguity in the Hamiltonian constraint is also briefly addressed in the last chapter of the book. They basically acknowledge it and say more work is required. And yes, LQG doesn't tell you anything about matter (not unless you believe all matter is braids that is), but then it wasn't meant to provide unification. Best,<br /><br />B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-80730804500346310142012-02-25T09:38:36.071-05:002012-02-25T09:38:36.071-05:00Not to mention that LQG has nothing to say about m...Not to mention that LQG has nothing to say about matter. Practically it is compliant with everything.Giotishttps://www.blogger.com/profile/03594944884584261018noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-62455899534518328712012-02-25T09:32:59.611-05:002012-02-25T09:32:59.611-05:00"[I]t is refreshing that in loop quantum grav..."[I]t is refreshing that in loop quantum gravity there are not many things that can be tweaked to make the theory agree with experiment...'<br /><br />With the large amount of ambgiguity inherited by the Hamiltonian constraint (which determines the physical states too) I can't see why this is true.Giotishttps://www.blogger.com/profile/03594944884584261018noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-20830725178706298992012-02-25T09:30:15.869-05:002012-02-25T09:30:15.869-05:00Five Stars! Thanks, Bee, this is EXACTLY the book ...Five Stars! Thanks, Bee, this is EXACTLY the book I have been dying to see being written!<br /><br />Any idea when Lee Smolin's new book is coming out? Co-Written with a professional Philosopher, this is another book I've been longing to read. Thanks again! :-)Steven Colyerhttps://www.blogger.com/profile/10435759210177642257noreply@blogger.com