tag:blogger.com,1999:blog-22973357.post368863203825543250..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: Physics Bits and BitesSabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger26125tag:blogger.com,1999:blog-22973357.post-48974536523852443932010-05-10T09:23:45.241-04:002010-05-10T09:23:45.241-04:00Hi Stefan,
thanks.
Best, KayHi Stefan,<br /><br />thanks.<br /><br />Best, KayKay zum Feldehttps://www.blogger.com/profile/04233793196547147876noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-35126770670626114082010-05-09T17:19:35.628-04:002010-05-09T17:19:35.628-04:00Hi Kay,
these "thermodynamic and transport p...Hi Kay,<br /><br />these "thermodynamic and transport properties" (at least in the context of QCD and heavy ion collisions) mean properties such as shear and bulk viscosity, thermalization time, and drag force on quarks (which is related to the jet quenching, because it implies dissipation of energy and momentum). <br /><br />I do not know much more about these topics- maybe you will stefanhttps://www.blogger.com/profile/09495628046446378453noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-26257695177758190602010-05-09T10:26:15.787-04:002010-05-09T10:26:15.787-04:00Hi Stefan, hi Bee,
do you know, what thermodynami...Hi Stefan, hi Bee,<br /><br />do you know, what thermodynamic and transport properties of a strongly coupled QFT are related to properties of the black hole geometry ?<br /><br />I found this in the article by Klebanov and Maldecena.<br /><br />Best, KayKay zum Feldehttps://www.blogger.com/profile/04233793196547147876noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-23399276740656673242010-05-08T11:23:52.019-04:002010-05-08T11:23:52.019-04:00Hi Stefan, hi Bee,
thank you for explaining. Best...Hi Stefan, hi Bee,<br /><br />thank you for explaining. Best, KayKay zum Feldehttps://www.blogger.com/profile/04233793196547147876noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-73235626874871736632010-05-06T18:36:07.545-04:002010-05-06T18:36:07.545-04:00Hi Steven,
Define "momentum space", ple...Hi Steven,<br /><br /><i>Define "momentum space", please Stefan. ...</i><br /><br />While writing the post I was painfully aware that there are plenty of technical terms in all three items which I just had to presume to be known. (Though I did delete a quote from the abstract of the PRL on tetrahedron packing about the "translational and orientational correlation functions which stefanhttps://www.blogger.com/profile/09495628046446378453noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-85982562261882379342010-05-06T13:51:52.550-04:002010-05-06T13:51:52.550-04:00Hi Kay,
A jet, usually a di-jet, are two showers ...Hi Kay,<br /><br />A jet, usually a di-jet, are two showers of secondary particles that are produced from QCD scattering processes. The particles participating in the elementary scattering process can't be observed in the detector because of confinement. What happens is that they fragment into color-neutral hadrons, and these are then measured.<br /><br />Because of energy and momentum Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-26484989003739423062010-05-06T12:30:30.837-04:002010-05-06T12:30:30.837-04:00Hi Bee,
so a perfect fluid has a negligible shear...Hi Bee,<br /><br />so a perfect fluid has a negligible shear viscosity and is its constituents are strongly coupled. When quarks and gluons are not in asymtotic freedom they are strongly coupled. Physicists assumed that when temperatures are high enough quarks and gluons are separated from themselves and form the quark gluon plasma (QGP). The QGP has a very low shear viscosity. Physicists say Kay zum Feldehttps://www.blogger.com/profile/04233793196547147876noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-24926831195952587942010-05-06T06:33:35.327-04:002010-05-06T06:33:35.327-04:00Hi Steven,
Momentum space is but one of the many ...Hi Steven,<br /><br />Momentum space is but one of the many spaces in physics which provides a place that affords physicists some room for their thoughts to exist as to have certain aspects of nature considered.. Difficulty in their conception only arises when they or others take these spaces more seriously than has been demonstrated to be warranted by reality :-)<br /><br />Best,<br /><br />PhilPhil Warnellhttps://www.blogger.com/profile/15671311338712852659noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-18059215779328406312010-05-06T01:48:37.052-04:002010-05-06T01:48:37.052-04:00Hi Kay,
Excellent :-) There's many things I d...Hi Kay,<br /><br />Excellent :-) There's many things I don't understand either, but if I can be helpful, let me know. Best,<br /><br />B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-24354109885976721502010-05-06T01:22:58.095-04:002010-05-06T01:22:58.095-04:00Surely all the readers who find my husband so fasc...Surely all the readers who find my husband so fascinating are able to <a href="http://en.wikipedia.org/wiki/Momentum_space" rel="nofollow">use Google?</a>Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-22741800487747983402010-05-05T21:14:22.935-04:002010-05-05T21:14:22.935-04:00Going from real space to momentum space
Define &q...<i>Going from real space to momentum space</i><br /><br />Define "momentum space", please Stefan. I know what it is, but many of your readers who find you fascinating, don't. Thanks.Steven Colyerhttps://www.blogger.com/profile/10435759210177642257noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-59433582532588797602010-05-05T16:28:17.162-04:002010-05-05T16:28:17.162-04:00Hello Georg,
I think Paul Chaikin is an experimen...Hello Georg,<br /><br />I think <a href="http://www.physics.nyu.edu/~pc86/index.html" rel="nofollow">Paul Chaikin</a> is an experimentalist, but with a strong connection to theory - or the other way round ;-). Anyway, he is one of the authors of "<a href="http://books.google.com/books?id=P9YjNjzr9OIC&printsec=frontcover" rel="nofollow">Principles of Condensed Matter Physics</a>", a stefanhttps://www.blogger.com/profile/09495628046446378453noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-60208968017626854312010-05-05T09:27:38.902-04:002010-05-05T09:27:38.902-04:00Hi Bee,
thank you, I've red the article of &q...Hi Bee,<br /><br />thank you, I've red the article of "Physics Today". I didn't understand everything. However I understood the basics, I guess.<br /><br />Best, KayKay zum Feldehttps://www.blogger.com/profile/04233793196547147876noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-81816074907998790442010-05-05T05:56:48.843-04:002010-05-05T05:56:48.843-04:00Hello Stefan,
is that Prof. Paul M. Chaikin in the...Hello Stefan,<br />is that Prof. Paul M. Chaikin in theoretical <br />physics?<br />What he did (or better let do by <br />some innocent children) is a kind of <br />experimental work, isn't it?<br />Archimedes as a young man made some <br />half-spheres, a cylinder and cones <br />from wood with equal ground plane and height on a lathe and demonstrated <br />to the Academy of Alexandria the Georghttps://www.blogger.com/profile/02538391164351204407noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-53353547866040671642010-05-04T20:19:41.695-04:002010-05-04T20:19:41.695-04:00For some of your readers here is some info to help...For some of your readers here is some info to help them along.<br /><br /><br /><a href="http://eskesthai.blogspot.com/2010/02/article-from-new-york-times-and-mor.html" title="Since then, however, theorists have revisited their calculations and found that the quark soup can be either a liquid or a gas, depending on the temperature, he explained." rel="nofollow">Article From New York Times and PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-2059043990964865432010-05-04T20:10:48.283-04:002010-05-04T20:10:48.283-04:00In more cordial days:)
Wiping away some discussio...In more cordial days:)<br /><br />Wiping away some discussion comments is a common practise with some blog hosts "after the fact" to keep some clean lines.:)<br /><br />I am sure some remember Walter and Peter's final say on the topic of microscopic blackholes. Sorry if it's brought up again, but it was part of the idea behind the dissipation of cosmic particles in collision.DidPlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-7048145805773418942010-05-04T17:06:34.897-04:002010-05-04T17:06:34.897-04:00Hi Phil,
I’m particularly intrigued by the one ab...Hi Phil,<br /><br /><i>I’m particularly intrigued by the one about the school kids packing tetrahedral dice into fish bowls and such to produce densities higher than current theoretical limits.</i><br /><br />Indeed - it's a bit of a pity that the high school kids didn't make it on the list of authors of the PRL - but it seems they are acknowledged in the paper. Anyway, this is a stefanhttps://www.blogger.com/profile/09495628046446378453noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-12645212782643277772010-05-04T12:55:52.852-04:002010-05-04T12:55:52.852-04:00The most important thing is to be motivated by you...<i>The most important thing is to be motivated by your own intellectual curiosity.<b>KIP THORNE</b></i><br /><br />I was visiting Clifford's blog posting article the night before you posted Stefan.:)<br /><br />This topic has always been of interest to me, as I can attest by my presence at Clifford's postings in this regard. All research material I have done over the years lead me to thisPlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-89778679324561821462010-05-04T10:45:24.264-04:002010-05-04T10:45:24.264-04:00A pair of pseudotetrahedra fused base to base with...A pair of pseudotetrahedra fused base to base with concave faces, the three-armed spirallohedron, is exactly space-filling,<br /><br />http://mathworld.wolfram.com/images/eps-gif/RhombicSpiral3_500.gif <br />http://www.astro.uu.nl/~snik/NTS/QTS-stacked.jpg <br /> Symmetry: Culture and Science 11[1-4] 293 (2000)<br /><br />Physical theory is obsessed with fundamental intrinsic (intensive) Uncle Alhttps://www.blogger.com/profile/05056804084187606211noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-76516145340699027002010-05-04T09:56:42.187-04:002010-05-04T09:56:42.187-04:00Hi Stefan, Thanks for the link. I should point out...Hi Stefan, Thanks for the link. I should point out all the articles in the Physics Today May edition are about the subject. My article with Peter leads off (and readers can learn a bit about how the computations work there - see e.g. my blog for more) but it is followed by two articles by Peter and Barbara Jacak, and by John Thomas, that go in depth on the experimental side of things. (We all cvjhttps://www.blogger.com/profile/11877721142551713474noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-86373364656364720972010-05-04T09:16:57.323-04:002010-05-04T09:16:57.323-04:00Hi Kay:
I'd recommend you read either one of ...Hi Kay:<br /><br />I'd recommend you read either one of the links in this post... Best,<br /><br />B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-31232660353737445592010-05-04T09:16:17.771-04:002010-05-04T09:16:17.771-04:00Hi Bee,
what is the ADS/CFT correspondence and ho...Hi Bee,<br /><br />what is the ADS/CFT correspondence and how is it related to String theory ?<br /><br />Best, KayKay zum Feldehttps://www.blogger.com/profile/04233793196547147876noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-43477147454716494592010-05-04T07:28:13.919-04:002010-05-04T07:28:13.919-04:00Hi Steven,
I understand your point about geometry...Hi Steven,<br /><br />I understand your point about geometry perhaps being at the heart of it all and yet through the exploration of it logic was actually defined as to challenged to be what perhaps not as represented as being how we thought that it was; as the Pythagoreans discovered about the nature of even the simplest of geometric form. So I’m in the mind as Decartes was first to make Phil Warnellhttps://www.blogger.com/profile/15671311338712852659noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-18479876409119222962010-05-04T06:45:50.700-04:002010-05-04T06:45:50.700-04:00Before Mathematics there was Logic, Phil. From Log...Before Mathematics there was Logic, Phil. From Logic grew two great fields of study: Mathematics, and Science (as Physics). Logic then went to the realm of Philosophy, where it stayed for millenia until Charles Babbage and others brought it back in the brand spanking new field of Computer "Science."<br /><br />AND gates. OR gates. NOR gates. It all comes down to that, hmm?<br /><br />Steven Colyerhttps://www.blogger.com/profile/10435759210177642257noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-42892923556537782242010-05-04T06:19:31.673-04:002010-05-04T06:19:31.673-04:00Hi Stefan,
Thanks for all those happenings that h...Hi Stefan,<br /><br />Thanks for all those happenings that have caught your attention as of late. I’m particularly intrigued by the one about the school kids packing tetrahedral dice into fish bowls and such to produce densities higher than current theoretical limits. It is indeed interesting that the higher density ones being very disordered and yet perhaps not to be unexpected. <br /><br />Phil Warnellhttps://www.blogger.com/profile/15671311338712852659noreply@blogger.com