tag:blogger.com,1999:blog-22973357.post4239009870959631899..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: UnparticlesSabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger16125tag:blogger.com,1999:blog-22973357.post-56259241309236533812007-09-26T05:38:00.000-04:002007-09-26T05:38:00.000-04:00Hi Bee, not sure if you've gone in a circular argu...Hi Bee, not sure if you've gone in a circular argument with nothing conclusive.<BR/><BR/>If things behave differently at the quantum level and known physics breaks down at the planck scale - then there must be a different between the things that are large (galaxies, blackholes) and the things subatomic or microstate ... albeit the large proceeds from the small, the small is altered by the large.<QUASAR9https://www.blogger.com/profile/00593390598251093182noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-34049516833982304912007-09-26T05:31:00.000-04:002007-09-26T05:31:00.000-04:00When we see an iceberg, we know we are only seeing...When we see an iceberg, we know we are only seeing the TIP of the iceberg above the water<BR/><BR/>We know about 9/10s is below<BR/>We can speculate or guesstimate its mass, density & volume, but we can never be quite sure what is below the water or its shape, just from what we observe above.<BR/><BR/>After all there could be a submarine (or asteroid) trapped in the frozen ice below.QUASAR9https://www.blogger.com/profile/00593390598251093182noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-50101866922149533022007-09-24T06:58:00.000-04:002007-09-24T06:58:00.000-04:00I don't blame Georgi either ... it's not as if he ...I don't blame Georgi either ... it's not as if he <I>needs</I> a few hundred extra citations, he's just having fun. It's not his fault that people are hanging around until the LHC turns on.<BR/><BR/>I remember seeing his paper 'The Flavor Problem' from 1986 - 3 journal pages with not a single equation, but people still work on the flavor problem, it's a real and difficult one, and the paper has Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-71896290064740039612007-09-23T12:27:00.000-04:002007-09-23T12:27:00.000-04:00Hi Arun,Sure, in principle you can push the terms ...Hi Arun,<BR/><BR/>Sure, in principle you can push the terms from one side to the other, i.e. it could be a modification of GR. There are people working on that as well. Let me see... for example<BR/><BR/><I>Extended Theories of Gravity and their Cosmological and Astrophysical Applications</I><BR/>Capozziello and Francaviglia<BR/><A HREF="http://www.arxiv.org/abs/0706.1146" REL="nofollow">arXiv: Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-48194414025839692272007-09-23T11:06:00.000-04:002007-09-23T11:06:00.000-04:00Dear Bee,What I mean is that observations - of ty...Dear Bee,<BR/><BR/>What I mean is that observations - of type I supernovae or of galactic rotation curves or of astronomical lensing or CMBR - are all interpreted within the context of General Relativity and the models spawned from it and therefrom we deduce the existence of stuff that isn't described by the Standard Model.<BR/><BR/>Most likely, we will be able add terms to the Standard Model Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-52450011010036201612007-09-23T10:56:00.000-04:002007-09-23T10:56:00.000-04:00Hi Arun:I am not perfectly sure I understand your ...Hi Arun:<BR/><BR/>I am not perfectly sure I understand your question. What do you mean with "observations in the context of a theory"? We have a whole number of observations, i.e. data. These can be described very good by using GR (the concordance model) with two additional terms that do not correspond to baryonic matter. What is so far lacking though is any microscopic explanation for these Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-30036635356685663312007-09-23T10:11:00.000-04:002007-09-23T10:11:00.000-04:00Dear Bee,This is an off-topic question. Is it tru...Dear Bee,<BR/>This is an off-topic question. Is it true that all that we know about dark matter/dark energy is derived from observations in the context of a theory of gravity (GR or its Newtonian approximation where applicable)?Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-73261266272151438302007-09-21T21:44:00.000-04:002007-09-21T21:44:00.000-04:00you can also use\usepackage[sort&compress]{natbib}...you can also use<BR/>\usepackage[sort&compress]{natbib}<BR/>to prevent arXiv from hyperlinking the citations see<BR/>http://arxiv.org/help/faq/mistakes#nohypertexAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-39070747881099771722007-09-21T16:15:00.000-04:002007-09-21T16:15:00.000-04:00Anonymous: Oh really? Maybe what you mean is that ...Anonymous: Oh really? Maybe what you mean is that anyone could do what Georgi has done? So why don't you do it then, huh?<BR/><BR/>This is like what people used to say about electronic music. "Oh, but they're just pressing some buttons to create music. That's not difficult." But of course people who said that didn't actually create anything themselves.<BR/><BR/>Bee: there's the cite package (\Rienhttps://www.blogger.com/profile/13374605389155800194noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-35627342433229149142007-09-21T15:16:00.000-04:002007-09-21T15:16:00.000-04:00Whether Georgi is interesting can be empirically d...Whether Georgi is interesting can be empirically determined. His big problem is visible emergence from a vast inertial background of business as usual.<BR/><BR/>http://scitation.aip.org/prl/covers/99_12.jsp<BR/> "...these yield a new combined limit (blue ellipse) in <B>good</B> agreement with the standard model (black star)."<BR/><BR/>Unless I'm blind, it is in <B>poor</B> agreement. There is Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-7265351141134191622007-09-21T08:35:00.000-04:002007-09-21T08:35:00.000-04:00Hi Thomas L., Hi Christophe:Thanks for the clarifi...Hi Thomas L., Hi Christophe:<BR/><BR/>Thanks for the clarification on scale invariance. I admit I've been very brief with that. Maybe somewhat too brief.<BR/><BR/>Hi Thomas D,<BR/><BR/>Yes, that is exactly what I mean. The problem with that citation scheme is that it's crucial to act <B>fast</B>, because those who follow will cite those who came earlier. I doubt everybody has read all the papers Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-67404661093783112292007-09-21T08:00:00.000-04:002007-09-21T08:00:00.000-04:00More importantly, the unparticle stuff is a case s...More importantly, the unparticle stuff is a case study in how to launch a bandwagon. Write a paper that allows people to re-do calculations using techniques with which they are already familiar. Don't ask anyone to learn anything new. Georgi has made a career out of this kind of thing.<BR/><BR/>In evolutionary theory, one has become familiar with the idea that the success of really primitive Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-9156447071580029252007-09-21T07:39:00.000-04:002007-09-21T07:39:00.000-04:00The main objection to unparticles, as a theoretica...The main objection to unparticles, as a theoretical idea, is that they don't seem to solve any problem in particle theory. The Standard Model on its own has enough problems and unexplained features. To consider physics Beyond the Standard Model, one should have a reasonable expectation that the new physics throws some light on them, rather than being just something else added on. <BR/><BR/>It's Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-61114526766015251472007-09-21T07:17:00.000-04:002007-09-21T07:17:00.000-04:00Interesting article, but the definition of scale i...Interesting article, but the definition of scale invariance may need to be more precisely articulated. There are reasons to believe that the actual "zoom law" in the universe is not necessarily the simple multiplicative law Howard Georgi used ("<EM>A scale transformation multiplies all dimensional quantities by a rescaling factor raised to the mass dimension</EM>" on page 2 of hep-ph/0703260). Christophe de Dinechinhttps://www.blogger.com/profile/15212549796119667462noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-27075869584315428652007-09-21T02:06:00.000-04:002007-09-21T02:06:00.000-04:00The Koch curve does not look the same if you scale...The Koch curve does not look the same if you scale in arbitrarily, only if you do it in powers of 3. This is different from a percolation cluster or a self-avoiding walk, which statistically look the same on arbitrary scales. This is related to the latter having a *local* scale symmetry.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-87146008759515788262007-09-20T21:46:00.000-04:002007-09-20T21:46:00.000-04:00This comment has been removed by the author.Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.com