tag:blogger.com,1999:blog-22973357.post8742894442631752346..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: 10 effects you should have heard ofSabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger59125tag:blogger.com,1999:blog-22973357.post-84022385158501056262008-03-31T14:42:00.000-04:002008-03-31T14:42:00.000-04:00That should be: There is no definition here of a t...That should be: There is <B>no</B> definition <B>here</B> of a thermal state in terms of particles.Peterhttps://www.blogger.com/profile/08654675777726560464noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-48670432580651894942008-03-31T14:10:00.000-04:002008-03-31T14:10:00.000-04:00Been away for a few days, come back to find an int...Been away for a few days, come back to find an interesting post that mentions Hawking effect without Unruh effect, think must comment, find almost none of the other 10 effects mentioned, LOTS of discussion of why Unruh is/not same as Hawking. Less than 100 posts, so I read them all -- but quickly.<BR/><BR/>To me, the Unruh effect says a thermal state gives the same measurement results as the Peterhttps://www.blogger.com/profile/08654675777726560464noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-84301983574585393442008-03-27T22:12:00.000-04:002008-03-27T22:12:00.000-04:00A thermal photon bath suggests a mixed, decoherent...A thermal photon bath suggests a mixed, decoherent whatever state, one point of disagreement 'tween the inertial and accelerated observer. Another point of disagreement seems to be what a thermometer would read. How about entropy?Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-91482922420203126702008-03-27T20:45:00.000-04:002008-03-27T20:45:00.000-04:00OK here is my interpretation of the Bee-Clovis Unr...OK here is my interpretation of the Bee-Clovis Unruh effect discussion. Clovis claims the photon decay needs a thermal bath explanation while Bee claims it just needs the math of a thermal bath explanation. It does sound like one of those quantum computer debates where someone like Deutsch is claiming real many-worlds paths for the computations and others say it's just the math of Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-49533328138450685392008-03-27T14:14:00.000-04:002008-03-27T14:14:00.000-04:00Bee,There are some things you may think you unders...Bee,<BR/><BR/>There are some things you may think you understand, when in fact you have got only a superficial knowledge of them. To recognize so, when it happens, is a good step in order to learn better. It happens to us all, I have came across such a situation so many times. This time I believe it is hapenning to you. <BR/><BR/>The frustration of this discussion is not related to lack of Clovishttps://www.blogger.com/profile/08921327103613284595noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-11016750050893710872008-03-27T14:07:00.000-04:002008-03-27T14:07:00.000-04:00Hi Clovis,Well, now you know why I find this discu...Hi Clovis,<BR/><BR/>Well, now you know why I find this discussion frustrating. Nevertheless, thanks for dropping in anyhow. Best,<BR/><BR/>B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-49218260470331704522008-03-27T14:04:00.000-04:002008-03-27T14:04:00.000-04:00Bee,- "Yes, that's what I am trying to tell you al...Bee,<BR/><BR/>- "Yes, that's what I am trying to tell you all the time: The tensor transformation of zero is zero. What is wrong with that? There is nothing inconsistent about it, and no need for an additional effect. If I summarize your above argument which was meant to explain the necessity of the Unruh effect it says: one needs the Unruh effect, because without the Unruh effect one wouldn't Clovishttps://www.blogger.com/profile/08921327103613284595noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-74182849751251661182008-03-27T13:55:00.000-04:002008-03-27T13:55:00.000-04:00Hi Count:Not that it is of any actual relevance, b...Hi Count:<BR/><BR/>Not that it is of any actual relevance, but almost all of the 'posts deleted by the author' you see are corrections of typos or likewise. Best,<BR/><BR/>B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-65022747506735525922008-03-27T13:53:00.000-04:002008-03-27T13:53:00.000-04:00Hi Clovis,Your argumentation is an excellent examp...Hi Clovis,<BR/><BR/>Your argumentation is an excellent example for a circular argument, I am beginning to like it.<BR/><BR/><I>Wrong. You know, in the Unruh effect the energy-momentum tensor is zero for the inertial guy. It is zero also for the accelerated one, since a zero tensor is zero in whatever frame you transform it. Still, the accelerated guy will see a bath of particles. QFT in curved Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-91255623961329228162008-03-27T13:38:00.000-04:002008-03-27T13:38:00.000-04:00Bee,- "But for this to be possible you don't need ...Bee,<BR/><BR/>- "But for this to be possible you don't need the Unruh effect. All you need is SR and the tensor transformation."<BR/><BR/>Wrong. You know, in the Unruh effect the energy-momentum tensor is zero for the inertial guy. It is zero also for the accelerated one, since a zero tensor is zero in whatever frame you transform it. Still, the accelerated guy will see a bath of particles. QFT Clovishttps://www.blogger.com/profile/08921327103613284595noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-87005692286193294922008-03-27T13:12:00.000-04:002008-03-27T13:12:00.000-04:00island,As a blog developer, you have the option to...island,<BR/><BR/>As a blog developer, you have the option to delete your own comments too:)<BR/><BR/>I saved the author of this site the option to delete a double post. My bad:)PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-25410330014798178052008-03-27T13:09:00.000-04:002008-03-27T13:09:00.000-04:00In regards to Andrews link to the article by Amand...In regards to Andrews link to the article by Amanda Geftner.<BR/><BR/>I was curious as well to how one may actually <A HREF="http://eskesthai.blogspot.com/2008/03/tipping-lightcones-and-escape-velocity.html" REL="nofollow" TITLE="Tipping LightCones and the Escape Velocity of a Photon">describe the process of the horizon</A> and work toward that horizon in terms of it's geometry?<BR/><BR/><B>PlatoPlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-90498438769644847802008-03-27T13:06:00.000-04:002008-03-27T13:06:00.000-04:00Information is lost on this blog, though:"Comment ...Information is lost on this blog, though:<BR/><BR/>"<B>Comment deleted</B> <BR/>This post has been removed by the author.<BR/><BR/>11:47 AM, March 27, 2008"<BR/><BR/><BR/>:)<BR/><BR/><BR/><BR/>Anyway, I was wondering about the following detailed balance argument about black holes in thermal equilibrium with thermal radiation. The black holes mass should remain stationary when it is in a box Count Iblishttps://www.blogger.com/profile/07429017672028256731noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-7478228687796482612008-03-27T13:03:00.000-04:002008-03-27T13:03:00.000-04:00Hi Clovis,Well, I do agree that sometimes people n...Hi Clovis,<BR/><BR/>Well, I do agree that sometimes people need to carefully think by themselves. To repeat once again: you argue that for the accelerated observer to agree with the non-accelerated one (e.g. on the decay of the proton) you need the Unruh effect, because otherwise it would not be consistent. Your argument is based on saying the accelerated observer should be able to "describe it Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-69235391682076642812008-03-27T12:48:00.000-04:002008-03-27T12:48:00.000-04:00I tried looking for the 10 greatest experiments in...I tried looking for the 10 greatest experiments in concert with this blog entry. I have it somewhere on my site.<BR/><BR/>I have enjoyed Andrews contributions to your conversation on the Blackhole Paradox.<BR/><BR/>Sometimes when people do not see in the same way as another person there is a "potential there" for bringing perspective to an "ole situation."<BR/><BR/>Sometimes one has to give PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-5910521171001871822008-03-27T12:47:00.000-04:002008-03-27T12:47:00.000-04:00This comment has been removed by the author.PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-58793905789106394442008-03-27T12:45:00.001-04:002008-03-27T12:45:00.001-04:00Hi Andrew,You continue to misunderstand me. I don'...Hi Andrew,<BR/><BR/>You continue to misunderstand me. I don't 'belong to the school that says information is lost in black holes' (not sure I belong to any school). On the contrary, I am convinced information is not lost in black holes. I was merely trying to explain why your solution to the information loss problem doesn't even address the problem to begin with. Neither did I say I want to Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-16489308481778279362008-03-27T12:45:00.000-04:002008-03-27T12:45:00.000-04:00Hi Bee,Still I will comment on two things we do no...Hi Bee,<BR/><BR/>Still I will comment on two things we do not seem to be speaking the same language.<BR/><BR/>- "I have already explained you that if you're sitting in the spaceship you clearly are an accelerated observer. You can measure this. You do not expect an equivalence."<BR/><BR/>When I say that both observers (inertial and accelerated) must agree, I am not saying they should describe theClovishttps://www.blogger.com/profile/08921327103613284595noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-27535118245952576852008-03-27T11:06:00.000-04:002008-03-27T11:06:00.000-04:00Hi Bee, Thanks for your response - I'll make th...Hi Bee,<BR/> Thanks for your response - I'll make this my last comment! I'm a bit sorry other people haven't commented on this.<BR/> You seem to belong to the school that says information is lost in black holes? However, I still don't accept it (and I see Stephen Hawking changed his mind on this subject now believing that information is not lost after all, famously losing his bet - see thatAndrew Thomashttps://www.blogger.com/profile/03852211910001840777noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-52769418343008121942008-03-27T10:21:00.000-04:002008-03-27T10:21:00.000-04:00So, Dr Who, so refrigeration equipment that works ...So, Dr Who, so refrigeration equipment that works while cruising inertially in Minkowski spacetime will encounter a Unruh radiation thermal bath when accelerated, and not be able to achieve the same low temperature?Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-35858460949085782502008-03-27T10:13:00.000-04:002008-03-27T10:13:00.000-04:00Hi Andrew,but I fear we're getting to the stage of...Hi Andrew,<BR/><BR/><I>but I fear we're getting to the stage of over-analysis, and all this fuss about apparent "information loss" seems to be a classic case of over-analysis - imagining a problem when there is none.</I><BR/><BR/>Yeah indeed, I share this fear. The problem with this problem is that there have been so many different attempts to explain it that 95% of the publications on the matterSabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-34777924673758447402008-03-27T09:39:00.000-04:002008-03-27T09:39:00.000-04:00Hi Dr Who,Well. I can't recall how many times I've...Hi Dr Who,<BR/><BR/>Well. I can't recall how many times I've come across one or the other abuse of the equivalence principle but this one is news to me. I find it very unfortunate if textbooks motivate the Hawking effect with the Unruh effect, the Unruh paper was even published after Hawking's calculation. The situation for the Hawking effect is completely different: there are two asymptotically Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-72782067657711820922008-03-27T09:27:00.000-04:002008-03-27T09:27:00.000-04:00Well, Bee, this is the part where people start mum...Well, Bee, this is the part where people start mumbling about the principle of equivalence. My teacher defined the principle of equivalence as "the belief that it is possible to make the curvature tensor equal to zero by means of a coordinate transformation", and he praised it as being very clear and very falsifiable. That is, clearly false.....Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-21902177703819688582008-03-27T09:26:00.000-04:002008-03-27T09:26:00.000-04:00Hi Dr Who,Wow, a first :-) What stuns me about thi...Hi Dr Who,<BR/><BR/>Wow, a first :-) What stuns me about this admittedly is how little disagreement there is on the question. It makes me feel like I must be completely stupid, but whenever I look at the calculation its based on the same assumption that people just seem to take for granted? And if I start arguing with somebody they will come with all kinds of elaborated thought experiments and Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-32059714840180430082008-03-27T09:19:00.000-04:002008-03-27T09:19:00.000-04:00Hi Clovis,I think we're just running in circles, s...Hi Clovis,<BR/><BR/>I think we're just running in circles, so I think we better leave it at this. I have already explained you that if you're sitting in the spaceship you clearly are an accelerated observer. You can measure this. You do not expect an equivalence. If you have a particle in rest with the spacecraft, you would not expect it to behave as one in rest in an intertial frame. You can Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.com