tag:blogger.com,1999:blog-22973357.post8069648006612502128..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: Eppley and Hannah's thought experimentSabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger74125tag:blogger.com,1999:blog-22973357.post-53266620143625854262016-01-27T08:34:42.676-05:002016-01-27T08:34:42.676-05:00Hi Sabine, I am commenting on your old post becaus...Hi Sabine, I am commenting on your old post because we just had a discussion with some people which directly relates to the discussion here.<br /><br />I think Eppley and Hanna's argument have a different subtelty which has not been addressed and which touches the heart of the difference between gravity and electromagnetism.<br />The whole discussion of Eppley and Hannah, which you summarize lunhttps://www.blogger.com/profile/13611677760513109481noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-21549925884030050722012-01-26T01:51:29.283-05:002012-01-26T01:51:29.283-05:00Hi Arun,
Thanks for the reference, I'll look ...Hi Arun,<br /><br />Thanks for the reference, I'll look at that! Best,<br /><br />B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-27832994487886609842012-01-25T21:59:35.564-05:002012-01-25T21:59:35.564-05:00Dear Bee,
Any comments on this? It may be more ri...Dear Bee,<br /><br />Any comments on this? It may be more rigorous than Eppley and Hannah?<br /><br />http://arxiv.org/abs/quant-ph/0402092<br /><br />Inconsistency of quantum--classical dynamics, and what it implies<br />Daniel R. Terno<br />(Submitted on 13 Feb 2004)<br /><br /> A new proof of the impossibility of a universal quantum-classical dynamics is given. It has at least two Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-69259104811199505582012-01-18T01:26:02.991-05:002012-01-18T01:26:02.991-05:00Hi Unknown,
a),b),d) and c'): offer a motivat...Hi Unknown,<br /><br />a),b),d) and c'): offer a motivation for the layman why quantizing gravity is an endeavor worth engaging in. I don't see it as my task to convince everybody they should take up physics. This would be a nightmare. Best,<br /><br />B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-63648918634821500702012-01-17T11:22:17.455-05:002012-01-17T11:22:17.455-05:00Is this post meant to:
a)entertain the expert phys...Is this post meant to:<br />a)entertain the expert physicist<br />b)stimulate the budding physicist<br />c)inspire the layman to takeup physics(kinda like carr's book and ramanujam)<br />d)just a post<br /><br />This is my first post on your blog. I'm welcome.Unknownhttps://www.blogger.com/profile/03976157589798822472noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-57086962787888756782012-01-12T17:59:46.145-05:002012-01-12T17:59:46.145-05:00" It doe not seem at all unreasonable to me t..." It doe not seem at all unreasonable to me that if you moved quantum entanglement from the world of small and low energy to the world of large and high energy that the first thing that would change would be no wave function collapse when measuring the the state of one of the quantum entangled bodies."<br /><br />I should add that it is unproven that this thought experiment is possible Erichttps://www.blogger.com/profile/08213251864943443334noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-11098200620078390422012-01-12T16:50:24.747-05:002012-01-12T16:50:24.747-05:00Hi Arun and Andrew,
I know no one has commented on...Hi Arun and Andrew,<br />I know no one has commented on my earlier comment but I think one of my points has a bearing on this discussion. When physicists talk about the collapse of the wave function in quantum mechanics they refer implicitly to the realm of the small scale. Unfortunately, there is a vague and often changing definition in physics of the scale at which wave function collapse Erichttps://www.blogger.com/profile/08213251864943443334noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-88798999456009546552012-01-12T16:12:12.911-05:002012-01-12T16:12:12.911-05:00Arun,
Alternatively, I can take a fundamentalist ...Arun,<br /><br />Alternatively, I can take a fundamentalist Schrödinger view - that by measuring your part of the wavefunction, you have entangled yourself with the quantum state, and that it is only when I measure my part of the wavefunction that you collapse into a pure state consistent with my measurement. Or equivalently I can measure you and thereby collapse my half of the wavefunction. Of Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-83808861995038805022012-01-12T12:58:24.336-05:002012-01-12T12:58:24.336-05:00A quantum particle interacting with a classical ob...A quantum particle interacting with a classical object does not always constitute a measurement.<br /><br />e.g., light passing through optical glass; atoms in a magnetic trap.<br /><br />A measurement requires decoherence, something to carry away quantum phase information into the environment.<br /><br />In the thought experiment of a classical gravity wave scattering off of a quantum particle Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-7249582948229962932012-01-12T09:01:34.231-05:002012-01-12T09:01:34.231-05:00Hi Neil,
Maybe this helps. Best,
B.Hi Neil,<br /><br /><a href="http://arxiv.org/abs/quant-ph/9905050" rel="nofollow">Maybe this helps</a>. Best,<br /><br />B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-34556959545443777382012-01-12T08:51:11.552-05:002012-01-12T08:51:11.552-05:00Bee (if you're away, someone else please dig i...Bee (if you're away, someone else please dig in, this is IMHO a big deal), in any case it presses: what if I prepare an object with a definite momentum in an imaging interferometer, set up to do IFMs (or whatever method you please)? This is something we can really do, right? What kind of position measurement could an IFM return? Now what, how to square that with HUP?<br /><br />(I do need to Neil Bateshttps://www.blogger.com/profile/04564859009749481136noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-54804606450134294212012-01-12T08:49:21.431-05:002012-01-12T08:49:21.431-05:00This comment has been removed by the author.Neil Bateshttps://www.blogger.com/profile/04564859009749481136noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-49241186807266509862012-01-12T07:51:16.741-05:002012-01-12T07:51:16.741-05:00Bee,
I agree absolutely that something has to giv...Bee,<br /><br />I agree absolutely that something has to give. As far as we know, all current QM interpretations lead to absurdities, even without introducing GR. But different interpretations lead to different absurdities, and E&H only treated a subset of these.<br /><br />For example, in the EPR tests one could say that 'measurement' takes place only when the combined results are Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-73632796351574163982012-01-12T02:56:12.987-05:002012-01-12T02:56:12.987-05:00Hi Andrew,
EPR type tests have also conclusively ...Hi Andrew,<br /><br />EPR type tests have also conclusively shown that the correlation exists already while the both events are spacelike separated. Basically, you have to make them far enough apart and measure quickly enough to exclude a causal information exchange can have happened. This has meanwhile been done many times. Interesting though you say this, at the time E&H wrote the paper Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-53490836360274058892012-01-12T02:51:18.686-05:002012-01-12T02:51:18.686-05:00Hi Neil,
Well, I'd say if they manage to meas...Hi Neil,<br /><br />Well, I'd say if they manage to measure \Delta x \Delta p < 1/2, they have violated the uncertainty principle. Best,<br /><br />B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-58586579947471050302012-01-12T01:55:14.175-05:002012-01-12T01:55:14.175-05:00Rastus,
If it was true what you'd say, then w...Rastus,<br /><br />If it was true what you'd say, then we'd find momentum violation all the time and everywhere! Look, put the interaction into a box and look at it from far away. The asymptotic mass of a region is conserved, temporarily curving the background doesn't help you anything with that. That's exactly why I find it very unfortunate that the statement GR can violate Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-89519307930247034842012-01-11T23:35:30.850-05:002012-01-11T23:35:30.850-05:00My point is that violation of momentum conservatio...My point is that violation of momentum conservation is the obvious way out. This has been discussed particularly well by these people:<br /><br />http://tigger.uic.edu/~huggett/Nick/My%20Work_files/why.pdf<br /><br />[or search here:<br /><br />http://tigger.uic.edu/~huggett/Nick<br /><br />]<br />My additional point is that "gravitational energy" [and momentum] is an *extremely* Rastus Odinga Odingahttps://www.blogger.com/profile/09615544434035028500noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-20346951543420698102012-01-11T13:40:41.893-05:002012-01-11T13:40:41.893-05:00Well, not to hem and haw (BTW how to say that in G...Well, not to hem and haw (BTW how to say that in German?), then I am indeed saying, A) H&E are wrong to conclude that they can violate the uncertainty principle. Right, being able to closely measure position without "changing" momentum by some uncertainty, does not IMHO violate the HUP. IMHO the HUP is about intrinsic relations, not "changes" to something.<br /><br />Yet INeil Bateshttps://www.blogger.com/profile/04564859009749481136noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-65441180719658948182012-01-11T13:39:42.543-05:002012-01-11T13:39:42.543-05:00Bee,
Bell violation tests only show that after th...Bee,<br /><br />Bell violation tests only show that after the collapse of both wavefunctions, the states are correlated in a certain way. They do not require the entangled states to collapse in any particular order or timeframe. E&H's argument depends on when one considers the wavefunction to have collapsed. Depending on your choice of interpretation, wavefunction collapse may happen Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-68542926107537671262012-01-11T13:34:17.447-05:002012-01-11T13:34:17.447-05:00This comment has been removed by the author.Neil Bateshttps://www.blogger.com/profile/04564859009749481136noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-49464304003372407142012-01-11T12:44:40.627-05:002012-01-11T12:44:40.627-05:00This comment has been removed by the author.Neil Bateshttps://www.blogger.com/profile/04564859009749481136noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-47615626237900393162012-01-11T12:28:11.098-05:002012-01-11T12:28:11.098-05:00Here's larger Pic
Best,Here's larger <a href="http://2.bp.blogspot.com/_cldxKGOzgeM/SV4_1PdxVpI/AAAAAAAAB3g/Py4KCcBtSxE/s1600/25751201.jpg" rel="nofollow">Pic</a><br /><br />Best,PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-879628172518707352012-01-11T12:26:31.676-05:002012-01-11T12:26:31.676-05:00Bee, sorry such a clarity problem. I think it'...Bee, sorry such a clarity problem. I think it's better to say: no I don't think we can *violate* the HUP, but rather that H&E have misframed the nature of that issue. Remember there are basically two things we can say if to criticise someone:<br />1. The framed the issue correctly but are wrong<br />2. They misframed the issue, and so some variant of "not even wrong" (as theNeil Bateshttps://www.blogger.com/profile/04564859009749481136noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-7438382861305943022012-01-11T12:25:18.810-05:002012-01-11T12:25:18.810-05:00Hi Bee,
One thought experiment deserves another?:...Hi Bee,<br /><br />One thought experiment deserves another?:)<br /><br /><a href="http://2.bp.blogspot.com/_cldxKGOzgeM/SV4_1PdxVpI/AAAAAAAAB3g/Py4KCcBtSxE/s320/25751201.jpg" rel="nofollow">How to be in Two Places At Once</a><br /><br /><a href="http://www.scientificamerican.com/article.cfm?id=quantum-entanglement" rel="nofollow">Quantum Entanglement Benefits Exist after Links Are Broken</a> By PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-10814117333714369042012-01-11T08:46:11.757-05:002012-01-11T08:46:11.757-05:00They'd conclude it couldn't have happened ...They'd conclude it couldn't have happened within SR. So this guy sits there and monitors his wavefunctions and on occasion they make jumps (say from 1/2 to 1) and he reads out just the message that the other guy intended to send. Of course he doesn't actually know that until he has some way to verify that this was actually what the other guy was sending. Now, as I said, you could justSabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.com