tag:blogger.com,1999:blog-22973357.post8723570192134860394..comments2020-07-02T02:25:07.952-04:00Comments on Sabine Hossenfelder: Backreaction: Is COVID there before you measure it?Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger49125tag:blogger.com,1999:blog-22973357.post-78370762085591055902020-07-02T00:33:49.770-04:002020-07-02T00:33:49.770-04:00The likely reason he doesn't want to more test...The likely reason he doesn't want to more tests is that fewer positive cases will be reported by the media, yes, I think you understood that correctly. In case you missed the point, people die regardless of whether you know what they died from. <br /><br />In any case, the situation in the USA looks so bad at this point I suspect they'll soon give up testing people other than those who Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-83567190831124816322020-07-01T16:38:15.349-04:002020-07-01T16:38:15.349-04:00When we talk about Schrödinger’s cat, we should be...When we talk about Schrödinger’s cat, we should be aware of his motivation to create this thought experiment. It was not Schrödinger’s idea to give a lecture here about quantum mechanics. But his point was that he did not at all like the idea of superposition and he used this picture of a cat experiment to demonstrate how crazy he found this portion of quantum mechanics. antooneohttps://www.blogger.com/profile/12559038212417783694noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-8321192767614231402020-07-01T15:36:14.325-04:002020-07-01T15:36:14.325-04:00Sabine,
besides physics, how interesting do you f...Sabine,<br /><br />besides physics, how interesting do you find viruses?neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-62146365799740919942020-07-01T12:57:42.235-04:002020-07-01T12:57:42.235-04:00@ Greg Feild,
There's a theorem that the stan...@ Greg Feild,<br /><br />There's a theorem that the standard quantum logic cannot be embedded in a Boolean Logic. (Corollary of Gleason's Theorem or the Kochen-Specker theorem.) Since QT is empirically highly confirmed, it is reasonable to conclude the above!Prof. David Edwardshttps://www.blogger.com/profile/16079658994584920395noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-10083897570685249642020-07-01T12:49:41.640-04:002020-07-01T12:49:41.640-04:00I'm sorry that I didn't keep the reference...I'm sorry that I didn't keep the reference where I can find it, but some years ago I saw an article about a two-slit experiment run completely by computer, with no human observer involved in either detection, choice of whether to detect or not detect which slit a photon passed through, or analysis of results. In fact, the original observations were erased before any human had access to JimVhttps://www.blogger.com/profile/10198704789965278981noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-6284740857833883582020-07-01T11:57:28.143-04:002020-07-01T11:57:28.143-04:00"when Donald Trump claims that not testing pe..."when Donald Trump claims that not testing people for COVID means there will be fewer cases,"<br /><br />Is it not true there will be fewer _REPORTED_ cases? That's what virtually all news media report, even if it's not explicitly stated.<br />Epidemiologists will estimate & extrapolate the "number of infections", but majority of TV, web, and print reporters are TomHhttps://www.blogger.com/profile/13810033517103569254noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-26006845429123419902020-07-01T09:36:34.013-04:002020-07-01T09:36:34.013-04:00I quoted the blog post.I quoted the blog post.jim_hhttps://www.blogger.com/profile/10618326446656475641noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-3323766806748820392020-07-01T09:28:18.084-04:002020-07-01T09:28:18.084-04:00"measurement does not merely reveal a propert..."measurement does not merely reveal a property that previously existed, but that the act of measuring makes that property real."<br /><br />Can this statement be empirically confirmed? Isn't it just a prejudice?<br />Greg Feildhttps://www.blogger.com/profile/11893021846714172269noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-65044224592613294492020-07-01T09:19:16.970-04:002020-07-01T09:19:16.970-04:00Sabine asked: "Statistics of what do you thin...Sabine asked: "Statistics of what do you think [quantum theory] is?"<br /><br />Statistics of events, i.e. points in spacetime. Or in a higher-dimensional manifold. For example, in QED each event would not only be characterized by its space and time coordinates, but also by a phase factor (a la Kaluza-Klein). Fields describe correlations between events, and QFT is a machinery for Wernerhttps://www.blogger.com/profile/08502954437062856468noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-57610472052123181742020-07-01T01:15:31.014-04:002020-07-01T01:15:31.014-04:00Well then, Jim.
If we remove your term 'convi...Well then, Jim.<br /> If we remove your term 'convincingly ',<br /> and replace it with the<br />term. 'scientifically',<br /><br /> Then , no.<br /> It hasn't been proved.<br /> .<br /> My question is where did you come up with the term <br />' We Now understand 'A.C.https://www.blogger.com/profile/04994876510058676257noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-82509399920061223432020-07-01T01:13:50.481-04:002020-07-01T01:13:50.481-04:00Aleask,
That's just not correct. In the t->...Aleask,<br /><br />That's just not correct. In the t-> infinity limit you get the off-diagonal elements to strictly zero, but fapp you can't tell exactly zero from 10^-200 anyway, so you don't need t -> infinity. Decoherence is all well and fine, really. There's nothing wrong it it. It just does not solve the measurement problem, as too many people erroneously think. (ThoughSabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-23820082223905311392020-06-30T19:45:17.092-04:002020-06-30T19:45:17.092-04:00Sabine, what do you think of the following critiqu...Sabine, what do you think of the following critique (not mine, I think it's by Earman) of decoherence: it requires a limit in which time t must go to infinite in order to produce the desired result, which doesn't happen for any finite time, no matter how large. It's like the singularities in idealized situations like the Schwarzschild metric, you need more general theorems to prove aleazkhttps://www.blogger.com/profile/03359524052399645447noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-24964472967215043102020-06-30T19:35:36.848-04:002020-06-30T19:35:36.848-04:00"So when Donald Trump claims that not testing..."So when Donald Trump claims that not testing people for COVID means there will be fewer cases, rather than just fewer cases you know about, then that demonstrates his deep knowledge of quantum mechanics."<br /><br />Just GOLD. Love your sense of humor.aleazkhttps://www.blogger.com/profile/03359524052399645447noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-58498797884821546842020-06-30T17:03:26.364-04:002020-06-30T17:03:26.364-04:00Sabine,
The more I think the more I am sure that ...Sabine,<br /><br />The more I think the more I am sure that decoherence is just a neat - but very deceptive - way of sweeping the problem under the carpet. The problem is still alive and bites, as you seem to say in the last paragraph.<br /><br />,,The moon is there regardless of whether you look, and Schrödinger’s cat is either dead or alive regardless of whether you open the box, because the Wojciech Kryszakhttps://www.blogger.com/profile/02387687011580456850noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-59445576147009155572020-06-30T14:06:43.370-04:002020-06-30T14:06:43.370-04:00Prof. Edwards,
of course you can define "mea...Prof. Edwards,<br /><br />of course you can define "measurement" (or "perspective")<br />as "fundamental". Nice if it helps you to understand quantum theory better. For me it has the opposite effect.Wernerhttps://www.blogger.com/profile/08502954437062856468noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-73947132523733013052020-06-30T09:49:34.016-04:002020-06-30T09:49:34.016-04:00Bohr and von Neumann, eh? Well good for you, at le...Bohr and von Neumann, eh? Well good for you, at least it's less tired than the kinship claims to Galileo, Einstein and Feynman.DougOnBloggerhttps://www.blogger.com/profile/16411970226629138387noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-43689086506021562142020-06-30T09:40:53.397-04:002020-06-30T09:40:53.397-04:00"... we now understand that it is irrelevant ..."... we now understand that it is irrelevant whether a person does the observation in quantum mechanics. It could as well be an apparatus."<br /><br />When, and how, has this been convincingly shown to be true?jim_hhttps://www.blogger.com/profile/10618326446656475641noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-22346129548903304032020-06-30T09:38:32.015-04:002020-06-30T09:38:32.015-04:00@ Werner,
You write:
"If you believe that q...@ Werner,<br /><br />You write:<br /><br />"If you believe that quantum mechanics is about "measurements", then it cannot be a fundamental theory."<br /><br />This depends upon a metaphysical assumption prioritizing physicalism over perspectivism! But Quantum Theory is best understood as a form of perspectivism not physicalism.<br />Prof. David Edwardshttps://www.blogger.com/profile/16079658994584920395noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-67694003924204813212020-06-30T09:23:30.800-04:002020-06-30T09:23:30.800-04:00"Why is it so difficult to accept quantum the...<i>"Why is it so difficult to accept quantum theory as the statistical theory that it obviously is?"</i><br /><br />Statistics of what do you think it is? Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-69196550964477278582020-06-30T08:26:19.948-04:002020-06-30T08:26:19.948-04:00Quantum gravitation in the UV limit is in a funny ...Quantum gravitation in the UV limit is in a funny way "self-decohering," and is then not quantum in the standard meaning of the term. See above with my comment to Castaldo ( Dr. A.M. Castaldo1:56 PM, June 29, 2020 ) about some of this. Gravitation is no unitary in the usual meaning because as a gauge-like theory it is not Lorentzian. By some means quantum gravitation is a quantum error Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-20096274380950540982020-06-30T08:21:00.131-04:002020-06-30T08:21:00.131-04:00Gravitons can have different wavelengths and thus ...Gravitons can have different wavelengths and thus different energy. The low energy weak interacting gravitons are approximately linear and may form superpositions more readily. High energy gravitons may not. Curvature in a cryptic representation are R ~ ∇Γ + ΓΓ, where the dependency on constants is Γ ~ G/c^2, and Γ varies with energy or momentum as E^2 or p^2, which means terms quadratic in Γ or Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-12182263505087023962020-06-30T05:47:17.304-04:002020-06-30T05:47:17.304-04:00Sabine wrote: "In quantum mechanics, the act ...Sabine wrote: "In quantum mechanics, the act of observation has special relevance."<br /><br />Why should anybody accept this? If you believe that quantum mechanics is about "measurements", then it cannot be a fundamental theory. John Bell wrote:<br /><br />"And does not any <b>analysis</b> of measurement require concepts more <b>fundamental</b> than measurement? And Wernerhttps://www.blogger.com/profile/08502954437062856468noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-39010188856864119412020-06-29T19:25:02.458-04:002020-06-29T19:25:02.458-04:00well, Wolves can cooperate to pull on 2 separate r...well, Wolves can cooperate to pull on 2 separate ropes simultaneously, to pull a tray of food toward themselves.<br />https://www.nytimes.com/2017/11/07/science/wolves-dogs-cooperation.html<br />Unclear whether that implies any spatial reasoning. Perhaps it's no different than 4 wolves instinctively pulling at 4 legs of their prey, to tear apart the hapless victim.TomHhttps://www.blogger.com/profile/13810033517103569254noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-45264396926291938482020-06-29T13:56:07.040-04:002020-06-29T13:56:07.040-04:00I'm not a physicist, but I like the idea that ...I'm not a physicist, but I like the idea that if gravity is quantized, there is a minimum unit of gravity. Maybe superposition spontaneously collapses if the superposed gravitational fields differ by more than a gravitational unit; i.e. there is only so much "gravitational strain" that superposition can support.<br /><br />Dr. A.M. Castaldohttps://www.blogger.com/profile/17988116835722393503noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-21348194696695879062020-06-29T10:20:22.205-04:002020-06-29T10:20:22.205-04:00I think even short of full quantum gravity, there ...I think even short of full quantum gravity, there are some interesting things we can wonder about it. My understanding was that there's an interesting question on whether or not, once we can get the coldness and noise under control to get a system of order Plank mass into a coherent quantum state, its gravitation would cause it to decohere. Though I'm fuzzy on the specifics of what we'DougOnBloggerhttps://www.blogger.com/profile/16411970226629138387noreply@blogger.com