tag:blogger.com,1999:blog-22973357.post806314004306414422..comments2020-10-29T13:20:47.362-04:00Comments on Sabine Hossenfelder: Backreaction: Understanding Quantum Mechanics #6: It’s not just a theory for small things.Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger48125tag:blogger.com,1999:blog-22973357.post-39548945247767615422020-10-23T07:01:52.690-04:002020-10-23T07:01:52.690-04:00Hi Sabine, can wave function collapse be seen as a...Hi Sabine, can wave function collapse be seen as a symmetry breaking, a symmetry that translates into conservation of behavior (or logical consistency given by some axioms)? This symmetry would conserve the probabilistic behavior and interference (quantum behavior) and when it breaks down we remain with particles and general relativity.Catalin Tudorhttps://www.blogger.com/profile/06192244112905762189noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-54410766939193622292020-10-07T07:50:14.130-04:002020-10-07T07:50:14.130-04:00Andrei:
Sorry, I have at first overlooked your qu...Andrei:<br /><br />Sorry, I have at first overlooked your question. <br /><br />De Broglie first described his electron model in his thesis for which he received the Nobel prize:<br /> <br />'Recherches sur la théorie des quanta (Researches on the quantum theory), Thesis, Paris, 1924, Ann. de Physique (10) 3, 22 (1925)'<br />An English translation of the paper by A. F. Kracklauer can be antooneohttps://www.blogger.com/profile/12559038212417783694noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-56643095706971540822020-10-06T09:46:25.764-04:002020-10-06T09:46:25.764-04:00Antooneo said on 5:07 PM, September 28, 2020
“Now...Antooneo said on 5:07 PM, September 28, 2020<br /><br />“Now, with this knowledge, it is possible to understand the phenomenon, even without QM. It's not really complicated. But then the question, why not radiating in an atomic orbit, is more complicated.”<br /><br />Indeed, this is a situation where the QM rationale for the lack of radiative loss in an atom always seemed to be incomplete to David Schroederhttps://www.blogger.com/profile/18048116250413347228noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-15635149148166034212020-10-06T06:40:30.985-04:002020-10-06T06:40:30.985-04:00Playing with high temperature superconductors, in ...Playing with high temperature superconductors, in recent years, it was always quite cool to observe the macroscopic quantum effect of flux pinning as a small neodymium magnet hovered above the YBCO chip immersed in liquid nitrogen.David Schroederhttps://www.blogger.com/profile/18048116250413347228noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-55677885226900401732020-10-06T03:34:33.459-04:002020-10-06T03:34:33.459-04:00All rough-levels of statistics of physics are emer...All rough-levels of statistics of physics are emergencies of statistical behavior of quanta, ok?Eusahttps://www.blogger.com/profile/14114706429392111062noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-56977566293895646342020-10-05T17:00:47.840-04:002020-10-05T17:00:47.840-04:00The surface of a material has a sort of quantum at...The surface of a material has a sort of quantum atmosphere. The quantum fields or states that compose a substance define a quantum wave region within around 10^{-8}cm or so. As a result the electron approaching the material of the mask destructively interferes with this wavy quantum atmosphere. Frank Wilczek wrote a paper on the quantum atmosphere a couple of years ago.Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-73756289417765364292020-10-05T04:14:52.430-04:002020-10-05T04:14:52.430-04:00Lawrence Crowell,
" You would have to use, b...Lawrence Crowell,<br /><br />" You would have to use, but some unknown means, material in a neutron star to do a 2-slit experiment with neutrinos."<br /><br />Sure, but my point was that it is a requirement for this experiment to work that the incoming particles interact with the barrier. If they do not interact with it (like in the case of neutrinos passing through a copper foil) no Andreihttps://www.blogger.com/profile/05519448415253342448noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-73568615339271766972020-10-03T22:36:18.507-04:002020-10-03T22:36:18.507-04:00I feel I agree, but it's quite significant tha...I feel I agree, but it's quite significant that it can't simply statistics covering up our ignorance of something better behaved. There's a lot of statistics in the world but this is special.DougOnBloggerhttps://www.blogger.com/profile/16411970226629138387noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-62659200331157825302020-10-03T09:56:38.122-04:002020-10-03T09:56:38.122-04:00Hi, Sabine! I just wanted to say that your videos ...Hi, Sabine! I just wanted to say that your videos (specially the one about bra-ket notation) and Matt's PBS space time channel took away my fear to dive deeper into the math of QM. It motivated me to watch the 10 lecture course from susskind and the plan now is to start the 3º feynman book.<br /><br />Thanks for all your work. You are a great educator.Viniciushttps://www.blogger.com/profile/13850818401542524952noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-2405238858002907252020-10-03T08:37:15.476-04:002020-10-03T08:37:15.476-04:00The 2-slit experiment works for a range of particl...The 2-slit experiment works for a range of particles, the easiest being photons and it has been done with neutrons. If this were done with neutrinos there would be no interference pattern for neutrinos pass through most ordinary matter. You would have to use, but some unknown means, material in a neutron star to do a 2-slit experiment with neutrinos. The fact this matter in the slit interacts is Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-29877626543543545602020-10-03T03:30:39.400-04:002020-10-03T03:30:39.400-04:00In my opinion, the most obvious topic in quantum m...In my opinion, the most obvious topic in quantum mechanics is that it is purely a statistical theory. You can’t get the right results with enough accuracy without extensively comprehensive statistics, which usually mean macroscopic structures.Eusahttps://www.blogger.com/profile/14114706429392111062noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-79273377788012143932020-10-02T12:32:17.601-04:002020-10-02T12:32:17.601-04:00Stefan Freundt,
Why so complicated? Your problems...Stefan Freundt,<br /><br />Why so complicated? Your problems do not exist if we follow the model of de Broglie. The field which guides the electron is an alternating field. (Classically understandable as the electron rotates and so do its internal charges.) This field underlies of course also destructive interference which explains the minima.<br />De Broglie has assumed that there is no antooneohttps://www.blogger.com/profile/12559038212417783694noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-40164913633273184812020-10-02T08:32:20.169-04:002020-10-02T08:32:20.169-04:00Lawrence Crowell,
1. No matter how small the fiel...Lawrence Crowell,<br /><br />1. No matter how small the field is it has to be the cause of the electron's change in trajectory because there is nothing else that could do it. Gravity is even weaker.<br /><br />2. How strong the field needs to be so that it accounts for the change in electron's trajectory?<br /><br />3. Charged particles in a solid do not move at random, independently of Andreihttps://www.blogger.com/profile/05519448415253342448noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-2383637092050621782020-10-02T05:35:43.765-04:002020-10-02T05:35:43.765-04:00Assume there are equal number of positive and nega...Assume there are equal number of positive and negative charges spaced around in a region with a mutual distance from each other around d. For a distance r >> d the electric field is going to appear as E ~ qd^{n-1}/r^{n+1}, which if n is very large is a very small field.Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-16855153469459050492020-10-02T04:29:30.726-04:002020-10-02T04:29:30.726-04:00antooneo,
de Broglie's theory is non-local, r...antooneo,<br /><br />de Broglie's theory is non-local, right? Can you point me to the paper where the electron model of Louis de Broglie is presented?Andreihttps://www.blogger.com/profile/05519448415253342448noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-974729288196630382020-10-02T03:51:14.441-04:002020-10-02T03:51:14.441-04:00Stefan Freundt,
"the negative and positive c...Stefan Freundt,<br /><br />"the negative and positive charges neutralize each other."<br /><br />No, they do not. The electrons and nuclei do not share the same position, therefore it will be a field. An electric dipole, even if "neutral" does produce an electromagnetic field of infinite range.<br /><br />"Correspondingly, there is no electric field and thus no deflectionAndreihttps://www.blogger.com/profile/05519448415253342448noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-31090034498996427222020-10-01T16:18:08.710-04:002020-10-01T16:18:08.710-04:00Hello Andrei,
the negative and positive charges n...Hello Andrei,<br /><br />the negative and positive charges neutralize each other.<br />Correspondingly, there is no electric field and thus no deflection.<br />There will be no paper.<br />Do you expect an electrically neutral object to deflect an electron?<br /><br />But well.<br />Let us assume for the moment that the electron - as a particle - flies through the right slit.<br />Does the left Stefan Freundthttps://www.blogger.com/profile/04834262116439292657noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-56814407943291051532020-10-01T14:30:03.645-04:002020-10-01T14:30:03.645-04:00@Prof. David Edwards:
I have mentioned Richard Fe...@Prof. David Edwards:<br /><br />I have mentioned Richard Feynman because he says in the lecture that there is a theory of QED on the one hand but on the other hand there is no justification for this theory – which I find typical for QM. You say that there is a further development of bits and pieces of the theory; thank you.<br /><br />@Andrei9 and Stefan Freundt:<br /><br />If we take the antooneohttps://www.blogger.com/profile/12559038212417783694noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-30885100950342511632020-10-01T13:04:37.576-04:002020-10-01T13:04:37.576-04:00Stefan Freundt,
"Whether the second slit is ...Stefan Freundt,<br /><br />"Whether the second slit is there or not is negligible for the particles."<br /><br />Can you point me to a paper where the fields are computed and found negligible in regards to electron's trajectory?Andreihttps://www.blogger.com/profile/05519448415253342448noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-72471440092639150702020-10-01T12:32:45.873-04:002020-10-01T12:32:45.873-04:00I am saying that one can not do an experiment to l...I am saying that one can not do an experiment to localize a quantum bit on a smaller scale than ℓ_p. I am not saying this is some minimal length, which is what the LQG tend or tended to impose. A string has an infinite set of modes, and most of these waves have wavelength below the Planck scale. If an experimenter tries to localize a qubit on a smaller scale this requires a Planck energy or more Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-60036988894065155022020-10-01T11:09:55.427-04:002020-10-01T11:09:55.427-04:00Hello Andrei,
but in this picture you will not see...Hello Andrei,<br />but in this picture you will not see any interference stripes, but only the classic two stripes, one behind each slit. The particles then behave like shot balls. Whether the second slit is there or not is negligible for the particles.<br />Have Fun<br />StefanStefan Freundthttps://www.blogger.com/profile/04834262116439292657noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-38240943669840783122020-10-01T09:15:12.156-04:002020-10-01T09:15:12.156-04:00"This is a physical real quantity that gives ...<i>"This is a physical real quantity that gives a natural scale for QFT cut-off, which is applicable to quantum gravitation. The scale means this is the smallest region one can localize a qubit. "</i><br /><br />This is incorrect. The former is a distance *scale* (correct) the latter is a distance (incorrect). The former is Lorentz-invariant, the latter Lorentz-covariant, meaning it Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-54349415111504049892020-10-01T09:09:56.352-04:002020-10-01T09:09:56.352-04:00Stefan Freundt,
"What we can exclude are:
- ...Stefan Freundt,<br /><br />"What we can exclude are:<br />- particles, because they cannot see both slits."<br /><br />Of course they can. The concept is well known in classical physics and it is called "field". An electron can "see" both slits because the barrier consists on charged particles (electrons and nuclei) and the field configuration depends on the Andreihttps://www.blogger.com/profile/05519448415253342448noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-21169514347970030242020-10-01T06:29:31.209-04:002020-10-01T06:29:31.209-04:00That is not right. The Planck length can be derive...That is not right. The Planck length can be derived by setting the wavelength of a black hole equal to its Schwarzschild radius. Another way is to think of a black hole changing its mass and Schwarzschild radius 2GM/c^2 by absorbing a particle of mass m. This particle has a Compton wavelength λ = ħ/mc. Since any particle entering a black hole or leaving by Hawking radiation gives no information Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-85633898319636997612020-10-01T00:52:04.514-04:002020-10-01T00:52:04.514-04:00Hello Antooneo,
construct an object that
- is lar...Hello Antooneo,<br /><br />construct an object that<br />- is larger than a double slit<br />- is able to fly through it<br />- is absorbed from time to time<br />- comes through from time to time and then is still essentially the same object<br />What we can exclude are:<br />- particles, because they cannot see both slits.<br />- waves, there is no object that contracts waves again, which is Stefan Freundthttps://www.blogger.com/profile/04834262116439292657noreply@blogger.com