tag:blogger.com,1999:blog-7315236707728759521.comments2024-03-28T21:52:52.100-06:00Dispatches From Turtle IslandAndrew Oh-Willekehttp://www.blogger.com/profile/02537151821869153861noreply@blogger.comBlogger5328125tag:blogger.com,1999:blog-7315236707728759521.post-32066628620558062472024-03-28T21:52:52.100-06:002024-03-28T21:52:52.100-06:00different computer simulation might have differen...different computer simulation might have different results neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-75813905178193134132024-03-28T19:02:22.210-06:002024-03-28T19:02:22.210-06:00Hum... as a software developer for 40+ years I can...Hum... as a software developer for 40+ years I can say with confidence that there are no bugs in their code. Just features.Guyhttps://www.blogger.com/profile/15789570230699865921noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-59504992317537946842024-03-27T22:28:06.861-06:002024-03-27T22:28:06.861-06:00With the employment of the genetic algorithm and a...With the employment of the genetic algorithm and a Markov-Chain Monte-Carlo method,<br /><br />computer simulation <br /><br />neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-16772777611359174362024-03-25T18:19:28.298-06:002024-03-25T18:19:28.298-06:00Sorry, I was premature to mention it on your site ...Sorry, I was premature to mention it on your site in that the paper, which encompasses a range of topics, is just a Microsoft word file, and not yet posted anywhere. The paper(s), only dealing with the weak interactions, written about 1993-1994 are complete, but have some inconsistencies and problems that will be addressed in the multi-topic paper that incorporates the modification in the weak interaction section. Three of 12 sections, in this paper are in need of completion. These "sections" range from a single paragraph to several pages. To be honest my paper is semi-amateur, and I'll leave it to people with much greater knowledge and certainly higher IQ's than I have to decide if it has any ultimate value. I'm currently trying to understand spinors at a level where I can (hopefully) make a deep connection between the ideas in this paper and the Standard Model. David Schroederhttps://www.blogger.com/profile/18048116250413347228noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-14000852822047465392024-03-25T09:31:14.035-06:002024-03-25T09:31:14.035-06:00@DavidSchroeder
I'd be interested in reading ...@DavidSchroeder<br /><br />I'd be interested in reading it. Please post a link when you post something.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-48623270764346629512024-03-23T13:45:05.226-06:002024-03-23T13:45:05.226-06:00I found that fresh fruit and spinach salads seemed...I found that fresh fruit and spinach salads seemed to boost my energy levels, even though I am in the slightly pre-Boomer age bracket. Hopefully that will work for you as well. Now I was just reading a post of yours from July 19, 2012 titled: "Koide's Formula and Running Fermion Masses". I was drawn to the post while looking up CP violation in the weak interactions. Back in the 90's I hit upon a simple idea to explain why there are three and only three generations of quarks and leptons, and submitted the paper to various venues - Scientific American, Il Nuovo Cimento, and others. All declined to publish, which didn't surprise me, as it was quite speculative, among other things. But just recently a modification of that idea, which would handily explain Parity and CP violation in a more direct manner than the original idea, occurred to me. It also might explain (via a direct physical mechanism) why physicists apparently prefer to use the complex-valued pole mass for unstable particle masses. It's wildly speculative, but I'll post this new iteration of an old idea on viXra, when its finished. David Schroederhttps://www.blogger.com/profile/18048116250413347228noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-27523428851888776592024-03-22T19:43:06.288-06:002024-03-22T19:43:06.288-06:00I know you are the biggest fan of Deur for MOND,
...I know you are the biggest fan of Deur for MOND,<br /><br />but there are now 3 recent papers that purport to get MOND from GR, that isn't self-interaction, which was met at PF with intense skepticism. all in 2024, maybe if you combine all 3 you get MOND from GR, <br /><br />and also since MOND doesn't explain galaxy clusters, or third peak of CMB, there are 2 recent papers that show PBH could be dark matter since hawking radiation changes and asteroid mass PBH isn't ruled out <br /><br /><br />arXiv:2403.13019 (gr-qc)<br />[Submitted on 18 Mar 2024]<br />Many body gravity and the galaxy rotation curves<br />S Ganesh<br /><br /> A novel theory was proposed earlier to model systems with thermal gradients, based on the postulate that the spatial and temporal variation in temperature can be recast as a variation in the metric. Combining the variation in the metric due to the thermal variations and gravity, leads to the concept of thermal gravity in a 5-D space-time-temperature setting. When the 5-D Einstein field equations are projected to a 4-D space, they result in additional terms in the field equations. This may lead to unique phenomena such as the spontaneous symmetry breaking of scalar particles in the presence of a strong gravitational field. This theory, originally conceived in a quantum mechanical framework, is now adapted to explain the galaxy rotation curves. A galaxy is not in a state of thermal equilibrium. A parameter called the "degree of thermalization" is introduced to model partially thermalized systems. The generalization of thermal gravity to partially thermalized systems, leads to the theory of many-body gravity. The theory of many-body gravity is now shown to be able to explain the rotation curves of the Milky Way and the M31 (Andromeda) galaxies, to a fair extent. The radial acceleration relation (RAR) for 21 galaxies, with variations spanning three orders of magnitude in galactic mass, is also reproduced. <br /><br />Comments: 13 pages, 6 figures<br />Subjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics of Galaxies (astro-ph.GA); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th); Mathematical Physics (math-ph)<br />Cite as: arXiv:2403.13019 [gr-qc]neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-92128665455344599522024-03-22T10:31:26.510-06:002024-03-22T10:31:26.510-06:00DDeden and neo. Thanks for pointing out these poin...DDeden and neo. Thanks for pointing out these points. It will be good to have a backlog of things to write about when I have enough energy.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-66739306929986044802024-03-22T09:47:21.131-06:002024-03-22T09:47:21.131-06:00arXiv:2403.14309 [pdf, other]
Probing modified...arXiv:2403.14309 [pdf, other]<br /> Probing modified Hawking evaporation with gravitational waves from the primordial black hole dominated universe<br /> Shyam Balaji, Guillem Domènech, Gabriele Franciolini, Alexander Ganz, Jan Tränkle<br /> Comments: 18 pages+appendices, 7 figures<br /> Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)<br /><br /> It has been recently proposed that Hawking evaporation might slow down after a black hole has lost about half of its mass. Such an effect, called "memory burden", is parameterized as a suppression in the mass loss rate by negative powers n of the black hole entropy and could considerably extend the lifetime of a black hole. We study the impact of memory burden on the Primordial Black Hole (PBH) reheating scenario. Modified PBH evaporation leads to a significantly longer PBH dominated stage. Requiring that PBHs evaporate prior enough to Big Bang Nucleosynthesis shrinks the allowed PBH mass range. Indeed, we find that for n>2.5 the PBH reheating scenario is not viable. The frequency of the Gravitational Waves (GWs) induced by PBH number density fluctuations is bound to be larger than about a Hz, while the amplitude of the GW spectrum is enhanced due to the longer PBH dominated phase. Interestingly, we show that, in some models, the slope of the induced GW spectrum might be sensitive to the modifications to Hawking evaporation, proving it may be possible to test the "memory burden" effect via induced GWs. Lastly, we argue that our results could also apply to general modifications of Hawking evaporation.<br />neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-50649708700001389032024-03-21T04:54:21.710-06:002024-03-21T04:54:21.710-06:00In addition to the Polynesian crops, the researche...In addition to the Polynesian crops, the researchers found three species of South American starchy foods: achira, sweet potato and cassava. In particular, "the identification of sweet potato starch grains in the lower levels of the Anakena site suggests an introduction of this species to Rapa Nui during the earliest settlement period," the researchers wrote. Cassava also seems to have been present on Rapa Nui long before European explorers visited its shores.<br /><br />https://www.livescience.com/archaeology/obsidian-blades-with-food-traces-reveal-1st-settlers-of-rapa-nui-had-regular-contact-with-south-americans-1000-years-agoDDedenhttps://www.blogger.com/profile/10033851770461086341noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-15213917838101770092024-03-21T00:41:14.454-06:002024-03-21T00:41:14.454-06:00Rest wellRest wellMitchellhttps://www.blogger.com/profile/10768655514143252049noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-9176507436922375492024-03-20T11:20:49.571-06:002024-03-20T11:20:49.571-06:00@Guy
Conservation of information is one way to ge...@Guy<br /><br />Conservation of information is one way to get there, but Hawking radiation is a concept that doesn't inherently rely on conservation of information. The basic concept behind Hawking radiation is that the pair production and destruction associated with sea quarks in hadrons happens on either side of an event horizon of a black hole with a predictable and calculable frequency, with half of the produced pair within it and half of the produced pair escaping the black hole. This can be derived from conservation of mass-energy and CPT and lepton number and baryon number which are very well demonstrated in other contexts, without an information conservation condition that is more speculative.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-36736641770442743212024-03-17T09:50:18.811-06:002024-03-17T09:50:18.811-06:00Hum... That Hawking Evaporation paper (and the pap...Hum... That Hawking Evaporation paper (and the papers they reference) are based on the assumption that information can not be destroyed. If you assume that information can be permanently lost in a BH then that constraint goes away. Obviously that would blow a lot of modern physics out of the ballpark, but as has been observed by many theorists, nature is not constrained to be simple and to match our simple theories.Guyhttps://www.blogger.com/profile/15789570230699865921noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-67178948491845691592024-03-15T16:13:08.397-06:002024-03-15T16:13:08.397-06:00@ andrew
"Hawking radiation is a quick and ...<br />@ andrew <br /><br />"Hawking radiation is a quick and easy way to eliminate light PBH matter as a DM candidate. So, there hasn't been a lot written on other constraints on it.<br /><br />the paper is written on other constraints on it<br /><br />from the abstract <br /><br /><br />arXiv:2402.17823 (astro-ph)<br />[Submitted on 27 Feb 2024]<br />Breakdown of Hawking Evaporation opens new Mass Window for Primordial Black Holes as Dark Matter Candidate<br />Valentin Thoss, Andreas Burkert, Kazunori Kohri<br />"However, Hawking's semiclassical approximation breaks down at latest after half-decay. Beyond this point, the evaporation could be significantly suppressed as was shown in recent work. "<br /><br /> "But, for example, any DM candidate really needs to be 10 keV or less so that its behavior can be "wave-like" as observations require."<br /><br />that papers assume Newtonian gravity neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-85606413306321747482024-03-15T13:01:07.734-06:002024-03-15T13:01:07.734-06:00@neo
"Primordial black holes (PBHs) can make...@neo<br /><br />"Primordial black holes (PBHs) can make up all of the dark matter (DM) if their mass, m, is in the so-called 'asteroid-mass window', 1017g≲m≲1022g."<br /><br />Solar system orbits of various kinds of planets and asteroids rule out the asteroid window.<br /><br />"The energy injection through Hawking evaporation has been used to put strong constraints on primordial black holes as a dark matter candidate at masses below 1017g. However, Hawking's semiclassical approximation breaks down at latest after half-decay. Beyond this point, the evaporation could be significantly suppressed as was shown in recent work. In this study, we review existing cosmological and astrophysical bounds on primordial black holes taking this effect into account. We show that the constraints disappear completely for a reasonable range of parameters, which opens a new window below 1010g for light primordial black holes as a dark matter candidate."<br /><br />Hawking radiation is a quick and easy way to eliminate light PBH matter as a DM candidate. So, there hasn't been a lot written on other constraints on it. But, for example, any DM candidate really needs to be 10 keV or less so that its behavior can be "wave-like" as observations require.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-5844761846059579792024-03-14T15:16:44.345-06:002024-03-14T15:16:44.345-06:00Best wishes Andrew, hope you recover quickly. I wa...Best wishes Andrew, hope you recover quickly. I was hit by two months of lethargy after my own covisd illness about a year ago. Take it easy for a while.Graham Dungworthhttps://www.blogger.com/profile/18355209024912564624noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-43158002074669116052024-03-14T11:26:00.758-06:002024-03-14T11:26:00.758-06:00Dark Matter Is Not Made Up Of Primordial Black Hol...Dark Matter Is Not Made Up Of Primordial Black Holes<br /><br />any comment on <br /><br />arXiv:2403.03839 (astro-ph)<br />[Submitted on 6 Mar 2024]<br />How open is the asteroid-mass primordial black hole window?<br />Matthew Gorton, Anne M. Green<br /><br />Primordial black holes (PBHs) can make up all of the dark matter (DM) if their mass, m, is in the so-called 'asteroid-mass window', 1017g≲m≲1022g.<br /><br />arXiv:2402.17823 (astro-ph)<br />[Submitted on 27 Feb 2024]<br />Breakdown of Hawking Evaporation opens new Mass Window for Primordial Black Holes as Dark Matter Candidate<br />Valentin Thoss, Andreas Burkert, Kazunori Kohri<br /><br />The energy injection through Hawking evaporation has been used to put strong constraints on primordial black holes as a dark matter candidate at masses below 1017g. However, Hawking's semiclassical approximation breaks down at latest after half-decay. Beyond this point, the evaporation could be significantly suppressed as was shown in recent work. In this study, we review existing cosmological and astrophysical bounds on primordial black holes taking this effect into account. We show that the constraints disappear completely for a reasonable range of parameters, which opens a new window below 1010g for light primordial black holes as a dark matter candidate. neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-17337536846564627482024-03-13T05:37:40.832-06:002024-03-13T05:37:40.832-06:00Hi Andrew, Thanx for information and all the refer...Hi Andrew, Thanx for information and all the references!Guyhttps://www.blogger.com/profile/15789570230699865921noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-57457388819972407562024-03-13T03:25:06.101-06:002024-03-13T03:25:06.101-06:00@neo
Thanks for the heads up.
@all
FYI, there ...@neo <br /><br />Thanks for the heads up.<br /><br />@all<br /><br />FYI, there haven't been many posts or long comments at this blog for a while because I was in Las Vegas for four days to support a team of six runners in their half marathon and then got COVID on the way home and was very sick for about a week and a half (and I am still not 100%).andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-46462419467131006592024-03-13T01:13:11.443-06:002024-03-13T01:13:11.443-06:00
sabine
http://backreaction.blogspot.com/
revie...<br />sabine <br /><br />http://backreaction.blogspot.com/<br /><br />reviews <br /><br />arXiv:2402.19459 [pdf, other]Anomalous contribution to galactic rotation curves due to stochastic spacetimeJonathan Oppenheim, Andrea RussoSubjects<br /><br />Tuesday, March 12, 2024<br />Three Physics Mysteries Solved At Once: Postquantum Gravity<br />For the first time in 4 decades, physicists have found a new approach to solving a problem which is almost a century old: How to combine quantum physics with gravity. I told you about this new approach, called “Postquantum Gravity” from Johnathan Oppenheim briefly before Christmas. He and his collaborators are now saying that their idea also explains dark matter and dark energy. <br /><br /><br />another GR MOND besides Deur neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-55658514798251658492024-03-12T22:14:25.883-06:002024-03-12T22:14:25.883-06:00"Is this a rest energy thing where 2u1d is th..."Is this a rest energy thing where 2u1d is the lowest energy internal state, or are there always "many" quarks in the proton."<br /><br />There are always many quarks in the proton, and the reason that they tell the "lies to children" version with 2u1d is that all of the observable properties of the proton can be derived from knowing there are the 2u and 1d valence quarks. All other quarks in the proton come in quark-antiquark pairs and wash out.<br /><br />The best analogy to how we know about sea quarks that I've seen is the xkcd "fruit collider" comic that illustrates just how profoundly weird it is that there is so much more than the valence quarks in a proton or other hadron. See https://xkcd.com/1949/<br /><br />A closely related concept is the Proton Spin Crisis. https://en.wikipedia.org/wiki/Proton_spin_crisis<br /><br />The deal with this is that in every hadron, the total angular momentum (i.e. "spin") of the composite hadron as a whole is always a function of the sum of the spin of its valence quarks (which each can be plus or minus relative to each other). But, mysteriously, when you actually dig around inside a proton (or other hadron) looking for the sources of angular momentum in that composite particle that adds up to the sum of the spins of its valence quarks, this isn't where the angular momentum is actually located in the particles making up the proton. Some of its in the gluons, some of it is in the sea quarks, and far less than 100% of the total is in the valence quarks themselves. We really have no clue why this is so.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-3146406803602104002024-03-12T22:03:49.888-06:002024-03-12T22:03:49.888-06:00The two ups and a down you heard about are called ...The two ups and a down you heard about are called "valence quarks" and the others are called "sea quarks". <br /><br />Strassler's web page discussion on the topic is actually very solid and understandable. See https://profmattstrassler.com/articles-and-posts/particle-physics-basics/the-structure-of-matter/protons-and-neutrons/<br /><br />The technical description of the sea quarks of a hadron like a proton or a neutron is called its "parton distribution function" (or PDF for short).https://en.wikipedia.org/wiki/Parton_(particle_physics) An 83 page scientific journal paper from the year 2000 is a good review article on the subject. https://www.osti.gov/servlets/purl/799541<br /><br />In principle you can calculate a PDF from the equations and physical constants of the Standard Model of Particle Physics, but it is wickedly hard to do the calculations, so until maybe 4-5 years ago, these were compiled by just collecting data from gillions of collisions and fitting it to algebraic functions. See https://dispatchesfromturtleisland.blogspot.com/2020/05/progress-in-calculating-pdfs-from-first.html<br /><br />Also, your statement that "the total number of up and down quarks and anti quarks in a proton is not constant" is true, but misleading, because it conceals one of the key relevant rules which is "conservation of baryon number", which holds that the total number of quarks minus the total number antiquarks in any system remains constant. https://en.wikipedia.org/wiki/Baryon_number<br /><br />In all of history, there has never been an observed instance of conservation of baryon number being violated, although there is one process call the sphaleron interaction in the Standard Model of Particle Physics in which baryon number violation is theoretically possible at energies about 100 times as great as the Large Hadron Collider (the most powerful particle collider of all time). See generally, these posts at this blog: https://dispatchesfromturtleisland.blogspot.com/search?q=sphaleronandrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-1964703155552868552024-03-12T21:02:40.101-06:002024-03-12T21:02:40.101-06:00Bantu is the second largest language in South Suda...Bantu is the second largest language in South Sudan. Kisra is a flatbread of Sudan made from ground sorghum flour. https://en.m.wikipedia.org/wiki/Kisra#:~:text=%22Kisra:%20A%20Traditional%20Fermented%20Flatbread,and%20Nutritional%20and%20Therapeutic%20Aspects.DDedenhttps://www.blogger.com/profile/10033851770461086341noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-22876196740937085972024-03-12T20:44:24.488-06:002024-03-12T20:44:24.488-06:00Per etymology online, 'shampoo' may derive...Per etymology online, 'shampoo' may derive from Sanskrit chapayati : pound, knead. Indian flatbread is chapati. Somewhat similar to "pita" & "pita-ru".<br /><br />1762, "to massage, rub and percuss the surface of (the body) to restore tone and vigor," from Anglo-Indian shampoo, from Hindi champo, imperative of champna "to press, knead the muscles," perhaps from Sanskrit capayati "pounds, kneads." The thing is thoroughly described in "A Voyage to the East Indies" (1762DDedenhttps://www.blogger.com/profile/10033851770461086341noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-82663770266786221652024-03-11T18:16:25.306-06:002024-03-11T18:16:25.306-06:00Hi Andrew,
I need some help here. I'm reading ...Hi Andrew,<br />I need some help here. I'm reading Strassler's new book "Waves in an Impossible Sea". In chapter 6.4 he discusses the apparently well known fact that the total number of up and down quarks and anti quarks in a proton is not constant. Where as I was taught, back in the stone age, that a proton had two ups and a down. Which he lists as a constraint, that there are always three unpaired quarks (2u1d). Is this a rest energy thing where 2u1d is the lowest energy internal state, or are there always "many" quarks in the proton.<br /><br />In addition what would a good place to start reading about this, or the correct search string to find papers?<br /><br />Cheers,<br />GuyGuyhttps://www.blogger.com/profile/15789570230699865921noreply@blogger.com