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Researchers have discovered magnetic monopole quasi-particles
- empath-nirvana 3y agoIt's a quasi-particle that's a monopole, and I think they've found quasi-particles that behaved as monopoles before if I'm not mistaken? In more exotic materials than hematite, though, I think.
- jerf 3y agoWikipedia discusses a number of such particles: https://en.wikipedia.org/wiki/Magnetic_monopole#%22Monopoles%22_in_condensed-matter_systems https://en.wikipedia.org/wiki/Magnetic_monopole#%22Monopoles...
- eesmith 3y agoYes. For example, https://www.nature.com/articles/nature08500 https://www.nature.com/articles/nature08500 : > Using muon spin rotation as a suitable local probe, we apply the method to a real material, the ‘spin ice’ Dy2Ti2O7 (refs 5–8). Our experimental measurements prove that magnetic charges exist in this material, interact via a Coulomb potential, and have measurable currents. This new paper points out how these monopoles are different, at https://www.nature.com/articles/s41563-023-01737-4 https://www.nature.com/articles/s41563-023-01737-4 > The reported duality between magnetic charges and topological AFM textures sheds light on a new class of materials hosting 2D monopolar physics in contrast with other systems that harbour emergent magnetic monopoles, such as the pyrochlore spin ice. Although intriguing, monopoles in spin ice are intrinsically distinct, as they have an underlying gauge charge, which is topological and quantized. Conversely, the emergent magnetic charges in haematite are 2D, not quantized and are topological in the sense that they dress topological AFM textures underpinning them.
- karlkatzke 3y agoMagnets. How do they work?!
- washadjeffmad 3y agoFrom Protector, by Larry Niven. Published by Del Rey in 1973 "Nick Sohl was coming home. ...He had gone mining in Saturn's rings, with a singleship around him and a shovel in his hand (for the magnets used to pull monopoles from asteroidal iron did look remarkably like shovels)... A century ago monopoles had been mere theory and conflicting theory at that. Magnetic theory said that a north magnetic pole could not exist apart from a south magnetic pole, and vice-versa. Quantum theory implied that they might exist independently. The first permanent settlements had been blooming among the biggest Belt asteroids when an exploring team found monopoles scattered through the nickel-iron core of an asteroid. Today they were not theory, but a thriving Belt industry. A magnetic field generated by monopoles acts in an inverse linear relationship rather than an inverse-square. In practical terms, a monopole-based motor or instrument will reach much further. Monopoles were valuable where weight was a factor, and in the Belt weight was always a factor. But monopole mining was still a one man operation. Nick's luck had been poor. Saturn's rings were not a good region for monopoles anyway; too much ice, too little metal. The electromagnetic field around his cargo box probably held no more than two full shovelfuls of north magnetic pole. Not much of a catch for a couple weeks backbreaking labor... but still worth good money at Ceres."
- sxp 3y agoThe math is slightly incorrect. Magnetic field strength falls of with the cube of distance rather than square. For magnetic (or electric) monopoles, the inverse square law applies.
- lambdasquirrel 3y agoIs there a more technical paper / link? Does the flux still sum to 0 over the whole system and this is a localized phenomenon?
- falcor84 3y agoThis seems to be the relevant paper in Nature Materials: https://www.nature.com/articles/s41563-023-01737-4 https://www.nature.com/articles/s41563-023-01737-4 I couldn't find a mention of the flux, but I suppose it could be covered there and I just missed it.
- GlibMonkeyDeath 3y agoIn the "Emergent Magnetic Charge" section, second paragraph: "Finally, we emphasize that the observation of emergent monopoles is fully consistent with the modelling of AFM topological textures in Fig. 2 and does not violate Maxwell’s equation as they are, in fact, sinks and sources of the H^ field." So this is a collective effect of a bunch of magnetic dipoles, and they go on to describe how div B is indeed zero in the material.
- Racing0461 3y agoThis feels like it shoud be bigger news. What's the catch?
- bmicraft 3y agoThe replication crisis, probably
- marginalia_nu 3y agoMagnetic monopoles aren't entirely new in the realm of quasiparticles. We've known about them for quite some while.
- idlewords 3y agoNot actual monopoles but quasiparticles
- Nthringas 3y agotheir magnetic monopole quasi-exists seems like some sort of virtual or model-like result based on emergen properties
- at_a_remove 3y agoThat's a good instinct to have. The answer is that quasiparticles can cover a multitude of sins. My personal Four Horsemen are: -Quasiparticles: We select some property by drawing a box around a set of adjacent particles and computing over those particles. That property is not represented in a single and unattached member of that box. It isn't the real thing but might approximate some nifty functions you wanted if scaled up and embedded in the right material under the correct circumstances. -"...in a simulation": This means that this is only as good as your programming (and databases and libraries) is, on top of how well that programming relates to the math you think represents the system in question. Not only do you not have the real thing, you have bits representing the answer to your imperfect programming based on what you think the math is (and what math can be ignored) in your model. -Analogue of in another system: See sonic black holes. Parallels are drawn between math in one system and math is an entirely different system. Some expect that new inferences can be drawn from the comparison, but you still don't have the real thing, you have a cardboard box with subdividers and you wonder how that applies to high-rises. -Property exists in n-dimensions: Where N is not our three spatial dimensions. It's not the real thing because we don't have anything with just two spatial dimensions, or an extra spatial dimension, but maybe, just maybe, that can lead to some interesting properties on the edge of the thing, or its face, but probably not in the way you would expect. Listen for their hooves during any breathless science press release about physics, materials science, and so on.
- ITB 3y agosounds like room temp superconductors
- andy99 3y ago"""this is the first time we’ve actually seen a __two-dimensional__ monopole in a naturally occurring magnet ... These monopoles are a collective state of many spins that twirl around a singularity rather than a single fixed particle, so they emerge through many-body interactions. The result is a tiny, localised stable particle with diverging magnetic field coming out of it,""" So do I take it that there is some kind of superposition of spins that locally, possibly just in a 2D cross section, appears to have a magnetic field with non-zero divergence? Is \nabla\cdot\vec{B} actually violated somewhere? The language seems pretty cagey. Incidentally, I belive Dirac posited that they existence of magnetic monopoles would explain the quantization of charge.
- Anon84 3y agoYes, it’s a superposition of spins such that the resulting effect is the non-zero divergence
- andy99 3y agoFrom the other thread where this was discussed: In the "Emergent Magnetic Charge" section, second paragraph: "Finally, we emphasize that the observation of emergent monopoles is fully consistent with the modelling of AFM topological textures in Fig. 2 and does not violate Maxwell’s equation as they are, in fact, sinks and sources of the H^ field." So this is a collective effect of a bunch of magnetic dipoles, and they go on to describe how div B is indeed zero in the material. https://news.ycombinator.com/item?id=38549099 https://news.ycombinator.com/item?id=38549099 So this is not a Maxwell's Equations violation or anything, it's just some 'trick' to make a field that somehow locally looks divergent.
- kuchenbecker 3y ago(not a physicist) Dirac proposed a sufficiently long and narrow solenoid would behave as if each end was a magnetic monopole. If the math says it works, then it should be possible in nature. Please correct my understanding if you know better and I'm wrong.
- Anon84 3y agoOk… this still needs to be duplicated, but if it is confirmed it is somewhat of a big deal. They’re not “real” monopoles, in the sense of individual particles that generate a divergent field but rather a quasi-particle (the collective behavior of many individual atoms producing this overall effect). In the worlds of the authors: “These monopoles are a collective state of many spins that twirl around a singularity rather than a single fixed particle, so they emerge through many-body interactions. The result is a tiny, localised stable particle with diverging magnetic field coming out of it,” said co-first author Dr Hariom Jani, from the University of Oxford. That being said, the applications are still pretty exciting and this is something that many people wouldn’t have tought possible at all.
- Loughla 3y agoSo the only context I have for monopoles comes from the Ringworld books and stories (I'm pretty sure that was it). What are the actual uses? I can't get the article to load, if that's in there.
- idlewords 3y ago"In hematite"
- fghorow 3y agoSo, who gets to tell J.C. Maxwell?
- ChrisArchitect 3y ago[dupe] Some more discussion: https://news.ycombinator.com/item?id=38548002 https://news.ycombinator.com/item?id=38548002
- 1letterunixname 3y agoProbably could use qualification in the title because it's clickbait as it stands.
- dataflow 3y agoSomething like this happened back in 2014: https://www.nature.com/articles/nature12954 https://www.nature.com/articles/nature12954
- MostlyStable 3y agoA lot of people are making a point of the "quasi-particle vs particle" distinction. Other than an actual monopole particle being a never-before observed thing, would there be any actual difference in the use and application of a monopole particle vs a monopole quasi-particle? In other words, should we expect that this discovery (and the apparently previously discovered monopole quasiparticles) have the exact same use and application as a hypothetical normal particle monopole?
- thatguysaguy 3y agoWell, my understanding is that some theories of physics predict the existence of monopoles, and some say they can't exist. Finding a real monopole would have an impact on our understanding of physical reality, whereas this is more like an incredibly impressive engineering achievement right? (I could be misunderstanding what the researchers have done)
- clankyclanker 3y agoYeah, it seems like it doesn’t break theory, but it’s a potentially useful product instead, and folks are disappointed.
- nabla9 3y agoThey are very different. These are just emergent magnetic charge distributions in certain materials. Real north and south particles would be like magnetic ions. Really weird batteries and magnetic circuits would become possible.
- NotYourLawyer 3y agoClickbait. Real monopoles would be an enormous deal. This is… moderately interesting.
- acmegeek 3y agoIs this basically a naturally occurring Halbach Array? https://en.wikipedia.org/wiki/Halbach_array https://en.wikipedia.org/wiki/Halbach_array
- jacquesm 3y agoHalbach arrays are non-symmetric but have both poles in equal strength, just not on opposing sides of the array.
- nabla9 3y agoThese are quasi-particles -- emergent collective behavior of a group of particles. Discovering true magnetic monopoly would be biggest discovery in physics since ____. Gauss's law of magnetism violated. This was not it.
- tbrownaw 3y agoIt is not possible for a group of particles to have a divergent field when none of the individual particles have a divergent field. This is not less interesting because it's "just a quasi-particle". This is 2d surface behavior of a solid material. The magnetic fields on the 2d surface act as if there are mobile particles with magnetic charge moving around on the surface.
- nabla9 3y agoThis is far less interesting for two reasons: 1. No new particles for starters. 2. This is not first time magnetic monopoly quasiparticles have been discovered in materials. Mangetic monopoles have been discovered in materials in the past https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.103.030401 https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.10..., https://www.nature.com/articles/news.2009.881 https://www.nature.com/articles/news.2009.881
- andyferris 3y agoIf true, I assume there is a quantum of magnetic... "charge"? E.g. something like h_bar*e? (Sorry, I could go away and figure out the correct units here, but I haven't bothered...)
- deleted 3y ago[deleted]
- elashri 3y agoI did my M.SC in one of the High energy physics experiments looking for "natural" magnetic monopole but now moved for supersymmetry then flavor physics. The title is basically clickbait and personally it triggers a collective truma of hundreds who worked on that during the last 7 decades. Well we might actually have discovered a magnetic monopole in the 80s on the famous valentine's day experiment/incident. [1] As many people here mentioned, these are not the groundbreaking and fundamental particles that we call magnetic monopole that was predicted by Dirac or GUT monopole (predicted by many grand unification theories). This manifestation of spin effects is consistent with the unsymmetric Maxwell's equations we have and wouldn't prompt a modification like if we discovered the "fundamental" magnetic monopole. Well thanks to inflation, we probably never going to be able to see it even it exists. [2] Probably titles like these are part of the reason why HEP physicists have their own APS conference (april) and don't participate in the more generic march conference /S. [1]https://www.nature.com/articles/429010a https://www.nature.com/articles/429010a [2] https://en.m.wikipedia.org/wiki/Big_Bang#Magnetic_monopoles https://en.m.wikipedia.org/wiki/Big_Bang#Magnetic_monopoles
- kmeisthax 3y agoReminds me of how you occasionally get a "GRAD STUDENTS BREAK SPEED OF LIGHT" article and it turns out they just shined a laser on the moon and turned it really fast or something.
- MengerSponge 3y agoBecause it's possible to make things (like a laser spot or a shadow) move faster than the speed of light. It's moving information faster than the speed of light that's tricky.
- superjan 3y agoIs there consensus how actual magnetic monopoles relate to the particles in the Standard Model?
- elashri 3y ago
- gd1 3y ago[dead]
- smegsicle 3y agoI maintain nonetheless that yin-yang dualism can be overcome. With sufficient enlightenment we can give substance to any distinction: mind without body, north without south, pleasure without pain. Remember, enlightenment is a function of willpower, not of physical strength.
- eszed 3y ago> they found hidden patterns of magnetic charges within hematite, including monopoles, dipoles and quadrupoles. I appreciate the context on "monopoles" in this thread. Can anyone help me wrap my head around quadrupoles?
- pbmonster 3y agoThe wiki on this topic is not to bad [0]. Essentially, it's a configuration of 2 south poles and 2 north poles. It's pretty important if you're doing quantitative magnetism. Many magnetic configurations don't generate a pure dipole-like field, but also need higher order contributions - like quadrupole and octopole moment - if you want to model/calculate the field. Quadrupoles also have useful technical properties, you can use one to re-focus the beam in a particle accelerator, for example. In a sense, they act like magnetic lenses. [0] https://en.wikipedia.org/wiki/Quadrupole https://en.wikipedia.org/wiki/Quadrupole
- eszed 3y agoThanks. I looked at that, but I don't have the maths background to follow the real explanation. I get the four bar magnets or four coils stuck together, as an example of the charge state, but that looks simplified to the point that it's maybe not real. I think I'm trying to bridge a gap in my understanding between "this is a convenient way to refer to a complex interaction between multiple magnetic fields", and "this is a object (constructed? naturally occurring?) that I can hold in my hand". Or, maybe that's not even a reasonable mental model / distinction - magnetics be freaky.
- ycui1986 3y agoIn a different perspective, the magnetic field itself is a result of special relativity. The magnetic field is an alternative way to explain electromagnetism without citing special relativity. (Or to say, electrostatic field and special relativity are sufficient to explain everything in electromagnetism, the existence of magnetic field is unnecessary.) If the existence of magnetic field is unnecessary, there is no reason to even search for a magnetic monopole.
- marshray 3y agoDoes this imply the existence of field lines which are not loops? (in 3-D)
- swayvil 3y agoCreate a sphere out of bar magnets. The interior hollow. The shell comprised of bar magnets with all the PLUS pointed inward and the MINUS pointed outward. That would be like a MINUS MONOPOLE. Yes no maybe?