[HN Gopher] The existence of a new kind of magnet has been confi...
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The existence of a new kind of magnet has been confirmed
Author : revicon
Score : 303 points
Date : 2024-02-15 16:12 UTC (1 days ago)
(HTM) web link (www.newscientist.com)
(TXT) w3m dump (www.newscientist.com)
| nonrandomstring wrote:
| Whatever happened to "bubble memory"?
|
| [0] https://en.wikipedia.org/wiki/Bubble_memory
| wk_end wrote:
| Your own link tells you! The introduction of
| dramatically faster semiconductor memory chips pushed
| bubble into the slow end of the scale, and equally dramatic
| improvements in hard-drive capacity made it uncompetitive
| in price terms.[1] Bubble memory was used for some time
| in the 1970s and 1980s in applications where its non-moving
| nature was desirable for maintenance or shock-proofing reasons.
| The introduction of flash storage and similar
| technologies rendered even this niche uncompetitive, and
| bubble disappeared entirely by the late 1980s.
| masspro wrote:
| There was a Konami arcade cabinet that (tried to) use bubble
| memory! It was considered a failure. Also from Wikipedia[0]:
|
| > It was considerably more expensive than ROM chip-based
| boards and extremely sensitive to electromagnetic fields that
| could render the game unplayable.
|
| You can find the start-up sequence of these on YouTube. It's
| pretty...idiosyncratic. It took forever because it had to
| physically warm the memory up. Though I guess taking forever
| is irrelevant if you are turning on a machine only once in
| the morning. In fact, the music in the ROM it plays while
| starting up was named "Morning Music".
|
| [0]: https://en.wikipedia.org/wiki/Bubble_System
| nonrandomstring wrote:
| Amazing. I never realised it got to commercial production,
| just that about 1985 it was heralded as the next amazing
| thing - with however many libraries of congress per
| fingernail etc.
| Dylan16807 wrote:
| > with however many libraries of congress per fingernail
| etc.
|
| That's a bold claim!
|
| I found a NASA document from 1976 that expected bubble
| memory to reach about a terabit per _cubic meter_ by the
| year 2000. And then you need over a hundred terabits for
| a library of congress.
| https://core.ac.uk/download/pdf/42884743.pdf
| mewpmewp2 wrote:
| Likely ruined by the reputation of bubble sort.
| m463 wrote:
| went the way of the stringy floppy
| Aardwolf wrote:
| Also, MRAM, PRAM and FeRAM
| the8472 wrote:
| MRAM is available as a niche product, it just hasn't achieved
| the promise of being cheap and dense as dram, fast as sram,
| nonvolatile and higher write endurance than flash at the same
| time. It ticks maybe two or three of those boxes, which is
| still something.
| pugworthy wrote:
| Magnets - We thought we knew how they worked.
| adamhartenz wrote:
| Anyone who claims they know how magnets work, are a liar
| archgoon wrote:
| Strong words. Why do you believe no one knows how magnets
| work? What would be a satisfactory answer?
| blix wrote:
| I believe GP is a riff on the common joke among physicists:
| "Anyone who claims to understand quantum mechanics is
| either lying or crazy."
|
| To be more specific in the case of magenetism, you can say
| that, for example, ferromagnetism arises from the alignment
| of magnetic moments into cohesive domains, where the
| individual magenetic moments arise on the atomic level from
| unpaired electrons in the d or f orbitals.
|
| But if you poke at that (incomplete) answer a little bit,
| things start to get complicated. How exactly do magnetic
| domains align? What if there's a disruption in crystal
| structure? Are there other sources of magnetic moments?
| Where does the magnetic moment on an elementary particle
| come from? The answers to these questions get pretty
| complicated and questions like these motivate a lot of
| active scientific research.
| fsckboy wrote:
| we don't know why or how there is electric charge (and
| their related fields), we just know that there is electric
| charge; it's one of the properties of the universe; same
| with gravity. We have uncovered mathematical laws of charge
| and and their relationship (via div, grad, curl and all
| that) to magnetic fields, but we don't know how or why,
| just what is.
|
| My source is Feynman.
| wolverine876 wrote:
| Feynman was awhile ago.
|
| But which Fenyman?
| nyrikki wrote:
| "A map is not the territory it represents, but, if
| correct, it has a similar structure to the territory,
| which accounts for its usefulness." -- Alfred Korzybski,
| Science and Sanity
|
| You are confusing conceptual models of reality with
| reality itself.
|
| The Scientific Method is used to construct an accurate,
| reliable, self-consistent, non-arbitrary representation
| of the world, which are models.
|
| QED is one of the most stringently tested theories in
| physics. But it is a model and will never be proven as
| 'True', we just get more confident in he model after it
| passes test after test, after test, after test.
|
| But it is still just the map and not the territory
| itself.
|
| Feynman knew this well:
|
| https://www.youtube.com/watch?v=EYPapE-3FRw
| javajosh wrote:
| I think you misunderstand the sentiment. You can know how
| they work; you cannot know why they work.
| krapp wrote:
| For a better tomorrow?
| malodyets wrote:
| Physics answers what and how. Why is for philosophers and
| theologians.
| mocha_nate wrote:
| The why is not required. It works whether we want it to or
| not.
| dylan604 wrote:
| Magnets are part of the Elves technology. That's why there's
| a magnetic North Pole. So, we do know how they work...magic
| of Christmas
| bandyaboot wrote:
| It's why magnets only work for people who truly believe.
| 1letterunixname wrote:
| Yes, and electricity uses magic smoke technology.
| :magic smoke: n. A substance trapped
| inside IC packages that enables them to function
| (also called blue smoke; this is similar to the archaic
| phlogiston hypothesis about combustion). Its
| existence is demonstrated by what happens when
| a chip burns up -- the magic smoke gets let out, so it
| doesn't work any more. See {smoke test}, {let the smoke
| out}. Usenetter Jay Maynard tells the
| following story: "Once, while hacking on a
| dedicated Z80 system, I was testing code by blowing EPROMs
| and plugging them in the system, then seeing
| what happened. One time, I plugged one in
| backwards. I only discovered that after I realized
| that Intel didn't put power-on lights under the quartz
| windows on the tops of their EPROMs -- the die
| was glowing white-hot. Amazingly, the EPROM
| worked fine after I erased it, filled it full of zeros,
| then erased it again. For all I know, it's
| still in service. Of course, this is because
| the magic smoke didn't get let out." Compare the
| original phrasing of {Murphy's Law}. curl
| -fsSL https://jargon-file.org/archive/jargon-4.4.7.dos.txt
| | LC_ALL=C sed -n '/^:magic smoke/, /^:/{/^:mail
| storm/d;p;}'
| chasil wrote:
| James Clerk Maxwell is a liar?
|
| Are you telling me that this is not true?
|
| [?] * B = 0
|
| EDIT: See? Right there on the tin.
|
| https://en.m.wikipedia.org/wiki/Maxwell's_equations
|
| EDIT2: The meaning of this statement is that the sum of
| magnetic lines of force entering a frame is equal to those
| exiting; there are no magnetic monopoles.
| bobsmooth wrote:
| Why tho?
| chasil wrote:
| There are four fundamental forces that are observed: the
| strong nuclear force, the weak nuclear force, the
| electromagnetic force, and the gravitational force.
|
| Why these forces exist, we cannot know.
|
| How these forces act is a question of physics and
| mathematics.
|
| https://en.m.wikipedia.org/wiki/Fundamental_interaction
| postalrat wrote:
| Physics and math are things people invented to build
| models of what we see. They don't govern reality.
| chasil wrote:
| If you like electricity, and everything that it does for
| you, then you must understand that it is absolutely
| described by Maxwell's laws.
|
| No exceptions.
| chasil wrote:
| I have upvoted you, and I don't think that you should be
| punished for what you have said.
|
| There are ways that it is wrong, and ways that it is right.
|
| ...if you had said "why?" and not "how?" then you would be
| absolutely right.
| yakshaving_jgt wrote:
| Somebody get ICP on the phone this instant.
| whyenot wrote:
| What is ICP?
| interbased wrote:
| Insane Clown Posse. The source of the "magnets, how do they
| work" meme since it's a lyric from their song.
| TehCorwiz wrote:
| Insane Clown Posse. They have a song called Miracles https:
| //en.wikipedia.org/wiki/Miracles_(Insane_Clown_Posse_s...
| which has the line: "Fucking magnets, how do they work?"
| which became a meme for a while.
| user_7832 wrote:
| I highly recommend watching its video if anyone hasn't.
| It's got a nice groove, the lyrics are actually quite
| appreciative of nature... but the magnet line is a real
| weird inclusion.
|
| Link - https://www.youtube.com/watch?v=_-agl0pOQfs
| japhyr wrote:
| I was a high school science teacher when that song was
| popular. That was a fun time!
| 1letterunixname wrote:
| Older school hiphop gritty downshift order when The
| Beastie Boys or Biggie just won't work:
|
| 1. Dr. Octagon (Kool Keith)
|
| 2. Insane Clown Posse
|
| 3. Bubb Rubb (also memetic) https://youtu.be/DYRDuOCKr2A
| a_gnostic wrote:
| Inductively Coupled Plasma A method to energize samples for
| photometric analysis.
| tabtab wrote:
| The Orange Man was right!
| dylan604 wrote:
| Yes, I thought it was the Covid vaccine that made people
| magnetic
| jfengel wrote:
| We do. This is just a different way to build one. It's a
| configuration of atoms that we didn't realize could be made
| stable, and their atom-level magnets line up in a novel way. We
| understand atomic magnetism pretty well.
| altruios wrote:
| article limit paywall: any workaround?
| davideg wrote:
| https://archive.is/m1qfh
| gary_0 wrote:
| This works for me:
| https://web.archive.org/web/20240215162623/https://www.newsc...
| TaylorAlexander wrote:
| Here's a nice non-paywalled article on this:
|
| https://phys.org/news/2024-02-altermagnetism-experimentally....
| Nevermark wrote:
| Spintronics, which these magnets might be useful for, have
| several potential advantages for low power, speed and quantum
| coherence for quantum computing.
|
| So a very nice discovery. Love how we keep finding strange new
| useful modes of matter at "the bottom".
|
| Computing substrates are far from reaching any kind of final form
| or limit.
| angiosperm wrote:
| I thought we had long since established that magnetism is
| illusory, an artifact of special relativity.
|
| But it seems like a thin film of this stuff would be a good thing
| to skim an electron beam over, if you wanted some extremely
| short-waved photons.
| pdonis wrote:
| It's not illusory or an "artifact", since you can have
| electromagnetic field configurations that cannot be reduced to
| simple electrostatics (i.e., electric field but zero magnetic
| field) by picking an appropriate frame.
|
| Special relativity helps to explain why, even if you have a
| configuration that _is_ purely electrostatic in one frame, it
| won 't be purely electrostatic in other frames. But that's not
| the same as saying that _all_ electromagnetic field
| configurations are that way. They aren 't.
| AnimalMuppet wrote:
| The magnetic _field_ may be an artifact of special relativity.
| Magnetic _materials_ are not relativistic artifacts.
| chasil wrote:
| The electromagnetic force is one of the four fundamental
| forces.
|
| It cannot be reduced.
|
| https://en.m.wikipedia.org/wiki/Fundamental_interaction
| ithkuil wrote:
| I think GP alluded to
|
| https://en.m.wikipedia.org/wiki/Duality_(electricity_and_mag.
| ..
| lupire wrote:
| Why isn't electricity an illusory artifact of relativistic
| magnetism?
| pdonis wrote:
| The article's title is misleading: they actually mean a new kind
| of _permanent magnet_ (that was theoretically predicted but hadn
| 't been observed until now), _not_ a new kind of _magnetism_ (as
| in, something not predicted or accounted for by our existing
| theory of electromagnetism).
| dang wrote:
| Ok, we've downgraded magnetism to just a magnet in the title
| above. Thanks!
| nhatcher wrote:
| If I am reading correctly it is a new kind of magnetism:
|
| https://en.m.wikipedia.org/wiki/Magnetism#Types
|
| And I am not sure it can be called a magnet. It's definitely
| a new kind of magnetic state
| pdonis wrote:
| _> it is a new kind of magnetism_
|
| It's a new kind of magnetic _medium_ that had not been
| previously observed. It is _not_ something that can 't be
| explained by our existing theory of electromagnetism.
|
| _> I am not sure it can be called a magnet._
|
| It's an object that has magnetic properties. That's a
| magnet. It's a different _kind_ of magnet from those we had
| previously observed.
| lupire wrote:
| Each magnetic medium exhibits its own kind of magnetism.
|
| Sometimes words are slightly ambiguous. This is not a
| hill to die on.
| pdonis wrote:
| _> Each magnetic medium exhibits its own kind of
| magnetism._
|
| I agree that it is sometimes described this way, although
| as one commenter upthread said, such use of language is
| more common when physicists are talking among themselves,
| not when they are talking to the public.
|
| The comments in this discussion indicate that I am by no
| means the only one who was confused by the original
| wording. So I think the change was helpful.
| purpleflame1257 wrote:
| Yeah, for a minute there I thought they had found the monopole
| db48x wrote:
| Monopoles are already accounted for though, because they're
| explicitly ruled out by the character and form of the laws of
| electromagnetism. [?][?]B = 0, or "the divergence of the
| magnetic field is zero".
| eigenket wrote:
| I mean I we found a magnetic monopole then we'd just change
| that one of Maxwell's equations so it looks like the
| corresponding electrical equation Div(E) = r/e. It
| essentially just happens that the thing which correspond to
| r for the B field is 0.
| db48x wrote:
| Except that if the divergence of the magnetic field were
| anything other than zero, the laws as presently written
| wouldn't successfully predict electromagnetic effects.
| Because the laws as currently written _do_ make
| predictions, and exquisitely precise predictions at that,
| the divergence must be zero with no monopoles at all or
| so close to zero that monopoles would be extraordinarily
| weak if they did exist. Their effects would be so slight
| that they would be useless for any practical purpose
| except possibly impressing the Nobel committee.
| eigenket wrote:
| I don't really understand your point here. If we do
| discover magnetic monopoles (which would not necessarily
| be very weak but instead very rare) then we would take
| the equation
|
| Div(B) = 0
|
| And update it to say
|
| Div(B) = sigma
|
| Where sigma is a field describing the monopole density.
| Theres a ready "gap" in Gauss' law for magnetism where
| you can easily stick monopoles. Of course the divergence
| would be zero in the absence of monopoles, just as the
| divergence of the electric field is zero in the absence
| of electric monopoles, but decidedly non-zero when
| there's an electron around.
| shric wrote:
| It looks like this is already a polarizing topic
| data_maan wrote:
| +1 ;)
|
| Not too many got the joke it seems :D
| shric wrote:
| Well I wasn't sure if it would be downvoted due to low
| effort, but it got 17 points, so thanks :p
| rnhmjoj wrote:
| The fact that standard EM theory with zero magnetic
| charge works well only proves that normally there aren't
| lots of magnetic monopoles floating around: they could be
| very short-lived particles or strange phase of the
| matter, but still real and Maxwell's equations don't say
| anything about this.
|
| As far as I know there's no mathematical or physical
| reason to outright forbid magnetic monopoles. On the
| contrary, there is a well-known argument by Dirac that
| says that if they would exist then charge is quantised,
| which we know it is. This is one of the reasons people
| are still looking for magnetic monopoles.
| ryan-duve wrote:
| I think your point is the current Maxwell equations
| explain physics so well that if we change them to
| accommodate magnetic monopoles they would have to be
| worse. If I understand you right, it overlooks that we
| can add terms[0] to Maxwell's equations that don't affect
| predictions in a world free of magnetic monopoles:
|
| [?][?]E = r(electric) / [?]0
|
| [?][?]B = m0 * r(magnetic)
|
| [?]E = -m0 * J(magnetic) - [?]B/[?]t
|
| [?]B = m0 * J(electric) + (m0)([?]0)([?]E/[?]t)
|
| We could switch every physics textbook to using the above
| today, and the only difference would be setting
| r(magnetic) and J(magnetic) to zero when there are no
| monopoles in the problem.
|
| [0] Griffiths Introduction to Electrodynamics 3E, Section
| 7.3.4
| xmcqdpt2 wrote:
| If anything it's frustrating that there aren't monopoles,
| because if there were, we could make the E and B
| equations symmetrical under interchange of the fields. It
| would be a lot prettier, and I think it would be easier
| to teach to undergrads.
| danbruc wrote:
| I mean you could just do that and tell the students that
| the magnetic charge and current densities are always zero
| unless we eventually discover monopoles.
| elashri wrote:
| This is incorrect, you can put non-zero divergence of
| magnetic field and all the equations and predictions
| stays the same. Better it would make Maxwell's equations
| symmetric under exchange of fields and sources. \
|
| > so close to zero that monopoles would be
| extraordinarily weak if they did exist
|
| Why? I can't think of a reason why would this be the
| case? You are not solving Maxwell's equation for the
| universe. You can have divergence of electric field
| closed to zero because you have very low density (the
| field source) in the region you are studying.
| elashri wrote:
| When Maxwell first published his work with the equations,
| it contained non-zero B divergence. We say that density of
| magnetic monopole (which should be there instead of zero)
| is zero because we did not find any monopoles yet (maybe
| ever!). If we discover a monopole, and we remove this zero,
| there will no problems with EM theory, and actually we can
| explain some other things like quantization of electric
| charge (why all charge are integer multiple of electron
| charge).
|
| So no, it was not explicitly ruled out by Maxwell's
| equations. It is not even ruled out because we did not
| explore the full phase space. And it depends on which
| monopole you are talking about (Dirac monopole, GUT
| monopole or EW monopole).
| EvgeniyZh wrote:
| I'd say that, for example, paramagnetism is kind of magnetism,
| not kind of magnet.
| pdonis wrote:
| I agree that one could say that, but it still only makes
| sense in a context where you have an _object_ that has this
| kind of magnetism, i.e., a magnet. And the same is true of
| the "magnetism" whose discovery this article is describing:
| it's a kind of magnetic state of an object.
| planede wrote:
| Paramagnetism/diamagnetism doesn't apply to "magnets",
| which I assume you use to refer to materials that have
| external magnetic field without applying external
| excitation.
| ddingus wrote:
| I was looking for the same and hot the paywall.
| z2h-a6n wrote:
| As a condensed matter physicist (working in the same field but
| not on altermagnetism specifically), I would say this is being
| much more picky about the language than most people in the
| field tend to be. Moreover, I'm not sure you're even right
| about the language.
|
| You are correct that this doesn't involve any changes to our
| understanding of electromagnetism in general; whether or not
| that means that _altermagnetism_ is not a new type of
| _magnetism_ is a matter of semantics. If I read in a paper or
| heard in a seminar that "altermagnetism is a new type of
| magnetism", I would not quibble with the language, though that
| phrase by itsself is almost tautologically pointless.
|
| If you want a more technically meaningful phrase, I would
| propose that altermagnetism is a newly-discoved "magnetically
| ordered phase". Of course that doesn't fit so well in a
| headline.
| pdonis wrote:
| _> I would say this is being much more picky about the
| language than most people in the field tend to be._
|
| Perhaps, but I think that when communicating with the public
| (as opposed to communicating with other physicists), "a new
| kind of magnetism" suggests something that isn't explained by
| our current theories, not just something that our existing
| theories predict but hadn't been observed before.
| sesm wrote:
| > altermagnetism is a newly-discoved "magnetically ordered
| phase"
|
| I would prefer this headline.
| lanza wrote:
| Sounds like shorthand terminology in your subfield is okay
| with the usage of "magnetism." But that's local slang, as a
| (former) high energy theorist I interpret the phrase "a new
| form of magnetism" as a new gauge theory or something equally
| spectacular. So I just rolled my eyes at the headline.
| Suppafly wrote:
| As someone who isn't a physicist, headlines like this make me
| think they discovered magnets that work with some non-ferrous
| material, which would be amazing. But then I was like
| "wouldn't that be crazy" and then came to the comments
| specifically to see what the actual explanation would be.
| _obviously wrote:
| Spintronic effects is how Saturn is a natural, planet-sized
| computer.
| rashkov wrote:
| Go on...
| CarRamrod wrote:
| >OK Saturn, play Thick As A Brick on Earth at 100% volume
| demondemidi wrote:
| Is that from a book? I'd like to read it if so.
| tempodox wrote:
| It's from Jethro Tull.
| demondemidi wrote:
| I know that album inside and out. What is the Saturn
| reference and how does it relate?
| DeathArrow wrote:
| So in the future Arm vs x86 flame wars will be replaced by
| spintronic vs quantum vs carbon vs optical computers flame wars.
| doublerabbit wrote:
| Does this enable hover-boot, hover-tech capabilities yet?
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