Physicists Discover Never-Before Seen Particle Sitting On a Tabletop (livescience.com) 55
Researchers have discovered a new particle that is a magnetic relative of the Higgs boson. Whereas the discovery of the Higgs boson required the tremendous particle-accelerating power of the Large Hadron Collider (LHC), this never-before-seen particle -- dubbed the axial Higgs boson -- was found using an experiment that would fit on a small kitchen countertop. Live Science reports: As well as being a first in its own right, this magnetic cousin of the Higgs boson -- the particle responsible for granting other particles their mass -- could be a candidate for dark matter, which accounts for 85%t of the total mass of the universe but only reveals itself through gravity. The axial Higgs boson differs from the Higgs boson, which was first detected by the ATLAS and CMS detectors at the LHC a decade ago in 2012, because it has a magnetic moment, a magnetic strength or orientation that creates a magnetic field. As such, it requires a more complex theory to describe it than its non-magnetic mass-granting cousin. [...]
"When my student showed me the data I thought she must be wrong," Kenneth Burch, a professor of physics at Boston College and lead researcher of the team that made the discovery, told Live Science. "It's not every day you find a new particle sitting on your tabletop." [...] "We found the axial Higgs boson using a tabletop optics experiment which sits on a table measuring about 1 x 1 meters by focusing on a material with a unique combination of properties," Burch continued. "Specifically we used rare-earth Tritelluride (RTe3) [a quantum material with a highly 2D crystal structure]. The electrons in RTe3 self-organize into a wave where the density of the charge is periodically enhanced or reduced." The size of these charge density waves, which emerge above room temperature, can be modulated over time, producing the axial Higgs mode.
In the new study, the team created the axial Higgs mode by sending laser light of one color into the RTe3 crystal. The light scattered and changed to a color of lower frequency in a process known as Raman scattering, and the energy lost during the color change created the axial Higgs mode. The team then rotated the crystal and found that the axial Higgs mode also controls the angular momentum of the electrons, or the rate at which they move in a circle, in the material meaning this mode must also be magnetic. "Originally we were simply investigating the light scattering properties of this material. When carefully examining the symmetry of the response -- how it differed as we rotated the sample -- we discovered anomalous changes that were the initial hints of something new," Burch explained. "As such, it is the first such magnetic Higgs to be discovered and indicates the collective behavior of the electrons in RTe3 is unlike any state previously seen in nature." The report notes that this is also the first time scientists have observed a state with multiple broken symmetries.
"Symmetry breaking occurs when a symmetric system that appears the same in all directions becomes asymmetric," reports Live Science. "Oregon University suggests thinking of this as being like a spinning coin that has two possible states. The coin eventually falls onto its head or tail face thus releasing energy and becoming asymmetrical."
The findings have been published in the journal Nature.
"When my student showed me the data I thought she must be wrong," Kenneth Burch, a professor of physics at Boston College and lead researcher of the team that made the discovery, told Live Science. "It's not every day you find a new particle sitting on your tabletop." [...] "We found the axial Higgs boson using a tabletop optics experiment which sits on a table measuring about 1 x 1 meters by focusing on a material with a unique combination of properties," Burch continued. "Specifically we used rare-earth Tritelluride (RTe3) [a quantum material with a highly 2D crystal structure]. The electrons in RTe3 self-organize into a wave where the density of the charge is periodically enhanced or reduced." The size of these charge density waves, which emerge above room temperature, can be modulated over time, producing the axial Higgs mode.
In the new study, the team created the axial Higgs mode by sending laser light of one color into the RTe3 crystal. The light scattered and changed to a color of lower frequency in a process known as Raman scattering, and the energy lost during the color change created the axial Higgs mode. The team then rotated the crystal and found that the axial Higgs mode also controls the angular momentum of the electrons, or the rate at which they move in a circle, in the material meaning this mode must also be magnetic. "Originally we were simply investigating the light scattering properties of this material. When carefully examining the symmetry of the response -- how it differed as we rotated the sample -- we discovered anomalous changes that were the initial hints of something new," Burch explained. "As such, it is the first such magnetic Higgs to be discovered and indicates the collective behavior of the electrons in RTe3 is unlike any state previously seen in nature." The report notes that this is also the first time scientists have observed a state with multiple broken symmetries.
"Symmetry breaking occurs when a symmetric system that appears the same in all directions becomes asymmetric," reports Live Science. "Oregon University suggests thinking of this as being like a spinning coin that has two possible states. The coin eventually falls onto its head or tail face thus releasing energy and becoming asymmetrical."
The findings have been published in the journal Nature.
Ramen scattering on a tabletop (Score:5, Funny)
Been there, I blame the hangover. I didn't detect any new particles though.
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I'm guessing you forgot to shine a laser on it.
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Well... I did.
But don't you worry, a little Lysol and it's taken care of.
Cat physics 101 (Score:5, Funny)
I always suspected my cat could be a good candidate for dark matter: it sits on tabletops, it goes into weird states when I shine a laser at it, and it's, well, black.
However, I have yet to observe a state of my cat with multiple broken symmetries, since it's very hard to carefully rotate the cat without getting a scratch.
Re:Cat physics 101 (Score:4, Funny)
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If the box is too small, the cat can both be in the box and not in the box simultaneously.
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A good old fashioned chainsaw could break the symmetry and discover 2. Ew sub-particles. Or more! Use a meat grinder! You might discover that each particle consists of a whole universe of sub-particles.
Think of me when you get Nobel Prize money.
Suspicion this isn't a real "particle" - preprint (Score:5, Informative)
So I wonder if we still have any people able to properly explain this stuff here on Slashdot? The odd particle physicist used to drop by.
That sounds more like a Higgs boson in a strange state, which would be a very neat thing to be able to show at low energy no matter what.
There seems to be a preprint of the full article available [researchgate.net] for anyone who can fully understand it. It includes things like how they grew the crystals to do the experiments.
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Re:Suspicion this isn't a real "particle" - prepri (Score:5, Informative)
The math that describes particles can also be used to describe various quasiparticles [wikipedia.org] that arise in materials. For instance, one can rigorously define a "phonon" as a particle that carries vibrational energy in a solid material (the phonon is essentially a localized packet of atoms vibrating), or an "exciton" as an electronic excited state (an electron and the corresponding positively charged "hole" it leaves behind), or a "plasmon" as wave of electron excitations at the surface of a metal. All of these are interesting concepts, and defining them as particles is extremely useful. But they are not fundamental particles. They are collective excitations of known entities (electrons, atoms, etc.).
One can thus establish a mapping between the math of fundamental particle physics (the standard model), and the math/behavior in various electronic systems (like superconductors or other "strongly correlated electron" systems). This is useful because in principle if you prove something in one instance, then there is a good chance the analogous thing is true in the other system. So discoveries can go both ways.
The problem is with media reports that do not make these distinctions clear. What the current researchers did was identify an "axial Higgs mode" in a "charge density wave [wikipedia.org]" (CDW) system. They basically discovered a particular kind of excitation of the electron configurations in that material. Very cool stuff. But to then make the leap and pretend that this means they've discovered a new fundamental particle is just bad reporting.
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In fairness to the media, the maths doesn't really distinguish either.
They are all excitations of a field.
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Not a Real Particle, Badly Written Paper (Score:5, Interesting)
They have not observed any fundamental particle but the collective behaviour of a system that possibly mimics the behaviour of a purely hypothetical fundamental particle. However, what they observe is a vector particle i.e. one with angular momentum whereas the Higgs has zero angular momentum.
To get around this they argue that certain, highly speculative theories, have the Higgs as a composite particle not as a fundamental scalar and what they are detecting is something that mimics a state that exists in these theories. Worse, they claim these theories are needed to explain Dark Matter which is utter nonsense - they are, at best, a possible explanation of Dark Matter but are in no way required to explain Dark Matter since there are many other candidate theories e.g. SUSY which fix the hierarchy problem differently.
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This is similar to other discoveries of convenient laboratory physical systems that have the mathematical properties of other physical systems - like the recent "black hole" plasma experiment which models behavior of a black hole event horizon.
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I can not blame Nature here
I can. The abstract itself says: "However, explanations of anomalies (for example, dark matter) rely on further symmetry breaking, calling for an undiscovered axial Higgs mode". This is at best misleading and, strictly as written, not true. Dark Matter does not call for an undiscovered axial Higgs mode since there are plenty of other explanations some of which actually rely on adding new symmetries rather than breaking the ones we have.
The problem is that this is a condensed matter paper written by a co
OK, but what is it? (Score:1, Troll)
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The problem with your reasoning is that your "they" is composed of multiple different groups of people. The reporters are not the scientists. (And they aren't very good reporters, either.)
This isn't a new particle. This is a new organization of a group of particles. As for what it could be useful for, who knows? There's no way to answer that at this time. Usually the answer is "wait a century or two and we'll find out", but occasionally something useful pops up within a decade. Lasers were predicted
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"This isn't a new particle. This is a new organization of a group of particles." I'm not a physicist, so I don't know whether what you say is true--although I have no reason to doubt you--but let me ask a question: What does it mean for something to be a particle? At one point, atoms seemed to be particles, until they were shown to be composed of protons and electrons (and later, neutrons)--i.e., groups of particles. Then protons and neutrons were thought to be particles, until they were shown to be comp
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Completely misleading summary (Score:5, Interesting)
This is a MODEL SYSTEM for a (yet?) undiscovered particle, not its real detection. There are many model systems for hypothetical particles which were never found in nature. Interesting, but far from revolutionary.
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Well, no, not according to earlier posters.
According to them, this is one system that behaves like a different system, which means they can examine the other system at far lower energies.
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Weeell... not precisely. It's one system that can be described by (parts of) the same model that used to describe "the standard model", so the same names tend to get used. But you can't really say that the physics described by "the standard model" will have the same features (It might, but don't count on it.) just because the model system does.
That said, standard physics does include lots of fleeting particles, and we probably don't know the whole zoo. Many are only transitional forms of things that ca
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A cake is real, despite being made of ingredients, so yeah, it's ok to regard systems as real, so that doesn't bother me either. (I'd consider emergent phenomena as also real, but in a different way. "Real" is a complex concept, if you'll pardon the pun.)
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I believe you are saying the same thing as the person you are replying to , just with different words.
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That's a a bit too strong. This is a system that is in some ways analogous to another system. That *might* mean that some other properties it has are also shared by the other system, but it might not.
A waterfall (or flushing your toilet) is in some ways a useful model of a black hole. In most other ways it's not.
Really bad science communication (Score:5, Informative)
As someone with a background in condensed matter physics, this is a case of just awful science communication. What the researches have done is extremely cool (assuming their results hold up to scrutiny), but it does not change our understanding of particle physics.
To make a very long story not quite as long: describing condensed matter systems using just electrons and atomic nuclei is very complicated, because they consist of a huge amount of electrons (there are nearly always a lot more electrons in a small sample than there are sand grains on earth) that all interact with each other. So instead of attempting to throw a computer at simulating this (which even if it were possible would really tell us nothing fundamental about the system, it would just replicate what we see in nature), physicists instead try to write down an effective theory that describes the behavior of the system at "low energies". For example, as long as the electrons in a regular metal don't have enough energy to get completely separated from the metal, you can very often describe the metal using Landau quasi-particles, which are an effective description of the system where the particles in the theory mostly behave like electrons, but they have an effective mass that is due to the band structure arising from the interaction of the electrons with the metallic lattice and also each other. And those theories have been quite successful in making predictions about various materials, for example their specific resistance. Landau quasi-particles are on the simpler end of effective theories that describe the behavior of particles in matter, and there are far more complicated ones. For example, in classical superconductors (such as mercury) you can use the BCS theory to describe them, and there you have so-called Cooper pairs as the effective particles that the theory uses to describe the material.
What the researches have done here is found a new effective quasi-particle in the condensed matter system they were studying that in the end emerges from the interactions of the electrons and nuclei of that sample. But what they didn't find is another particle that can later be considered part of the standard model in particle physics.
Don't get me wrong: this is still extremely cool, and the emergent systems of condensed matter physics are a hugely underappreciated field of study in the public, even though there are tons of phenomena you can find that are quite incredible, especially considering that in the end it's "just" electrons and nuclei underneath all of them. If someone's interested in more there's a famous journal paper from P. W. Anderson called "More is different", originally published in Science quite a while back that provides a good starting point for this.
And I also have to say that even the current standard model of particle physics deals with effective low-energy theories: the photon as we know it is actually an effective particle that arises after the Higgs mechanism that breaks the electroweak symmetry -- in the more fundamental theory you have diferent Bosons that are then mixed to result in both the Photon and the Z0 Boson from the weak nuclear interaction [wikipedia.org].
Furthermore it's not clear whether the current particles in the standard models are not "just" effective particles of a "low energy" limit of a far more fundamental theory that describes our universe. They may be, or they may not be, we just don't know yet. (And maybe we'll never know.)
But this nuance about how the current understanding of particle physics is also working with effective theories to at least some degree doesn't change the fact that the comparisons in the article are only accurate if you already have an understanding of the underlying fields of physics.
In the end I think that the way this result has been communicated does the topic a huge disservice: on the one hand it will likely confuse the public because they will have a specific understanding of "par
Re:Really bad science communication (Score:5, Informative)
What the researches have done is extremely cool (assuming their results hold up to scrutiny), but it does not change our understanding of particle physics.
To make a very long story not quite as long: [...]
What I get from your write-up is that a bunch of phycisists went around theo^Whypothesising with fake "quasi" particles to simplify their calculations and you're telling me they found interesting stuff in their simplified calculations.
I take a bit of issue with the characterization here, especially the word "fake", because if you look at physics in general, it's not easy to define a particle in a way that's both useful to describe the world and also follow the intuition that most people have when it comes to particles.
For example, is a proton a particle? We know it's not fundamental, because we know it's made up of 3 quarks that are held together with gluons. But it's not just these particles simply put together, because 90% of the mass of a proton comes from the energy that holds the quarks together, and only 10% is the actual mass of the quarks. (Don't quote me on the precise percentages, this is from rough memory.) And in the context of anything outside of nuclear processes, I think it's sensible to say that a proton is a particle, even though it's not fundamental.
And the introduction of these abstractions in physics is not just to "simplify calculations", but to actually learn something. For example, let's say you could completely simulate the behavior of a material by adding all the quarks and electrons of that material into a computer and let it simulate what happens - and that computer could 100% arrive at the correct conclusion. Even then you'd have learned nothing about the material itself, because you'd just have made an experiment inside of a computer instead of in the real world. (To give an extreme example: let's say you could simulate a bacterial colony through this method - you wouldn't learn anything about genetics or evolution in this manner.) The abstractions that modern science uses are there to increase our understanding of what goes on, they are a description of the system in a specific limit that helps us make sense of the world, not mere tools to help us calculate things.
Furthermore, theories of various types of quasi-particles are nothing new, and from what I understand having skimmed the research is that these researches haven't come up with the basic idea of that specific type of quasi-particle, they've rather done an experiment that demonstrates that such a quasi-particle is a good description for how the system behaves in that experiment. So in that sense the researches have provided evidence for a previously made hypothesis that such types of quasi-particles could exist in condensed matter systems. (And if you want to dispute the word "exist" here: everything that we use the word "exist" for in day to day usage is actually an abstraction, so I think "exists" does apply here perfectly well.)
Landau quasi-particles are on the simpler end of effective theories that describe the behavior of particles in matter, and there are far more complicated ones. For example, in classical superconductors (such as mercury) you can use the BCS theory to describe them, and there you have so-called Cooper pairs as the effective particles that the theory uses to describe the material.
Nitpick: Your example actually isn't an example: It doesn't illustrate to me that "BCS theory" or "Cooper pairs" are far more complicated than "Landau quasi-particles". It just says so. Useful if I want pointers, not so useful if I want an example.
Well, I'm not sure this will be easier to understand than my previous explanation that went over your head, but if I wanted to attempt to boil down BCS theory to its very basics:
While electrons in general repulse each other (because they have the same electric charge), in specific materials, at low eno
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+5 Insightful
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I take a bit of issue with the characterization here, especially the word "fake", because if you look at physics in general, it's not easy to define a particle in a way that's both useful to describe the world and also follow the intuition that most people have when it comes to particles.
Okay, so the hyperbole points us to another problem in explaining the whole mess. Which is a bit of a neglected part of science and a general failure of science reporting.
My rough understanding is that it's convention, but if you can make up new ones out of thin air just to... make calculations fit and improve your understanding, well, maybe that "convention" part needs better explanation to keep it understandable to the interested layman.
Like (a less cynical version of) me, with a background in highscho
Re:Really bad science communication (Score:5, Informative)
Like (a less cynical version of) me, with a background in highschool physics 30 years ago and having read _a brief history of time_ maybe 20 years ago.
As an aside: I don't think "A brief history of time" (or any popular science book by Hawking) is a good book by any standard. Hawking was an extremely brilliant man, but communicating clearly was not one of his strong suits in my opinion. Even with my background I don't grasp most of what he's trying to say in his popular science books.
The abstractions that modern science uses are there to increase our understanding of what goes on, they are a description of the system in a specific limit that helps us make sense of the world, not mere tools to help us calculate things.
Okay, but you'd have to explain that is what you're doing. And probably also how you know you're not making up things from whole cloth and thus are creating a fantasy world where your math is especially elegant, but that has lost connection to the real world. (*cough* q.v. "modern" economics *cough*)
I'm not going to touch that economics comment with a ten foot pole because it's not my field of expertise. But in physics everything boils down to experimental confirmation: you can write down any theory you fancy, but in the end the experiment decides whether a theory is applicable or not. (Which is why quite a few people argue that string theory belongs in math and not in physics for now, for example.)
That said: I believe you should maybe look at the way physics works differently. Take Newton's theory of gravity, for example. We've had a much more accurate theory of gravity for over 100 years (Einstein's GR paper is from 1915), but I don't think it's useful to say that Newton was wrong. While there are some areas where the effects of Einstein's better theory become relevant, in many cases engineers and physicists still use Newton's theory of gravity for calculations because it's still applicable to a high degree of precision.
Even if we find a much more accurate description of condensed matter systems tomorrow that doesn't rely on quasi-particles -- that doesn't mean that a quasi-particle description isn't correct, it just means it's an incomplete way of viewing the world.
Furthermore, theories of various types of quasi-particles are nothing new, and from what I understand having skimmed the research is that these researches haven't come up with the basic idea of that specific type of quasi-particle, they've rather done an experiment that demonstrates that such a quasi-particle is a good description for how the system behaves in that experiment. So in that sense the researches have provided evidence for a previously made hypothesis that such types of quasi-particles could exist in condensed matter systems. (And if you want to dispute the word "exist" here: everything that we use the word "exist" for in day to day usage is actually an abstraction, so I think "exists" does apply here perfectly well.)
So they tried to show, and possibly succeeded showing, that the world they made up out of quasi-particles isn't fantasy la-la land but still has bearing on reality. That's useful to know. Might well be the take-away needed for the headline.
Well, quasi-particles are nothing new, the general concept has been established in condense matter physics for over 60 years, and they are an accepted way of describing condensed matter systems for decades. (They don't describe all condensed matter systems, in some systems a quasi-particle description does not make sense. There, other effective low energy theories exist.) What the authors of this paper did was show that a specific type of quasi-particle that was never seen before has now been experimentally observed.
Well, I'm not sure this will be easier to understand than my previous explanation that went over your head, but
Slashdot, take note! (Score:1)
"News for Nerds. Stuff that Matters"
Now, I think the leading candidate is:
"Really bad science communication"
I hope that Hemos and CmdrTaco are spinning in their graves. It is amazing how much Slashdot has deteriorated over the last decade or so. But it's not choosing the buck the trend! Viva Slashdot!
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the comparisons in the article are only accurate if you already have an understanding of the underlying fields of physics.
They are also only accurate if the higgs is a composite particle which is very far from certain and even arguably likely wrong.
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The paper's abstract sets realistic expectations, but the popularized description seems extravagant. The abstract says: "Thus, we provide a means for measuring quantum properties of collective modes without resorting to extreme experimental conditions."
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Thank you, indeed the headline was quite "unusual" as discovering a new particle would be a big thing - there are very few candidates for new particles considering existing theories and anything outside would mean "new" physics, and for sure tabletop/kitchen device is very unlikely to make it happen.
Out of a quasi particle to simplify calculations (which is an achievement worthy celebrating in itself) to "new particle discovered on the tabletop" - o the popular journalism, ... well let's just not comment on
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You're already +5, so I can't moderate higher. Thanks very much for the clarification.
As a side note, also thanks for being gentle with the science reporters. The job is not an easy one. I'd make a joke here about English Majors jumping into it when they realize they didn't want to teach High School, but I honestly couldn't do either job so the joke wouldn't work. :)
Probably not a particle that can exist in vacuum (Score:2)
I suspect this is a behavior of propagation in the unusual medium they studied that is in some way an analog of the Higgs boson. That not the same thing as an actual particle that can exist in a vacuum. Just like a phonon which is the description of sound waves as a particle.
And that would make the speculation about it being a dark matter candidate very unlikely.
Have they checked down the pack of the sofa (Score:1)
New particle..? (Score:3)
Worst.. particle.. ever.
Tabletop Experiment Might Show New Particle (Score:3)
What's with the titles nowadays....
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Yeah, if they're playing silly semantic games anyway - why not say "discovered on the hood of a car" or "discovered in a bathtub" or "discovered on a twin mattress"?
This is why (Score:2)
you really shouldn't dust that often.
Tritelluride? (Score:2)
Does this mean Mr. Fusion is (Score:1)
...just around the corner?
Just a divine joke (Score:2)
The Allahmighty is making new ones just to mess with us.
...my student showed me the data I thought she ... (Score:1)
"When my student showed me the data I thought she must be wrong," Kenneth Burch
His female student made a groundbreaking physics discovery. Clearly this man is going to win a Nobel Prize. That is, afterall, how it works. Female students make discovery, professor gets Nobel Prize. Congrats.
Love tabletop physics! (Score:1)
Come to think of it, wasn't John Bell's revolutionary entanglement experiment also a tabletop experiment? I think so.
When my student showed me the data I thought she m (Score:1)