10 Subatomic Stories: Understand neutrino oscillations like the pros

[@jomiar309]

You are seriously one of the best science communicators I've ever seen! Your enthusiasm for physics is contagious and palpable!

[@MrGonzonator]

A man walks into the particle store to buy particles to make atoms. He browses, finds what he needs and pays for it. However, when looking on his receipt afterwards, he sees that the clerk forgot to ring up an item. He says "Sir, you forgot the neutrons". The clerk looks up at him and says: "No worries, they're free of charge".

[@esra_erimez]

🤣

[@paulmichaelfreedman8334]

A bit like the scientist who froze himself to absolute zero, but he was 0K

[@MrGonzonator]

@Z3U5 The bartender says, “Go home. We don’t serve faster-than-light-particles here.” A tachyon walks into a bar.

[@MrGonzonator]

@Z3U5 Atom 1: “I think I lost one of my electrons somewhere.” Atom 2: “Are you sure?” Atom 1: ”Yes, I’m positive!”

[@rixtino3216]

Good one

[@guilleteru]

0:33 I love his smile when he talks about these topics which he is so passionate about!

[@TheReaverOfDarkness]

I came to this video with a Dunning-Kruger-like perception of having mostly understood simple neutrinos, and left with my head full of details, loose ends, and a general perception of how lost the experts feel. Well done! Where previously I wanted a video all about neutrinos, I now want a SERIES about neutrinos!

[@militantpacifist4087]

I was going to make a neutrino joke but it’s just going to fly through you.

[@alexv3357]

In one ear, and right out the other

[@clancyjames585]

It was a pretty weak joke anyway

[@freddan6fly]

@@clancyjames585 It was a pretty weak joke because the interaction was weak.

[@rhoddryice5412]

I caught this joke in my pool.

[@TerranIV]

Thanks for the straight talk on neutrino flavor oscillations and masses. Very interesting! Is it correct to say that the fact that neutrinos change flavor indicates they have mass because a massless neutrino would 1) move at light speed and 2) in doing so, not experience time from it's inertial frame, hence 3) it wouldn't have "time" to change flavor or am I incorrect that any light-speed particle (photon, gluon, "graviton," etc.) does not experience time in their inertial frame? I look forward to the next video!

[@simbaonsteroids8836]

When neutrinos oscillate can the mass of the particle change, if so where does the energy for the new mass come from/go?

[@iamcomcy]

Quantum foam?

[@MusicalRaichu]

first question i thought of two. i hope Don answers it in the next video. you hear Don?

[@clancyjames585]

So a neutrino's "mass", when it is created, is a superposition of the three mass states (the diagram of that 3x3 matrix shown was a little simplified, there are non-zero values at all places). So you can think of it have either no defined mass, or a probabalistic mean of the masses (like the average of a dice roll is 3.5). In theory, you could have a situation where a neutrino would be created, but there is not enough energy to create this mass - but this is such little energy there is no known situation where this would occur. We also have no known method of asking a neutrino "what is your mass" (this would be quantum gravity). All we can do is ask "what is your flavour?" at some point after it is created, and potentially get a different answer. But even though the "mean mass" of a tau neutrino will be different to that of an electron neutrino due to different combinations of the mass states, the weak interactions do not depend on this. What they do depend on is the mass of the electron, muon, or tau, which are WAY heavier than a neutrino (by a factor of at least 500,000 for an electron and the heaviest neutrino, maybe a million with the latest limits). This means you can have a neutrino with energy that is low enough that certain interactions where, say, a tau neutrino would otherwise create a tau and prohibited.

[@Mr.Nichan]

I wonder if it could just be changing speed or if there are problems with that. I think the answer to this question is deeply tied to the question of how we know the difference between the masses, since the way we know could have something to do with measuring the results of the transitions. It is very odd that we wouldn't know the sign of the difference (i.e., which is bigger), which definitely limits what ways we could be knowing the difference, though I don't what it limits them to.

[@fabianjanen7099]

Thank you so much for this amazing video series Mr. Lincoln!

[@Familylawgroup]

I want to personally thank you for attempting to simplify physics for fans who lack the education to immerse themselves in the depths of the topics. I only found your channel a few weeks ago and I look forward to new videos.

[@mr51406]

The sheriff of Fermi City posted this sign: Wanted. Schrödinger’s cat. Dead and alive.

[@kdub1242]

Deputy Heisenberg is not certain about that.

[@shahanshahpolonium]

@@kdub1242 the cat is everywhere, since it not anywhere

[@samstark568]

When neutrinos oscillate do they instantly transform from one type of neutrino to another or is it gradually overtime like an electron neutrino gradually becoming more muon neutrino until it's identified as mostly a muon neutrino.

[@Andrew-rl3uo]

Their composition changes gradually in time so the probability of being detected as an electron neutrino (or muon, or tau) will change as well.

[@TerranIV]

If they didn't change instantly then there would be a period of time where they were "not" a neutrino of ANY flavor. It seems like the transition would have to be instantaneous, with some other particle interaction (weak bozon of some kind?) causing the flavor change. Other particle interactions probably wouldn't change the flavor, but would only change the mass. (At least that is what I got from the video.) I would love to see a follow up video on the prevailing theories for the exact mechanism for flavor change!

[@kylebowles9820]

T P +1 for good analogy and a bonus internet for the thought (and reality) of "discrete pants" LOL

[@GrooveQuest]

They should be morphing between states, the oscillation shown in the video is a Sine wave. If the transition was instantaneous, the oscillation would show up as a Square wave.

[@clancyjames585]

Andrew Rreevs is correct. The probability changes gradually. When you make a 'measurement', the change is sudden.

[@BothHands1]

i don't have a question, just wanna let you know i love your personality, your excitement, your smile, and obviously the way you are able to explain difficult topics in a way that i can understand. i think i found your channel from either pbs spacetime or maybe physics girl. whoever it was, i'm glad they led me here :)

[@tangofan4u]

2:03 "If neutrinos can change their identities, it means that neutrinos have mass." In what ways is mass a prerequisite for that?

[@drdca8263]

If they had no rest mass, then they would move at the speed of light, and, I want to say that that would imply that they couldn't change over time, but I don't understand how that squares with like, interference patterns of light and such.

[@jenaf372]

@@SF-tb4kb there is a difference between rest mass and relativistic mass. 'Massless' means 0 rest mass. (Like photons)

[@CdrRogue]

My fuzzy understanding is that it's down to the fact that massless particles don't "experience" time. If something changes en route, it means it experiences moments of time during the journey, which means it has mass.

[@sofiatgarcia3970]

Understand neutrino oscillations like the pros. Right, like this cabinetmaker is going to understand any of this other than on the most basic level. But any understanding I gain is more than I had before and it's thanks to you good doctor.

[@1ofthesonsoflight]

Tell us about “Displacement Vertices “ The long- lived particles that pass completely through the CMS Detectors , the effects they might cause and how they track them down outside of the CERN facility

[@SuperStingray]

How does momentum conservation play into neutrino oscillations? Do neutrinos speed up and slow down as their mass changes or do they have a constant velocity and their momentum as a whole oscillates?

[@petrosian5656]

Is the expectation value of mass different for each flavor of neutrinos? And if so, does the velocity of a neutrino change as it oscillates between different flavors (due to conservation of energy)?

[@ChrisWalshZX]

Wow! So I knew about the principles of Neutrino Oscillation but the whole interchangable mass and relative mass values is new to me. Thanks Don. Excellent delve into some new physicsing! 😁

[@ianluebbers5492]

What happens to the fundemental forces when the temperature approaches absolute zero? Is there evidence of more forces coming into existence?

[@InsouciantSoul]

Awesome. Loving the content lately on your channel! Don't be afraid to do some more long-form videos. I would be more than happy to sit through a few ads if I was watching a 30 minute long, or even up to a one hour long, video discussing and instructing on topics like the one featured in this video. If you think doing some long form videos is feasible, but are still holding off thinking that would just be too long and as a result involve too much video editing in order do ... Well, fear not! I've got your answer: Just make it a podcast! I already subscribed yesterday :)

[@nerd31415926535]

Question: at 1:40 neutrino oscillation is plotted as a function of distance traveled. In who's frame of reference? If I travel alongside a neutrino so that it is not moving relative to my spaceship, will I observe oscillations?

[@jiioannidis7215]

How do we know which type of neutrino our detectors detect? The answer to the missing solar neutrinos mystery was neutrino oscillations, which implies that we were only detecting one neutrino type (would that be u_{e}?). If we are not sure about the masses, how can we tell them apart?

[@AntoniGawlikowski]

Hello Dr Lincoln, great video as usual! I have a question though: Could you elaborate a bit why the fact that neutrinos oscillate implies that they need to have some non-zero mass? This statement is frequently used but so far I was unable to find why that is. Thanks in advance!

[@alexv3357]

Because the ability to oscillate shows that neutrinos experience time. Massless particles like the photon travel at the speed of light and do not experience time; from their frame of reference, their entire existence no matter how long they live and how far they travel, happens all at once. Neutrinos must have mass because they can oscillate as they travel, which they couldn't do if their entire existence was instantaneous.

[@clancyjames585]

@@alexv3357 I think the observation of oscillation allows for up to one neutrino to be massless. Photons are massless, and their wave fields oscillate.

[@alexv3357]

The underlying electromagnetic field changes as they travel, but photons themselves are massless and timeless and cannot oscillate the way neutrinos do

[@linabrink2718]

Thank you Dr. Lincoln for explaining quantum physics to us. I really like your videos!!👍

[@lllbutcher]

Around 1:45 you show a chart where "Probability of being an electron neutrino" varies with distance. But what the probability is actually doing is varying with time. By drawing a horizontal line (anywhere), I see that there are several places where that line crosses the curve. Those are places where the probability is the same, but the direction and rate of change are different. I can't help but think that the neutrino is rotating in a 3-D "neutrino type" space with a rate which is different (but constant) along 2 axises. Like a precessing top. Then electronness is a projection along one axis. The curve is entirely different than what I would expect if a neutrino starts out as purely one type, then "decays" into a mix with an average proportion of each of the 3 types. What's the story?

[@Valdagast]

How does that square with conservation of momentum and energy? Do they also move at a superposition of different speeds?

[@PhilosopherRex]

that's a great question ... I'm no physicist, so have no answer ... but makes me wonder if speed superposition, then maybe that's why they are so hard to detect as they are are arriving and leaving the detector at the same instant - they are a smear in space! lol crazy stuff.

[@drdca8263]

Googling “neutrino oscillation conservation of mass” brings up a paper by Kirk McDonald which seems to kind of(?) say that there is a superposition of velocities? It says in footnote 4 of page 3 that “the notion of a single rest frame for oscillating neutrinos is doubtful”. It says that the idea is a bit sketchy for kaons as well, but that because the spread(?) of masses for an (oscillating?) kaon, is very small compared to the average of the masses, so it is a good enough approximation to say that there is a single rest frame for a kaon, but because the spread of neutrino masses divided by the average mass is more than 1, it causes problems. Personally, I find this to be a rather wild idea! Suppose we take, like, a frame which is in the middle of the distribution of velocities for the neutrino. Then, it seems to me (if I’m interpreting this right) like in that frame, the spread for the position of the neutrino should spread out arbitrarily far over time. That seems wild to me!

[@PhilosopherRex]

@@drdca8263 It's bizarre isn't it. What does this mean about space time and matter ... head is exploding.

[@ronenshtein7083]

Yes is the short answer. e.g. from a paper about neutrino velocities: "Oscillations lead to distortion of the νµ wave packet which, in turn, changes the group velocity and the distance νµ travels." As far as I understand it, when a neutrino is born, it's born with 3 different flavor components, each propagating at a different velocity. Their relative phase is what changes during the journey, so when you measure it at the end of it, you measure only one of 3 possible results.

[@Valdagast]

@@drdca8263 Yeah, how come they all arrive at roughly the same time from supernovae?

[@foxhound1008]

With all this morphing going on, and different masses involved, mass being an indicator of rest energy, are there any issues with violation of conservation of energy? OR, is that issue addressed with the uncertainty principle? However, if all the neutrinos leaving the sun are electron neutrinos, and they morph into a different neutrino, with different mass....where did that energy come from? This may have been addressed in the takeaways at the end of the video where is is stated that a certain neutrino doesn’t have a specific mass. If that is the case, what makes an electron neutrino characteristically different then the other neutrinos?

[@michaelcornish2299]

Another great topic, this one is mind bending. Is it a sign of something beyond the standard model?

[@Andrew-rl3uo]

Absolutely since it implies that neutrinos have mass, while the SM accounts only for massless neutrinos.

[@sapelesteve]

Another great video Doc! What's the story with Bose-Einstein condensates & how would their discovery give us a better understanding of the universe in general?

[@realdarthplagueis]

Dr. Lincoln: I have a question about black holes. As I understand it black holes have a few properties like mass energy, angular momentum and charge. Nothing (except Hawking Radiation) can escape the event horizon of a black hole, so the only thing we can feel at distance is the graviational field of the black hole. My question is this: How does it makes sense to speak about the charge of a black hole when the electric field coming from the charge cannot escape the event horizon? Or can it? I understand one can calculate that a black hole created from something with a net electric charge must have charge, but how does it become a property of the black hole?

[@k_tell]

Does the graph at 1:48 mean that different proportions of the solar neutrinos are electron neutrinos from one day to the next because the distance to the sun is changing as we move round the elliptical orbit?

[@p_square]

Sir, can you please answer my question Does mass shell conception and the transitions between neutrinos with equal masses are real and neutrinos with different masses virtual?

[@mhorram]

Out of curiosity, isn't it possible to determine the mass of the neutrino by observing the difference in time between the light from a supernova being detected and the neutrino 'storm' (that precedes it) being detected? I would think that we know the time difference at the point of the 'explosion' between neutrino production and photon production. If the neutrino has no mass, on earth we should detect the neutrinos slightly before the photons from the explosion. If there is a difference; but, with an 'unexpected' value, it has to attributable to the neutrino having mass. Relativity should tell us at that point what the mass would have to be for the observed difference time in detection. Even if the neutrinos are 'oscillating' as we detect them it doesn't matter. It is the time taken (i.e. difference) that is providing the mass determination NOT a direct measurement. A Shroedinger's Cat question. It always seemed wrong to me as presented; because, determining whether the cat is dead or alive can be determined by indirection. The cat gives off body heat and that can be detected by infra-red and other temperature measurement devices that aren't DIRECTLY connected to the experiment. If you get a cold reading there is only one conclusion: This Schrodinger's cat is no more! He has ceased to be! 'E's expired and gone to meet 'is maker! 'E's a stiff! Bereft of life, 'e rests in peace! 'Is metabolic processes are now 'istory! 'E's off the twig! 'E's kicked the bucket, 'e's shuffled off 'is mortal coil, run down the curtain and joined the bleedin' choir invisible!! THIS IS AN EX-Schrodinger's-Cat. Sorry for overwhelming you with science guy terminology but I want people to know that Schrodinger's cat died years ago. I think Schrodinger hated that cat so much he made him part of the Trinity test. Sadly, Schrodinger forgot that cats have nine lives so 'The Cat came Back".

[@nibblrrr7124]

Great video! Small criticism: The graphic at 5:37 is pretty confusing, as the distances between the 4 groups doesn't make clear which groups belong together. At first, I read it as two rows (all big; all small), like English text. A less orderly arrangement within columns, or a dividing line between them would help enormously. Also, everytime you use Schrödinger's cat as an example for superposition - instead of as a reductio-ad-absurdum attack on the Copenhagen interpretation, as intended - Erwin's ghost goes into a superposition of angry and sad.

[@GuyNamedSean]

I've been wondering for a long time exactly how/why particle and anti-particle pairs annihilate. What's going on there and why doesn't it happen in other pairs of particles?

[@virajkapani6159]

Particles and their anti-counterparts are identical except for their charge. So, if you take a positive charge and negative charge they annihilate each other . That is what happens there , the particles annihilate each other releasing its total energy. Well , it does not happen with other particles because they have different charges but not opposites.

[@renerpho]

The key is that charge is conserved. Take an e- and e+ particle. Their combined charge is 0, which is the lowest possible energy state of the electron field. This means that, if you combine the two then the electron field can get to a lower energy state - that of no particles at all. The same is true for the positron field. If charge wasn't conserved then all electrons would happily decay into photons on their own, but lucky for us, they can't do it on their own. Of course the energy is conserved too and has to go somewhere (it becomes a photon), but that's a different story. :-) EDIT: Regarding other pairs of particles, well, you can still get something similar. Take a pair of p+ and e-. If you combine them, you get a neutron (also conserving charge), while the original p+ and e- particles are gone. It's not that different from an e- and e+ turning into a photon. Luckily, in the case of p+ and e-, there are things that prevent them from combining under certain circumstances, which makes atoms possible (we have to thank the fact that the two have different masses). But the process does occur inside of an atomic nucleus, due to the weak force. Importantly, there is nothing that prevents matter/antimatter pairs from annihilating (the two have identical properties, except only for charge), while other particle pairs are usually prevented from annihilating by the rules of quantum mechanics.

[@RussellSubedi]

@@virajkapani6159 The charge couldn't be the only factor here, it might have something to do with spin as well. My guess is that an electron and a positron with opposite spin (+½ and -½) won't be able to annihilate, as the spin of photon is 1 but the resulting spin is 0, violating the conservation of angular momentum. I'd love an explanation here.

[@RussellSubedi]

en.wikipedia.org/wiki/Electron%E2%80%93positron_annihilation I didn't take into account that a pair of photon is created during annihilation. Now, the net spin of 0 can be accounted for by having photons of spin +1 and -1 each. I'm thinking this is what Don meant when talking about photon and anti-photon, but I'm most likely mistaken. I'm still confused regarding electron-position annihilation when both of them have the same spin, as the spin now adds up to ±1, which I don't see being split into two photons, unless this is a case where three photons are produced.

[@virajkapani6159]

@@RussellSubedi No the spin remains the same.

[@jauhueitang6879]

Hi, Dr. Lincoln, I have a big question for you. The rest mass of muon or tau neutrinos have a rest mass several MeCpV at least. The upper bound are 2 and 30 MeV, respectively. How could solar neutrinos of about 0.5 MeV be able to change into muon and tau neutrinos when they travel to earth. There is not enough energy for an electron neutrino to become an muon or tau neutrino. The flavor changing mechanism might be true for GeV cosmic ray neutrinos bit not for solar neutrinos. Do you a free with me?

[@hinkles73]

When you think of neutrinos as waves, the flavor labels (electron, muon, tau) don't match up with the mass labels (m1, m2, m3), so the wavelengths go in and out of synchronization as the neutrinos travel, so there's constructive interference one second, and destructive interference the next. This means that the neutrinos change flavor, which is exactly what neutrino oscillation is. Bingo.

[@superkamehameha1744]

Hi Doctor... what's the leading theory to why everything's here? Baryogenesis or Leptogenesis?

[@siddharthjana6140]

do proton and proton also emit photon when they interact with each other (when aren't so close for the strong nuclear force to act)?

[@narfwhals7843]

Yes. All charged particles do. If you look in detail at the protons it gets much more complicated, because of the quarks inside, but you get a good approximation by just treating them as positive, heavy, electrons.

[@EnrichedPu]

So nice to watch your videos! Love them all! Thank you Dr. Don Lincoln and Fermilab for making this possible! I have one question that slightly bothers me: taking into account that the Heisenberg uncertainty principle allows energy to be "created" for brief periods of time, wouldn't that mean that a neutrino (with very little mass) would be able to "get" this kind of energy for a short time (thus changing it's mass for some time) and then go back to its original status? If two neutrinos (for instance an electron neutrino and a muon neutrino) have similar masses, wouldn't it be possible for them to "jump" from one mass to another for quite a "long" time? (at least long enough to be measured). What do you think?

[@kylebowles9820]

Awesome details this episode! The particle interpretation is really breaking down on this one!

[@sreeshakv5405]

I like this channel. This is very informative, honest and simple. I learnt about atomic physics and got interested from you. Thank you sir..

[@mlqsquad533]

I have a question: What particles are protons anticipated to decay into? Why do scientists think proton decay exist? and in what field is it relevant? thanks in advance :D

[@RussellSubedi]

Is neutrino oscillation a function of distance or time (or both)? Does it depend on its momentum? Also, can you give us some numbers, such as difference in mass and frequency of oscillation?

[@Andrew-rl3uo]

The oscillation frequency depends all these quantities! The term is sin²[(Δm² t)/(4E)] where Δm² is the difference between the squared mass of two neutrino states. As neutrinos travel it can be seen as a function of time and distance interchangeably.

[@AliHSyed]

SciShow did an episode on this just yesterday!

[@RussellSubedi]

kzbin.info/www/bejne/pnrUZ2hqdrJ7e9k Thanks for the heads-up.

[@maheshp1010]

The contents are nothing alike although.

[@BothHands1]

yeah, i saw it! it was far more in depth than most scishow explanations, so i really enjoyed that they didn't excessively oversimplify things. it's definitely an episode everyone should check out.

[@xrokis3123]

subscribe to pbs space time dude

[@AliHSyed]

@@xrokis3123 oh I am, I was there even before the current host joined. 😎 To the best of my knowledge, there is no space/physics channel that has alluded me thus far.

[@StaticBlaster]

I have a question : Can you please make a video explaining entropy, information and energy and how they relate to black holes? Thanks Don.

[@x_abyss]

Hi Professor Lincoln, My question is, does neutrino oscillation have probabilistic relation with distance? If not, why didn't the Super-Kamiokande detect changes in solar electron neutrino concentration in an year-round experiment?

[@esperancaemisterio]

Thanks a lot for the videos Dr. Don! One question! Since the mass of the neutrinos are always changing, how would the gravity be if we had something huge, like a planet or a star, made only of neutrinos? Would its gravity be changing all the time?

[@davidfilo1123]

this planet/star will not exist because neutrinos aren't heavy enough form it

[@MooImABunny]

So, we know that up, down, strange, etc. all have definite masses. We also know that in a W emission, down transitions mostly into up, strange mostly into charm, and bottom mostly into top. We classify the quarks in terms of their masses, and as a result, their interactions are mixed, for example up has a small chance of transitioning into strange. It seems to me that neutrons and charged leptons do the same thing, with two exceptions: 1. Their masses are so tiny that for a long time we thought they were massless, and 2. their mass identity and their interaction identity are much more different than in the quarks' case. If this is indeed the case, I'd argue that it would be more straight forward to classify them by mass identity, so that the model would me more clear. A good pushback to this statement is that when trying to identity neutrinos in the lab, but identifying their interaction identities is easy, while measuring their mass is currently impossible, unlike with quarks.

[@Tutul_]

If we can't calculate the three mass, how did we detect that particularity ? how do me know that each neutrino has a proportions of the three ? and how do we know that each mass is that specific proportion of neutrino ?

[@jauhueitang6879]

How do you determine the ma of these three types of neutrinos? Do you determine from the quantum beating of neutrino beam? If neutrinos do not interfere with each other, the square of the complex wave function does not contain phase information or mass information.

[@guilhermehx7159]

is there some technological application envisioned for neutrino oscillation? Or for the use of neutrinos themselves?

[@photinodecay]

They are so small and light that we don't really have any way of containing them or using them at a physical scale just yet. But who knows what we will be able to do in 100 years. We didn't even know that neutrinos exist 100 years ago.

[@k.r.jester5406]

What are the ways neutrinos can be observed? Also, what ways can other particles be observed?

[@MusicalRaichu]

yes and how do we know so much about neutrinos when they hardly interact with anything at all?

[@Nada_fr]

Hello dr.Lincoln I love your videos I was wondering if you can recommend some good physics books ?

[@dachew57]

Hi. Dr. Lincoln, since neutrinos have mass, can they show down? Could they in theory travel at human speeds? If they did, how would they experience time, or, how would their experience of time manifest for changing identities?

[@Lucius_Chiaraviglio]

Given appropriate conditions, could charged leptons also oscillate? For instance, in a nascent neutron star, in which electron capture into protons to make neutrons has not yet proceeded to equilibrium (and might even be impaired by a finite rate of neutrino escape leading to temporary neutrino degeneracy pressure), electron degeneracy pressure could get so high (driven by gravitational collapse) as to be able to pay for the difference between the masses of electrons and muons, thereby allowing electrons to oscillate directly to muons without producing any neutrinos?

[@Eliphas_Leary]

Are neutrinos part of any process/interaction with other particles or do they just fly around after being created?

[@andyiswonderful]

As always enjoyed your video. I have two questions. 1) You mentioned Schrödinger cat, and that we can't know its quantum state until we open the box and observe it. But, what if I hear the cat meowing inside the closed box. Did the cat determine its own quantum state, or did I, since I inadvertently detected its state? Since the cat meows before I hear it, seems like it determined is own quantum state. 2) The graph of the oscillations of a system starting with 100% electron neutrinos was amazing and surprising. As a chemical engineer, I would have thought the system would come to some equilibrium between the three types of neutrinos, just like a chemical reacting system normally does. So, why doesn't it? Can physicists write the rate equations for the different transformations? Maybe it is a limit cycle, which is rare in chemical kinetics, but does occur.

[@MusicalRaichu]

Don presented schro's cat only as an analogy to help you understand the quantum nature of neutrinos. Schro's cat is not a real experiment or anything. You can't have a cat in a quantum superposition like that.

[@angelomarcio8382]

Dear Dr. Don Lincoln, thank Very much for your excellent videos! What is the rarest matter in the universe, antimatter or exotic 2nd / 3rd generation matter? Which one is the "more dangerours" for the ordinary matter?

[@eyle6839]

Hello, dr. , my question is, if the neutrinos can have different masses at the same time, does that mean that their gravity would also be "different" at the same time? love your videos!

[@psmoyer63]

Well Dr. Don you did it this time, my mind is truly blown. I had to watch this video a 2nd time to just to understand what I didn't understand! You're right, Schrodinger's cat's got nothing on neutrinos.

[@SerGio-xs9ss]

Minute 1'58: What is the ratio between the two frequencies ? It appears to be exactly 16. Or is it different ? Thank you.

[@williammason632]

Hey Dr. Lincoln, I have a question about super symmetry. If charged particles have an anti-particle could an anti-particles be an example of some kind of Symmetry? kip mason

[@torbjorn.b.g.larsson]

I was linked to the neutrino oscillations part but started in on "other questions" because it is interesting to see what questions people have. The "can combine QFT and SR" part is rarely seen but likable of course, but then the "can't combine GR and QFT" part isn't quite right. It is only at Planck energies that GR (rather, the QFT of gravity) has an infinite number of parameters that needs to be observed.

[@calebpoemoceah3087]

Could the neutrinos be oscillating with (wimps/particals in a wave motion), if so when the nutrinos oscillates is there vacuum pressure produced?

[@oldpariah]

Is momentum conserved throughout neutrino oscillations, and if so, does velocity vary with these mass changes? Does acceleration after mass reduction occur spontaneously without force?

[@oisnowy5368]

I assume experiments will have been done to estimate/measure neutrino masses and while they might be relative... I assume we at least have certain maxima, top estimates of neutrino mass. Do we?

[@Andrew-rl3uo]

Yes, experiments that study oscillation can measure the fractions that describe neutrino mixing and their mass difference, while experiments like KATRIN aim at measuring the neutrino absolute mass. Finally cosmological observations put an upper limit on the sum of the three neutrino masses around 1 eV/c² (so far).

[@LupusRutilus]

A wave can travel across the sea but consists of completely different water molecules on the other side. The wave "moving" is just an illusion of changes in amplitude. Does this also apply for field theory? So if I move my hand from A to B, it is just field waves which propagates to the new location, creating a new hand at position B?

[@PilgrimEnge]

Is the weight of each neutrinos a constant (but undeterminable before measuring), or is the weight of the neutrions themselves a variable? Could it be that their weight is bouncing "up and down", and that we just don't know and just can't tell?

[@harthur2010]

Cool video, I wonder where the engery in a neutrino goes/comes from when they change mass? Interesting note, one of my sons (A physics student) was once invited to have lunch with Arthur McDonald (who won the nobel for discovering neutrino oscillation) when he was visiting his university. He was thrilled / humbled by the experience.

[@rigolozio]

hello Dr Don, i recently read that half the matter that should exist in the universe is missing, does that mean that the universe bigger than what we observe or did i understand it wrong?

[@samuelrodrigues2939]

Hi Don.. how one can tell that these neutrinos are of different identity if one cant tell their masses.. or if one can tell the mass after measurement how does one know what was the origin (as neutrinos could have oscillated)

[@TheNorgesOption]

Could it be that fluctuations in the various fields in empty space, briefly transform normal energy into virtual particles? It would take far less of a fluctuation from a neutrino then other particles, so therefore can either pickup or emit energy more readily?

[@elliellama5629]

How do you know that there are three different masses of neutrinos if they cannot be measured even approximately? What's more, how do they know they have mass? What principles support the answer? (Ellie, philosophy major at Cal State LA)

[@m.a.3322]

Love your videos, sir. Thanks for educating us!

[@srijandas73]

Hi Don,I have been following your and FERMILAB work for some time and have grown attracted to your work with particle accelerators . So can you please tell me more about it. Also how can I make a small particle accelerator?? Thank you!

[@mheermance]

Does the weak force enable neutrino oscillation, or some other mechanism? Also, particles with multiple possible masses is mind blowing.

[@negiamerica]

Dr. Lincoln your videos are awesome. Thank you very much. I am Italian and I do, sometimes, order a capuccino as "dessert" after launch at the University Cafeteria. They used to give me surprised looks too. But well, I guess it's not so uncommon after all, right?

[@sankalppentam9797]

can you make a video about the decay of fundamental particle ?

[@gwyllymsuter4551]

Fascinating and familiar waveform produced by neutrinos. Its Amplitude modulation. Could the neutrino's interaction with other fundemental forces cause the carrier energy modulation?

[@xrokis3123]

hello Don what do you think about neutrinos decaying into a dark matter or dark energy? if neutrinos have mass but not interact whit matter it might produce the dark state particles

[@atomicripper239]

Dr Don Lincoln,if neutrinos can change into other neutrinos, does that mean that there is one quantum field for all the neutrinos?

[@photinodecay]

No, there are three fields for neutrinos 1, 2, and 3, and when we observe an electron, mu, or tau neutrino, we are actually detecting a superposition of those three fields.

[@brogant6793]

Rahul Jain I have a general QFT question similar to this (if you wouldn’t mind answering) how does the electron field for example communicate with these neutrino fields when an electron and proton undergo the weak interaction to produce the correct electron neutrino to conserve lepton number?? Does this imply that the electron field is connected too all 3 neutrino fields at once to obtain the right superposition

[@photinodecay]

@@brogant6793 well, I'm no expert on QFT's details at all, but I do know that each field interacts with the other fields, which is what causes the "interactions" between particles, and the form of those interactions reflects the conservation laws by preserving corresponding symmetries in the wavefunctions

[@Henrique-hl3xk]

A question: I know energy is a function of the frequency and it's quantized, but is there a frequency that "doesn't exist" because that are no electrons in any atom or molecule that can change by that amount? If photons interacts with particles and change their energy level (and all atoms have specific spectral Lines) does that mean that every possible energy level exists in the electron cloud? For example, If a photons of a specific energy "hit" an electron, It change it's energy to a next "level". How can every possible frequency be available? Greetings from Brazil!

[@BothHands1]

your IOU image got a good giggle from me

[@unvergebeneid]

Together with the recent Scishow episode on neutrinos, this video made me realize that neutrinos are _way_ weirder than I thought.

[@hinkles73]

By the way, Lisa Randall's book Dark Matter and the Dinosaurs was mentioned at a certain part of John Butterworth's Atom Land. His book Most Wanted Particle is also mentioned. It tells you about the star of the Standard Model, the Higgs boson.

[@haidarasifi6169]

hi Dr. are these behaves of neutrinos related to quantum entanglement?

[@frankkubrick865]

Would there be an infinite amount of particles that make up quarks? For example if we discover what quarks are made from could we go on forever finding smaller and smaller particles?

[@sdz9081]

one of the goals of the research on neutrino oscillation is leading to teleporting materials after some years.is it?

[@jovialdunbird6653]

Every episode is a mind melt 👍😁

[@sc0or]

Do we see traces of different annihilation processes in a microwave background? Like +q -q, +p -p, +e -e. These must be absolutely different energies. If yes, do we find the same (or similar) structures in all spectrum?

[@palmercolamarino4548]

Dr. Lincoln, you have seriously risked to loose me as subscriber after you've confessed the "cappuccino after 11.00am" crime. 😂 Your are forgiven. Your videos are too good to be missed. (I am sure you may guess my nationality.)

[@drdon5205]

It's your country's fault for making such a foamy and delicious drink.

[@ishaanvohra2311]

Dr Lincoln: If the existence of right handed neutrinos and left handed antineutrinos (sterile neutrinos) were ever proven, how would this affect the standard model? Could they be candidates for dark matter particles?

[@theultimatereductionist7592]

6:58 LOL! Now that's a SOLID SIGNED CONTRACT if I've ever seen one! You can bet your neutrons he's going to keep his promise!

[@vivekprakashyadav7043]

what's outside the universe means what do we know about it is it different ,the physics there works differently or the time is in may be reverse direction and entropy is decreasing

[@rJaune]

Since neutrinos can change their mass, do they always travel at the speed of the heaviest mass? Or can they speed up if they get lighter?

[@guilleteru]

Okay, I have 2 questions regarding this episode: 1- Subatomic particles like neutrinos or electrons are seen as a "wave" of probability until they are observed. What qualifies as an "observer" (could it be that schrodinger's cat can act as an observer for the atom decay?)? 2- Do Neutrinos have spin and if they do, do that spin change when the neutrino changes its identity?

[@derschimpanse8399]

Neutrinos are fermions so they have a spin of 1/2. So every neutrino has the same spin. While oscillation they doesn't need to change spin.

[@ahsanrizvi2205]

Comment before watching full video

[@Abdul_the_next_door]

We often get to read words like "hot" and "cold" in the context of big bang. We can understand that hot refers to the vibration of particle in regular matter. But what does it mean by hot and cold in the early universe when atoms have not yet formed?

[@steelhammer103]

Has there been any theoretical possibilities proposed in which all three neutrinos types come from a single particle that exists in a high energy state?