Fermions and Bosons

[@GugaCoder]

Whenever I struggle to understand a concept, I head to your channel, and then I get it. I'm a huge fan of yours.

[@rilum97]

Without your channel, i wouldnt have no clue about this fascinating subject of physics. Thank you Sir Lincoln and Fermilab for teaching us particle physics !

[@MarianneExJohnson]

I love how Dr. Lincoln always has an appropriate t-shirt for every occasion.

[@nikhiljoon1166]

What's on this tshirt

[@cuco-kr3ee]

@@nikhiljoon1166 we will never know because this vid is posted in 2017

[@zodisgreat4510]

I absolutely love these videos. More please. More. Thank You Fermilab and Dr Lincoln.

[@bruinflight]

Zodis Great TOTALLY!!!

[@dongato6838]

So those cats can be classified as FUR-mions, right? ...I'll see my way out.

[@dongato6838]

eh6794 - I was actually gonna go with Fur-meowns but I though I'd start light. Lol

[@atimholt]

Thanks for the new mnemonic! Are puppies bow-wow-sons?

[@dongato6838]

atimholt - Fur-MEOWns and Bow-wow-sons...I think we got something here! 🐱🐶🐈🐕

[@keithwald5349]

Be sure to tip your waitresses generously, ladies and gentlemen.

[@rhmb1019]

Only Schrödinger’s cat can be classed as a fermion

[@Biogenesiss]

Your videos is really helping me getting through times of high anxiety. The tone is light as a feather, there is cool jokes as this spinning head, and Don is a charm quark. And all this while I learn about things I love so much. Thank you, Don. It's great what you're, doing here.

[@toushei]

Thank you for explaining that the spin of particles corresponds with its wavefunction.

[@martinpiekarski1512]

Yep, many materials on quantum physics fail to explain that properly.

[@kamronchance825]

I've never heard anyone explain this concept so well!

[@paulmichaelfreedman8334]

0:50 probably one of the most valuable photographs around for scientists. The sheer number of giants in this pic is Epic!

[@sweepingdenver]

Read Isaacson’s Einstein biography. He goes deep into what happened at these gatherings!

[@MasonDixonLine1]

I was today years old when I finally, after a full year, understand what spin means. This whole time the answer lies in the units!

[@DicerX]

Thank you Doc! Love your videos, I am a new subscriber and honestly I am just amazed at how much you give insight to. Thank you once again.

[@ashwinisidhu]

Thanks for these informative videos. These help me in keeping abreast of the latest in physics.... It used to be my favourite subject in college.

[@leventgonul2035]

İ like to thank you, your explanations are so clear that even a guy dumb like myself can understand. I will watch your all videos. Thank you again.

[@1q1q1q1q1q1q1qw]

It is a nice introduction, you have a calm way to talk about it 😊

[@lufebeta]

can you make a video about what spin is? thanks for the wonderful videos you make...

[@frankschneider6156]

+Luis Betancourt It's a quantum mechanical number (just like n,l or d), WITHOUT further meaning on a macroscopic level. Especially does it NOT mean, that something (eg an electron) is (literally) spinning clockwise/counter-clockwise or left/right. that's just an explanation given to make it more intuitive, although the magnetic moments might support this suggestions. The only important thing is that both fermions (in this case electrons) are not identical in all quantum numbers, hence the difference in spin wen occupying the same space. It's best to treat it like a number / unknown property without thinking too much about it and what it might man in a macroscopic world (trying to interpret quantum mechanics usually only leads only to trouble and weirdness (just think of quantum eraser experiments). So it's best to avoid all interpretations in QM and focus on the math, because that always results in the correct answer).

[@lufebeta]

well, that's the point, it's challenging but fascinating..

[@SpaghettiToaster]

Frank Schneider That's not true at all. Quantum spin has all the properties of a classical spinning motion, including the preservation of angular momentum etc. It is completely right to think of it that way. That is how you understand things instead of just describing them abstractly.

[@RoboBoddicker]

Particles have angular momentum, yeah, but it's wrong to think of them as literally spinning around an axis. Experiments have put maximum bounds on the size of the electron, so even if it does have some tiny volume, it would have to be spinning faster than the speed of light to maintain its observed angular momentum.

[@NotApplicable555]

Frank Schneider thats not at all true. Spin has very macroscopic operations. Its magnetic orientation, which is how its measured.

[@hunkarun]

THANK YOU. Very clear and comprehensible explanation. Brilliant stuff. 👍👏👏👏

[@bikashthapa7316]

This is magnificent to understand fermions and boson

[@bruinflight]

Yay yay yay!!! I LOVE this channel!!! Seen every video like 10 times! More please! You guys rock!

[@DarkHorse70]

Forgive me if this is a dumb question, but when you use the word spin, as indeed you sometimes use the word colour, do you really mean that it spins, of is this possibly just a name of a property that could lurk in and out of one of the 11 dimensions that could exist? If this spin is real, is it something you can actually observe, or do you only observe the nature of a property? Thanks for the video, other than that everything is pretty clear.

[@oromhal]

Great video, thanks a lot!❤

[@soapyseth]

Dayummmm that introduction is fire. “And the list goes... well... on.”

[@SureshPakkam]

Dr. Lincoln, I came across your video on Inflation. We have devised the inflationary expansion to reason out homogeneity in the early early universe. It is also widely agreed that the universe was at a superfluid state at the crazy High temperatures. Is it possible that all elementary partials were behaving like Bose-Einstein fluid at high energy state. Would this help explain the homogenous state of the early universe? I am sure I am missing something fundamental...please clarify

[@SureshPakkam]

ScienceNinjaDude I did some digging and came across a paper that describes about the BEC non locality nature. I would be interested to hear Dr. Lincoln's response about this paper and the possibility of Bose Einstein fluid to explain both non-locality and homogeneity instead of inflation. Paper: Bose-Einstein condensates and EPR quantum non-locality F. Lalo ̈e Laboratoire Kastler Brossel, ENS, CNRS, UPMC; 24 rue Lhomond, 75005, Paris, France November 2, 2006

[@PhysicsHigh]

nice job - Like the puppy and cat analogy

[@MisterTutor2010]

@6:12 So fermions are cations :)

[@adastra6083]

Super-hyper great lesson. Thank you!

[@nabilahahmadkamal6325]

Thank you Dr. for your video. It really helps me to understand physics better.

[@saylagirl380]

Thank you this really helped with my Physics assignment.

[@TiagoGMeurer]

That’s a wonderful explanation, for sure! Appreciate it so much. ✨🍎🥂

[@craighearps4157]

How did you get 1.2x10^-34 j/s? I always thought it was 1.05 etc.?

[@jessstuart7495]

Can you do a video explaining in more detail of what spin is? Where it comes from (Dirac Equation)? How it is measured? And why it imparts certain properties onto particles?

[@Salmanul_]

The list goes "on". Ah, I love this channel.

[@rsmit2797]

I do like these videos. However, if h is about 6.63^-34 Js, then the Reduced Planck Constant should be about 1.05^-34 Js? Am I missing something?

[@VEVOJavier]

3:22 what are those little things crawling around at the bottom left?

[@aran_tripathi]

Ok, this was an example. Not being mean or anything, but if you were focusing on the small ants,(yes, they were ants) you were not paying attention to the actual point he was trying to get through. Just a heads up!

[@andrewknorpp9415]

they are a new class of particle, the madogans! they are the smallest and most tightly grouped particle known to man.

[@richardcarter5314]

From 0:40 to1:05 there is a photo of a group of scientists. What was the occasion and can you please identify them. And perhaps their field of work too! Many thanks if you can and do!

[@CarinaPrimaBallerina]

The puppies got me distracted ❤ , but I still learned a lot :-)

[@anteconfig5391]

This was exactly what I was looking for. Thank you

[@tresajessygeorge210]

THANK YOU PROFESSOR LINCOLN...!!!

[@1q1q1q1q1q1q1qw]

However I try to learn quantum statistics for those particles and am wondering what’s the exact reason for Pauli principle you mentioned it have something to do witch symmetry of wave Funktion; but I don’t know why this forbids more then one fermion in one explicit state

[@amdenis]

There was a confusing section for many who have little background. In the beginning around 2:00 in, you assert that fermions have 1/2, 3/2. 5/2,...spin, but then later around 4:30 you mention that they do NOT have 3/2, 5/2,...

[@PriyanshuKumar-ti9gv]

Didn't understand how two particles can be at the same place,I mean in very very microscopic measurement there is always a chance that any two particles can't be at the same place? To be more clear,I had seen this explanation for fermions on wikipedia: "no two fermions can share a quantum state (which includes position in space), if they have the same quantum numbers, such as spin." So,how can position in space be used as quantum state?

[@evalsoftserver]

I believe Pauli Exclusionary Principle can be violated because Superposition and Spooky Action at a Distance is real and it also must Violate E=mc2 and faster than light information communication, Fermi Dirac Distribution Fermi energies, Ultimately implies that the Wave function, Heininberg Uncertainty, Planck's Constant, And the Cosmological constant is incorrect

[@georgeraviable]

it took me 5 years to pass this paper called Fermions and Bosons in SM, but now i am fully understand about this particles, Bosons are the particles that belong to Bose Eisenstein statistics and Fermions are the particles belong to Fermi Dirac statistics, both of them are belong to Quantum statistics and other one is classical statistics whic are called classicals, they belong to Maxwell Boltzmann statistics, for eg: gas molecules, Bosons eg: photons in cavity, liquid helium at low temp. etc, Fermions eg: electrons in metal atom, stars whose atoms are getting compressed(white dwarfs, neuton stars etc.

[@jsykes1942]

There. My unasked question got answered at 3:25 in this video - an unlimited amount of bosons can exist in the same place at the same time. So if a particle does not experience time, like a photon, then it would not experience space either. This may explain why two entangled particles instantaneously respond when only one of them is affected. They are not really separated by time or distance. They exist in the zero-dimensional roots of our universe and can appear to be in two separate spaces of a four dimensional universe, when they are actually not.

[@sanchitgarg2745]

Um...Sir I have a question that if all the matter is made up of energy, so how can electron and proton have charge and can attract each other, is that mean energy is classified in positive and negative charge too?

[@richd21t]

Happy New Years FermiLab

[@NGC6144]

Among what I don't understand about the Plank Constant(in relation to Spin) is if it's the quantum of action than how can particles possess a reduced value(h-bar) and further fermions have 1/2 of that reduced value?

[@zodisgreat4510]

NGC6144 my understanding is that they use, find, extract, extrapolate, deduce or construct a unit that normalises as much of the data as possible.

[@nr68-68]

I have a question about bosons: when it is said two or more bosons occupy the same quantum state does that mean they occupy the same 3-d space and if that is true do they remain discrete entities or do they merge into one “body”. I really do enjoy your videos it makes things so clear, thank you for making them.

[@KohuGaly]

I wonder, why the pauli exclusion principle holds? Shouldn't 2 stacked fermions simply be equivalent to boson with spin 1?

[@stydras3380]

KohuGaly because they cant be stacked ;D

[@KohuGaly]

yeah I get that, but why?

[@volkryn]

To visualize source of Pauli Exclusion, imagine particles as their wave functions. Since Bosons have symmetrical wave functions (integer spins), they can fit together by multiplying wave and don't need to apply any force to do that. It doesn't change their spin and any other fundamental property, just amplitude of wave function x number of particles in the same place. Fermions in other hand, have anti-symmetrical wave functions, so they can't fit each other. If one would force them, it probably would result with change of wave functions destroying original particles and produce by random chance of interference between wave functions completely different particles. I guess that's happens in particle colliders like LHC, when quarks are smash together and produce completely different particles like Higgs Boson.

[@chris_thornborrow]

it seems to me that Paulis equations were an attempt to explain the observed data (arrangement of electrons in shells) in terms of quantum properties. His equation results mathematically in a consequence (the exclusion principle). So the principle is derived. Neither the equations nor the principle attempt to explain why this occurs. As the equations explain the data, a consequence of the equations is that two co-located electrons can only vary in one quantum property - spin. One would have 1/2 the other must have -1/2. I think this would result in destructive interference of their wave functions (mathematically at the very least).

[@KohuGaly]

I am sorry guys. I'm receiving the notification to your responses but the comments don't show up...

[@chaiguy1337]

2:48 Can someone help me understand the x-axis that is antisymmetric here. I'm guessing y is probability, but is x related to time or space or both? And does this by chance have to do with a photon (a boson)'s time-reversibility due to it not having mass and moving at the speed of light?

[@brianswelding]

Excellent job, thank you! I understand much more clearly now.

[@Tadesan]

Whoa at the colorized Copenhagen convention photo!

[@hafizajiaziz8773]

It's Solvay 1927

[@papinkelman7695]

I am a fermion person

[@georgeraviable]

your selfish

[@dominickarturi3075]

Aren’t we all really 🤔

[@Turissss]

@Fermilab, What is the wave function about, how is it constructed, what are the parameters on x and y?

[@Importman2009]

BTW the reduced Planck's constant is 1.055x10*-34 J.s. Oh, and I love your videos.

[@pabloagsutinnavavieyra2308]

I was wondering what happens with spin when we analize systems more comolicated than (what we call now) fundamental particles. For example I have seen some papera and presentations claiming that an atom or even a molecule hve an integer number of spin. Does the Pauli's principle apply here? If so how? (Because it seems REALLY counterimtuitive) Or why not?

[@aaronsaunders6974]

The reason I’m interested in Bosons is bc of Einstein. And I stumbled upon *Joule* while learning about _Joule’s Law_ during being educated about electrician work.

[@shadow404atl]

Another well done video. Thank you!

[@Rando_Shyte]

Actually I would say "78 kilos" since Ive been spening most my life living in a metric paradise

[@neoc1121]

You only need "ok" and "too much" actually

[@andrewroberts5988]

Then why not stay there and make your own videos? Jesus Christ, why do these stupid metric system rants get to the top. Who cares where you live? Find something useful to bitch about. Get some fiber, move out of your parents' basement and come up with a useful thought. Don't wear out your Dvorak keyboard telling people how much better you are than they are.

[@TheDruidKing]

In Scotland, milk is sold in 500ml cartons but pints are bought at the bar. It makes no sense but no one gives a crap.

[@eliduttman315]

In the U.S., carbonated soft drinks are sold in 2 liter bottles and milk is sold in quarts. Metric actually is the law of the land in the U.S., but few citizens care and the bulk of the populace merrily goes on using Imperial units. Metric is the norm in matters automotive, where internationalization has occurred and (of course) profit rules.

[@innocentsmith6091]

US Customary, you mean. Imperial was the British system which was codified after 1776. That's just a pedantic gripe of mine though. But yes, all of our units are defined in terms of SI units. Anyway, there's nothing special about metric. You could add prefixes to represent powers of ten to any measurement system, and you can define any unit in terms of physical constants. Metric started out with poorly defined units, like the meter being one eight-millionth of the distance from the equator to the north pole or whatever. Hell, the kilogram is finally getting redefined in terms of the Planck constant instead of the International Prototype Kilogram next year. Metric is only standard in physics, engineering, and the military because France had sufficient influence at a crucial point in the history of science. There's no reason to fix what ain't broke, but something else could have been not broke if history turned out differently.

[@josephlamanna5969]

I am somewhat troubled by the idea of constants. OK so I get that pi is the circumference of a circle divided by its diameter, but other constants seem to me to be fudge factors to make the mathematics work(?). Like, how can the speed of light be a constant?

[@XAATIF]

Pardon me for this ignorant question but if two fermions cant be at the same place at the same time, then why do protons and neutrons have two up quarks and two down quarks? @Fermilab

[@sent4dc]

I was always confused over this term Spin. Can someone please explain it -- when we're talking about a spin of a subatomic particle, is there something that is actually "spinning" there, or is it just a name? Kinda like "colors" in the names of quarks.

[@pedrowirti2031]

I really feel there should be more videos about HOW this discoveries were made, how can we know and why we came to study such things. For me, It would be much more interesting than to know all this information with not much context to it. For instance, why does every force need a particle? How do we observe this particles, how did we discover them? How can we know their spin?

[@djgruby]

This is fascinating!

[@hrishikeshmavily5533]

The video was awesome,i do have a question though Let's say there's a type of fermion with max spin value of +3/2 so there can exist the same type of particle with spin value of +1/2 ,but then we know that electrons have A spin value of +1/2 too, assuming the characters of the electron and the weird particle with max spin value of +3/2 have the exact same properties(except spin) how can we distinguish them?

[@sydhenderson6753]

There do exist fermions with spin +3/2; they consist of three quarks of the same type (you can' have that with spin +1/2 due to the Pauli exclusion principle), or as an excited state of a fermion with spin +1/2. The excited states have VERY short half-lives. As far as we know, there are are no fundamental particles with spin 3/2; the ones I mentioned are composites of quarks.

[@cubedduckredman9568]

I love how he's like the chef john of particle physics

[@elnuraliyev6603]

The "On" Punwas absolutely hilarious!

[@marinaldobruno4864]

The best science channel ever

[@XEinstein]

3:41 WHY can fermions not be in the same state? The Pauli exclusion principle just gives the mathematical framework how to calculate their states, but it does not explain why. I understand that this is a metaphysical question, but I'd really want to understand the why rather than the how.

[@Harry351ify]

So, it seems that the smallest spin possible is 1/2 and everything else is integer multiples of it. So why do we stick with 1/2h instead of introducing a new unit which equals half a Plank constant? Also could this be because of an underlying physical structure yet to discover? Something that quantizes the spin?

[@nmagko]

Pramod Herath, it makes sense, if 1/2h will be a new unit scale maybe we will get a binary scale like computers... higgs 0, fermions 1 (before 1/2), photons 2 (before 1), graviton 4 (before 2) and so on?

[@nyx211]

3:36 And therefore, singularities don't exist at the center of black holes.

[@gaaraofddarkness]

Ache se samjhaya hai sir... Thank you

[@Skumar-rg4hd]

Sir I have a doubt spin of these particles. Spining is actually happened or not of the particles? Some say spin is intrinsic property mean we have no idea about the property of spin, but the result is know, in case of fermions when passes through N-S pole magnetic field some fermion deflect N side some S side. So from this it is concluded that fermions have "some intrinsic " property due to which this happens. But with regards sir in ur video u say that particles spin around them like earth spin around its own axis. Plz help me to understood does spin mean general spin of particles or something else whichi we can not know, but we only know about the effect caused by this property.. Also physically what is meant by integral spin and half integral spin? Sir....

[@amilom007]

can you please explain how you detect the spin and other properties of particles

[@ranjan1989able]

Prominent Indian physicists say that naming of the 'God particle' Boson after Indian scientist Satyendra Nath Bose is the biggest honour. The reactions came after Britain's Peter Higgs and Belgian Francois Englert won this year's Nobel Prize in Physics for their work on the 'God particle'.

[@reecewelling7968]

these help so much for my work!!!

[@MojoJOJO543]

This is a great video.Thank you

[@davelowinger7056]

do they spin different directions right turn be a positive molecule and left negative molecule or vice versa

[@davelowinger7056]

is spin a function ?

[@motorhead6763]

OK yet the EPR detector measures spin of positron electron . What methods was used to determine spin ? I am engineer who actually worked at BNL and moved the bubble chamber where omega minus was discovered . I am not a physicist. A lot of people ask this question on spin and how it is determined.שלום

[@qlifee]

I love your videos, and I love physics ❤

[@robson6285]

Is spin (of say a photon) related to the polarisation (of that photon? Or of an em-"ray" or em-field "carried" by that photon? Or how should i see that, If a photons polarisation and spin are indeed the same or related (or what&how)?)?!

[@evalsoftserver]

I believe that the Force carrier of Particles and Wave function is incorrect , the photon boson and fermions exsist Olny thru a Field and the Orientation of this Field determine the Particle or Forces characteristics

[@LovelyAlanna]

are these bosons and fermions actual particles? or are they just energy fields? I don't understand much of this, and it seems to me that everything is just energy

[@jollygroup1757]

What is smaller than fermions. What are strings in string theory made of ?

[@FrancoisBothaZA]

Like the others, I also want to know why it's called spin. I get that it's only an analogy, but what makes it seem like spin?

[@michaelsommers2356]

For one thing, ℏ has the units of angular momentum.

[@kyrios0028]

Please help me on this, Dr. Lincoln. Earlier part of the video says that the bosons have integer spins and that fermions have half spins and specifically mentioned 3/2 and 5/2. But then latter part says that 3/2 and 5/2 spins are not possible. I am confused.

[@shivram6622]

Nice videos. Doing a great job....

[@IkeChiu]

Thank you. This video is very helpful.

[@manoramasonare480]

I loved this vdo😍 nice explanation

[@wyllomygreene7700]

Cute cat video! :D Ooooh! And puppies too! Too cute! Must watch!

[@wyllomygreene7700]

ScienceNinjaDude Oh he is, just didn't want to make him blush ;)

[@glennbrandimarte61]

Why do you say, at 2:02, that "fermions can have a spin of 1/2, 3/2, 5/2, ...", while at 4:30 you show that fermions can NOT have spins 3/2, 5/2?

[@davidstefanboriceanu5004]

Glenn Brandimarte None in the STANDARD MODEL have those spins. There are more particles beyond the model.

[@marson68able]

If my physics teach could teach like u, that would be too great

[@MostlyIC]

what's missing here is an explanation of why whole spin and half spin particles are so different, I've read the explanation from a couple different sources but still don't really understand it, so was hoping Dr Don had a way of explaining it that would stick, maybe there's another video, ...

[@burningsilicon149]

Can 2 fermions some how combine their spins to make a boson.

[@AFROJOE2323]

Manipulating Fermions in relation to Bosons would be an interesting experiment. I would want to play out some outcomes of Slowing Fermions to a slower turns in a controlled environment :o

[@justindougherty5265]

What if subatomic particles are the fabric of reality or part of it?

[@justindougherty5265]

Those are the only things to have an influence outside of a black hole. Higgs bosons anyway. Hey wait if light can be a wave and a particle but not when being watched.... Does that mess up studies on stars and black holes cause there's always someone looking at them.

[@jennifernapoles3026]

Amazing video!

[@duncancampbellauthor]

This was a good try ... but it kind of spun out of control at the end ... 😂😂😂 Seriously? Excellent as always!

[@EyeOfAllah]

It would be interesting to create a Sci-Fi movie showing particles on a different planet with unusual properties.

[@johnstapleton9988]

Marie Farbar Come to Atlanta! Let's do it! I'm so sick of zombies... .

[@AbuSayed-er9vs]

Why there is Pauli's exclusion principle at all?Please make a video about the deepest meaning of pauli's exclusion principle for which the all matter was made at the first place?

[@DaTurdburglar]

Abu Sayed im not qn expert but from what i understand, pauli exclusion is what it is because energy exists as direct quantified amounts that are stable. theres too much repulsion if electrons occupy the same energy state

[@cortster12]

How can gravity have a force carrier if gravity is a geometric property of space-time? Can gravity be both a geometric property and have a force character? If so, how?

[@cortster12]

+ScienceNinjaDude Hence then I've come to a deeper understanding by thinking of all reality as intermeshing fields, where particles are just excitations in said fields (yes, I technically knew this, but I never really incorporated it into how I think about things until I watched a lecture a few days ago). Which, as I've come to understand, is the correct way of looking at reality.

[@shub00_]

I dunno why I am watching it.I am high school student but still loving it and giving me headache at the same time

[@DilmiKarunadasa]

thank you sir this was really helpful