Quantum Computing – The Foundation of Everything – Extra History – #1

Quantum Computing – The Foundation of Everything – Extra History – #1

The year is 1927 29 people gather in Brussels
to discuss physics 17 of those people
will eventually win a Nobel Prize and for a few short days in the middle of Leopold Park They will wrestle
with the smallest question or perhaps the biggest one to ever face mankind The question at the foundation
of everything. [intro song] For those few days those 29 physicists wrestled
with the question of the quantum determinancy and whether our world
at the minutest level operates
as a fixed system or merely as a group
of probabilities Their question stemmed from one
of the oldest problems in modern physics, the problem of light For nearly three centuries since Newton wrote
his famous treatise on optics Physicists had debated
whether light was a particle or a wave in 1803 this argument was thought
to be put to rest by one of the most beautiful
and simple experiments ever created the double slit experiment Okay, think of two buoys
bobbing up and down in the water as the waves spreading out
from these buoys hit each other and overlap They interfere
with each other if the peak of one wave hits the peak of another they’ll amplify
and become a bigger wave Same with the troughs but if a peak of one wave
hits the trough of the other they’ll just flatten out they’ll combined
back down to nothing. A man named
Thomas Young said, Let’s take that principle
and apply it to light And so he did
the simplest thing imaginable he took
a monochromatic light, to make sure that all the light
had the same wavelength and he shone it on a partition
with two small slits cut into it If light acted
like a particle he should simply see two columns
of light on the wall on the other side But if light was a wave then the waves coming
through each of the slits should interfere
with each other amplifying and cancelling
each other out in places And he would instead see a weird pattern
of bright and dark lines as a result And as he expected he did indeed see
that funky pattern and that was that. The particle theory of light
was done and dusted he’d solved
the dang thing Now everyone could finally move on
to talking about just how smart he was But then physicists
in other labs found something strange
in their own experiments They found that when light strikes
a material it can force electrons
to spew out of it this wasn’t that startling but the way it happened
was all wrong and definitely not how it should have happened if light was the continuous wave they’d believed it to be Then in 1900 a man
named Max Planck came up
with an equation that fit it made sense
of what was happening But as Planck himself
would later say it was an act
of desperation It went against everything
he thought he knew The only way he could get
all of the math to work was by treating energy as something that could
only be absorbed or released in discrete units How could this be?
He thought. How could energy
not be continuous? How could it not be a flow? He had no idea, but then this fellow named Einstein took
Planck’s act of desperation and ran with it He declared that light itself
was quantized That
in many ways we can think of it as a particle
of zero mass always moving at well,
the speed of light And it is for this theory, not for special
or general relativity, that Einstein was awarded
his Nobel Prize Because this concept,
which we now call the photon solved a number
of lingering issues with how light interacted
with the world But the photon brings us right back to the problem
of Thomas Young’s double-slit experiment Because if light has
both the properties of a wave and a particle What happens if you fire
those particles through the slits one at a time? Well, here is where this becomes
the most astonishing and humble experiment ever devised Because if you shoot one photon at the slits
and detect where it hits on the other side You’ll find that it impacts some arbitrary point just the way
you think it should And if you fire
a second photon through, you’ll find that it too shows up at some
other arbitrary point on the other side But if you do this enough times, you’ll eventually see
the same interference pattern build up that we got back in
Thomas’s original experiments. That is madness each individual photon, which should
be completely independent of the rest shows up at some seemingly
random point on your wall And exactly where
they show up will be different each time
you run the experiments And! Knowing where the previous photon appeared in
no way allows you to predict where the next one
will show up yet when taken as a group it’s as if they’re affected
by how they Should interfere
with each other This feels impossible and yet it is experimental fact And the reason for this phenomenon
is one of the most hotly debated mysteries in physics Because the only way to conceptualize this is that each photon passes
through both slits as a wave, interferes with itself and then resolves down to a photon
when it actually hits the wall What is going on here? What is this? No, no, no, this is magic. This is magic ! [sine wave] [meow] No, you’re right Zoe. I should calm down because
we are not done yet because here is where it gets really freaky Remember how when Thomas
was first doing his experiment? We said that if light
were really a particle we should just see two columns
of light on the other side of his double slit paper? Well, if you put a detector on the slits, so that you can determine which slit
the photon you fired passes through That is exactly what you get. That’s all you have to do You don’t have to change the experiment
in any way or interfere directly with the photon You simply have to measure
which slit the photon passes through. Why does it do this? Because a photon is a particle and a wave but it can’t be both simultaneously The mere act of measuring
which path the photon took Forces it to resolve the wave-like nature
of the photon into a particle And this may be the hardest thing to wrap
your head around in all of quantum physics because the most common
way to view this is that the photon
when acting like a wave isn’t a real wave at all but rather a wave
of possibilities That wave represents
where the photon could be but not
where it is It’s only when something acts
to detect the photon whether it be
your measuring device or the wall on the opposite side of your double slit experiment That the photon is forced to, for lack of a better term, decide on where it will actually be and in doing so becomes a particle More unsettling still, is the fact that
these waves of possibility interfere with each other
just like normal waves The interference pattern
we see from firing particles one at a time through the double slit experiment is caused by peaks
and troughs of possibility cancelling each other out When you fire that photon and the wave
of possibility hits your double slit paper It is funneled through
as two possibility waves Just in the way that any regular physical wave
would be and just like
those regular waves waves of possibility interfere with each other Essentially making it so there are places where it is
more or less likely for a photon to land when detected Thus when you fire a lot of photons one at a time through
your double slit experiment The bands you see are simply
the high probability lines playing out But if you think
we’re done getting weird, think again, we’re only on episode one so join us next time as we get serious about
this idea that energy only comes in discrete packets and begin our journey
on what this means for the future
of quantum computing. We’ll see you next time or will we just perceive you next time because
would that mean we’d have to watch you watching us to know the oh boy [outro song]

Daniel Ostrander

Related Posts

100 thoughts on “Quantum Computing – The Foundation of Everything – Extra History – #1

  1. Extra Credits says:

    Promised/hinted at in our Non-Euclidean Geometry series, we'll be airing this special sponsored series on Quantum Computing for the next six weeks alongside our regularly scheduled Extra History programming!
    You can get early access to these videos a few days before each one comes out, on https://www.patreon.com/ExtraCredits

  2. Matan Kribus says:

    this actually makes perfect sense… if the thing hit a thing. there will be a force that will send it back… so it dosnt "decide" its position.. its just gets stoped. cause it hit the thing…

  3. Danny B says:

    This probability wave b.s just seems like laziness. We cant figure it out so we come up with mystical voodoo to explain it

  4. matt winward says:

    2:58 Ahh, Kawaii, one of the fundamental forces of the universe.

  5. Nathan Huisman says:

    particle wave propagation time!

  6. Shawn Wilson says:

    I see you

  7. Eugen Barbula says:

    Noone teaches at university this sensation driven, double slit experiment, there are so much other possible explanations, for example, google for diffuse reflektion for light.

  8. Physicron S says:


  9. Nihaal says:

    Um..this tiny brain of A 8th grader doesn't understand anything

  10. Dan says:

    I just tried the Young's double split experiment and I can confirm that I can see the interference pattern shaped as the word "updog" in the font Arial on my wall every time I do it.

  11. welshpete12 says:

    It's all those flat earthers fault ! I it wasn't for them . We would be quite happily going on in our old ways , going round and round in circles !

  12. ٍِAshraf Kamel says:

    my salute to the Graphics team
    they made my giggle a lot
    great job everyone

  13. tvdetectivefan says:

    Had to find where updog came from and here is what I found as to the origin. A man goes in for a regular medical checkup, and the doctor tells him, "It looks like you've got a bad case of Updoc." The patient says, "What's Updoc?" And the doctor says "Nothing much—what's up with you?" – Sven Yargs

  14. Chantelle's Drawings says:

    0:49 i thought he said life for a second there lol

  15. Nikki M says:

    i didn't think it was simply us observing which slit but rather the act of measuring changes what's happening. It's not that our awareness has an affect but rather our measurements do. This made me feel as if the photons decided to act different because it like knew it was being watched lol.

  16. WizKidGamer99 says:

    Whatever that music at the end is I need it

  17. Jamie Marshall says:

    To the best of my knowledge observing the light that passes through slits to alter its outcome is a "thought experiment". That is, it has never actually been accomplished.

  18. Rex Longfellow says:

    When people say Infinity War is the most ambitious crossover of all time…

  19. Travis Pluid says:

    …So, what is the medium of possibility? You have possibility waves, but what the heck is the medium that possibility travels through?

  20. MrSaemichlaus says:

    I love how rhetorical expressions are depicted literally, like Einstein running with Planck's idea!!

  21. Ruslan Melentiev says:

    3:32 – Einstein did not recive Nobel Prize for Theory of Relativiness.

  22. David Burns says:

    When I was young I believed in scientists faithfully. Some scientists have betrayed that trust so my faith is no longer blind. Is the particle/wave thing actually true? Or is this just the theory that someone came up with to make it all work? Just like I'm not blindly accepting dark matter/energy, I'm not biting this stuff either until it can be proved incontrovertibly.

  23. Brian Meyrick says:

    6:06 how the stuff do you measure where the photon is without giving yourself away and hence changing the photon's reality? Are you invisible, non momentous? God Like? Include your own actions in the physics. What is troubling is that you are propounding ideas of the collapse of the wave equation as if it is known and proven fact .. it is not .. it is just an interpretation that convinces first year students. Expose the quandaries but don't insist on a view else this will all disintegrate into the nonsense of string theory. ( oops shouldna said that 🙂 )

  24. Francisco P says:

    whaat thats bonkers

  25. Facepalm Jesus says:

    hahaahahhahaahhahahahahahahahahahahahahahahaha 5:15


  26. Matthew Harris-Levesque says:

    Well… Does knowing I will be watching you work? Took a break soon after the voice change. Whether I'm over the switch or you've gotten better, something has changed – in me or in you – and I'm an "Extra" fan again after this one.

  27. James Diaz says:

    I miss the other voice

  28. Victor Ross says:

    The double slit experiment is revealing how the universe actually works. Versus how we perceive things. The best description I've read is that it's a bit like a needle on a 'record' in which each groove is a parallel reality. Some are more probable than others. We don't perceive the mechanics of 'jumping' from reality to reality, but it's happening all the time in real-time. Perfectly seamless and transparent (until you run tests like this one).

  29. Samuel Kerby says:

    How does this work with the Higs boson then I'm so confused and never been more intrigued

  30. Bryce Knape says:

    Is "updog" relevant somehow? I don't get it. The pattern resembles these letters?

  31. Stijn Engels says:

    Came here from the non-euclidean geometry, which I thought to be insanely well done, this in comparison is quite sad

  32. Ratchet4647 says:

    This sounds like what happens with electron orbitals around atoms and how they interact.
    Cool! This helped conceptualize better what I had previously only more loosely understood.

  33. Nicolas Reali says:

    can we appreciate how FUCKING ADORABLE that photon is

  34. Ian McLaughlin says:

    Does the fact that an object moving at the speed of light perceives no time have something to do with this? I only say this because just like the wave/partical shift, the speed change only happens when the photon hits something or is measured.

  35. Jog Chaber says:

    I laughed so hard at the part where Planck was super desperate…the board drawings cracked me up so badly

  36. MagnaCarterBCE says:

    Its ironic how the more I learn about physics, the more I consider the possibility that we live in a video game

  37. Joseph Hall says:

    I think the term “wave of possibility” is a great tool for underwing and remembering this concept

  38. youtoober2013 says:

    5:26 LMFAO

  39. youtoober2013 says:

    Alright… WHAT is updog?

  40. Flipping Science says:

    6:55 the trigger is backwards…….

  41. GDI says:

    It really irks me that none of your animation talent was put to good use here. You could have actually shown an interference pattern

  42. Toby N. says:

    Wait, what's updog?

  43. Magic_Zach says:

    Excuse me, what?

  44. Chris K says:

    Sorry guys but the animator should have sat down with a physicist while doing sketches, some of this is could really make people misunderstand this experiment.. Towards the end it makes the common mistake of misunderstanding the uncertainty principal as being to do with conscious observation. This would make consciousness something which affects the way particles behave; absurd. It is to do strictly with no physical process being able to be different based on a particle’s exact position and velocity. That process could be an ape shining light, or light shining off the sun; either ray of light has been hit or not, that will affect the particle’s position and velocity

  45. Magic_Zach says:

    Your artist had no clue what to draw, and just made this a lot worse and more difficult to try to understand.

  46. HwaJeong Jeon says:

    I don't know how to sort this video, it is Scifi or history.

  47. Francesco Rizzo says:

    uuuh this "conscious observer" thing… watch this video and you will know by Neil Degrasse Tyson – https://www.youtube.com/watch?v=5XP-DQW_1gI&t=34s

  48. Shiloh Schwartz says:

    What's updog?

  49. roguedogx says:

    5:33 you seem to be taking this really well.

  50. Rafael David says:

    3:00 .When I'm bored, I doodle it on a notebook.

  51. moonymonster says:

    Raise your hand if you replayed this 3 times and still are baffled. Wtf physics you really are magic

  52. sebatian says:

    GOD is REAL

  53. Guhun Son says:

    You DO intefere with the photon. You would never be able to measure it otherwise…

  54. doifhg says:

    Pizza scale

  55. kvtassel says:


  56. paperchasin23 says:

    I’ve heard this described a million different ways and this is really unique and more digestible. Good work.

  57. Parth Pratim says:

    I DON"T like the pronunciation of this narrator. I liked the narrator of the Euclidean Geometry a billion times more. Everything was clear.

  58. travis taafua says:

    My brain hurts

  59. Limmeh says:

    UPDOG (Ultimate Paralyzation of Damaged Organ Genetics) is a process in the BOFA (Body Oscillation / Fatal Area) in which DNA is modified into having LIGMA symptoms in the genetics. This is only a stage 1 on the BOFA power level, however a person will suffer from intense addiction to Fortnite, get free Xbox Live or PlayStation Plus, and the ability to gain a free copy of the Save The World mode at birth. Though most of these symptoms sound positive, one negative symptoms will occur, a UPDOG victim will forever stay a virgin. It is unable to change that fact. Some popular examples of people with UPDOG include: TSM_Myth, every 12 year old, Ninja, Runescape players, and most likely you.

    Or it could be a simple joke derived from "What's up, dog?"

  60. mike says:

    Our universe is a fixed system until some laws are bent ! I believe lightspeed can be overtaken by using subspace to traverse vast distances

  61. Junebug482 says:

    What is updog?

  62. Matthew Newman says:

    please bring back the original narrator.

  63. Wintermute01001 says:


  64. G11 P08 says:

    this is more confusing than the kingdom hearts timeline!

  65. DJ Wise Pariah says:

    … What if light in neither a wave OR particle, and is instead the actual aether everyone was looking for all along?

  66. Abner B says:

    Really wished they showed the interference pattern and particle pattern instead of showing "updog" whatever that is.

  67. Pepsi Doggo says:


  68. Spencer Abdo says:

    Well, I learned a few things from this. Not least of which the sound made when my brain melts through my shoes.

  69. Doctor Doom says:

    Why use Updog to represent interference pattern when you could have actually just use the actual interference pattern. This will confuse a lot of people.

  70. Amir Hagit Einav says:

    Mah boi Einstein saved us all

  71. RayMKlll says:


  72. Kamille Willets says:

    Ok I actually love that as they explain this, they are also going through the mental "wait, what?! That doesn't work! WHAT IS THIS MADNESS!!!"


    But don't waves need a medium to travel?

  74. Dax Robinson says:

    whats a cactus

  75. Wedgie Man says:


  76. Dave Hoffman says:

    Those photons are so cute.

  77. Samuel Schönenberger says:

    I watched this the last time before I learnt it in Physics so now I'm rewatching it

  78. Worrystone AJ says:

    the whole shebang

  79. Brady Menting says:

    the question at the foundation of everything: WHERE IS WALDO

  80. Frail Comic says:


  81. Cody Greenland says:

    Oh so like superpositions

  82. Steven Whitfield says:

    I really don't like this host at all!

  83. Micah van Oordt says:

    Wait wats updog

  84. UnDeaDCyBorg says:

    I actually had to go to the comments and see people complain about "updog" to understand that was meant to be a joke or smth.

  85. Fathen says:

    What's updog

  86. Thảo Vũ says:

    Hey! It's this Extra history or Extra Sci Fi

  87. ThatGuy Man says:

    4:24 what if the photons are like drops of water… when it hits a surface it splashes and spreads out. It doesn’t remain as a uniform droplet. So in some areas it would remain thin (interference), but if another droplet landed close to each other they tend to stick together and form more water (amplify)

  88. ThatGuy Man says:

    What if the waves of light are interfering with each other on the way from the wall to the observers eyes or measuring instrument so it would just appear to be an interference patter

  89. LACHIE D says:

    You got spicy science in my history…

  90. epiclolyay says:

    Lol this isn’t history

  91. Dominik Lehn says:

    So… You can tell by the way certainly… Things react if they have been observed… Does that mean,that if we say,observe something like that without "catching" it,some other civilization could potentially learn of our existence just because we looked at something?

  92. Lenneko98 says:

    I feel like I do and dont understand this all at the sametime… my head hurts.

  93. Chris Main says:

    So, what you're telling me is that light is homoiousian?

  94. Rodolfo Soto says:

    damn I'm disappointed this channel is great when it refrains itself from science, even worse you decided to start with quantum physics, next time try something simpler.

  95. EL GUSTO The bad artist says:

    whats updog

  96. Jackson G says:

    take away from this, plasma guns good, use them in your tabletop

    regardless of that we enter into a higher level of thinking in terms of debating they possible

  97. Nonsense With Jessie says:


Leave a Reply

Your email address will not be published. Required fields are marked *