Where Are The Worlds In Many Worlds?
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Many Worlds interpretation of quantum mechanics proposes that every time a quantum event gets decided, the universe splits so that every possible outcome really does occur. But where exactly are those worlds, and can we ever see them?
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Hosted by Matt O'Dowd
Written by Matt O'Dowd
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Directed by Andrew Kornhaber
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Stop performing these double slit experiments. We’re running out of space to store these universes.
Step 1: Set up a quantum experiment station (ie measuring the spin of a quark, double slit experiment, etc)
Step 2: Predefine the results to a certain action that you will do (ie if the quark spins up then you will buy a random person a coffee, if the quark spins down then you will call your mother)
Step 3: Do this several times a day to create as many alternate timelines as possible
Step 4: Profit
@@zacharyschafer9493 🤣🤣🤣🤣
We must protect the sacred timeline
they exist in a hilbert space which is a domain of n dimensions-that is infinite dimensions, but still in our very same physical space. the worlds can be thought of as being out of phase with ours.
just look inside the black hole from that episode about black holes
Damn, I ended up in the universe where this doesn’t make any sense
Take 5 steps back, step up step down put your right foot out, put your right foot in. Grab your brain and shake it all about - you're doing the modern physics.
You wouldn't end up in one universe in this sense. You would end up in a path or branch of universes. (If you define universe as everything included in your reality.)
@@user-gd5tr7gw7s luckily I only have a borderline attachment to reality! lol!
Find solace in the fact out there in the multiverse, they're be a version of you who actually discovers and explains this instead of not get it.
Lolol same
"At the risk of getting technical..." that's a big point of this channel! Don't hold back! :)
That rocket has launched, suffered catastrophic malfunction, and passed the event horizon of a black hole years ago.
It’s mindblowing
@@Yora21 lmao, i like it :)
well there's a certain portion of "marketing" that is being done, because he promises the thing to be explained in more detail in the future. if it's enough detail to cover a 10 min vid, it's more revenue, and better productions
I have a nephew called Matthew Anderson but, as you can see, he has an extra 't' in his name.
Perhaps I've made contact with another branch of the multi world.
How much of the viewership of this channel have absolutely no idea what he's talking about every time, but just listen anyway? Just curious.
I try, but a lot of the stuff is too much for me.
Even as someone with a good education and enormous passion for physics, this channel makes me feel like a neanderthal.
I take solace that, individually, I understand the words... Mostly...
Probably most of us don't understand and that's ok
I kind of keep loosing and regaining traktion.
I have a master in quantum physics, and I can understand most of the things he is saying by I need to focus. I think, anyone without several years of studying quantum physics cannot unferstand, but only grasp a vague idea.
“Ahh yes, quantum” I nod at the screen like I actually understand any of this while stuffing Doritos into my mouth.
Nobody does understand this. And if they claim they do, they subscribe to the "shut up and calculate" interpretation.
"Like, quantum, dude." Milano cookies. Same.
...ah! I was thinking the same but sipping tea! ☕
“Do you just put the word "quantum" in front of everything?” -Scott Lane.
Nobody on this planet truly understand quantum physics
I love that many topics like the double slit experiment are briefly explained again, to build refreshers for non-physicists like me. This helps me still get the most out of the video- thank you for the great content
Speaking of "splitting quantum spacetime", there is an interesting consequence of this:
We know there is no general way to say which two points are "the same event" in two different spacetime manifolds, and since this measurement would cause you to do something differently, that means the spacetime would warp differently in the two different branches as well. Which means the spacetime manifolds would have to be in superposition as well as decohered, and you can't really match up where you are in this branch with a location in the other precisely.
I love that this channel covers alternate quantum interpretations with more technical vigour than the average CZcams science video
the ripples on the pond have no affect on each other was a very useful analogy for me to properly understand this.
definitely looking forward to the video on how we could communicate with the other worlds, that sounds interesting.
We´ll probably need something like an Ansible for that.
Hopefully we'll be in a world where he posts that video. In some other worlds the video would never be posted.
Just give them internet access or just call them...
@@nahCmeR how to
Probably has something to do with making a "phone" whose entropy doesnt increase idk though
This hits different after that Loki ending
Don't it, though?
Yes
Beat me to it!
just saw it. Mindblown.
I wonder if they did this episode after the finale on purpose, or if it's just coincedense.
I actually thought the whole universe splits at every wiggle. Recombination makes this far more confusing and even more interesting. It also makes me wonder if there could be something like a partial, local, or pocket-like split, where a split is still attached to or recombines with its origin.
Im having a hard time grasping how out-of-phase wavefunctions could recombine, isn't a quantum-state also bound to the fact that it is/isn't collapsed? Therefore it could not get into an intangeled state anymore and would be out of phase forever, no matter if the remaining wavefunction is identical.
Could probably be an explanation for the Mandela effect and other weird, well documented “supernatural” phenomena.
Great video. PBS Space Time, Isaac Arthur, John Godier, and The Exoplanets Channel are definitely my favourite channels!!
Hossenfelder trumps all! Kudos, though, for mentioning the implausibly named Isaac Arthur.
Anton too. Don't forget Anton. Man's got entire scientific journals uploaded directly to his brain haha.
@@helicocktor I have a feeling we're all subscribed to the same channels
I agree. They are all excellent channels. Check out ScienceClic English. It is truly fabulous.
@@lasgio_ haha yeah. It's scary how effective youtube's algorithm is.
This stuff normally breaks my brain, but you explain it so well! I liked the ripples analogy a lot.
ripples on the pond is useful for understanding why the many worlds dont interact with each other.
In another universe, or world, you still do t know that…
Your brain actually broke up into countless decohered versions of itself
If you think you understand quantum mechanics, then you do not understand quantum mechanics...
I think PBS Spacetime may be my favorite educational media on youtube, for both being informative and in depth but also often tackling topics just on the horizon of my current understanding. Not something I've seen before, but not something I don't already have the foundation to understand. Really often I'll be wondering about something and there'll be a spacetime video about it within a month or two.
I just hope my other variants understand this episode better.
And all the other versions of this episode
Please, more about the recombining of wave functions?
Oh, the times I've said that.
Have you watched the videos on decoherence? You're looking for "how decoherence splits the quantum multiverse", "how do quantum states manifest in the classical world", and I think "how the quantum eraser rewrites the past" could be relevant too.
@@DrVictorVasconcelos Thanks for those pointers! It's tough to keep up with the backgrounders and followups on this channel when you only discovered it recently, and don't have time to rewatch everything from the beginning.
I love how I paused the video to write a comment about how it is now always possible to recover initial waveforms, and then right after I unpause the video Matt explains how it is not always possible to recover initial waveforms in non-linear systems. I love this channel! :D
I love recommending scientific Recommendations. Want some?
Wow, that was a great explanation! A pond analogy somehow feels much better to me than a branching tree. I'm not sure if I'm a fan of the many worlds interpretation, but I think after watching this video I understand it better (obviously on my very shallow, amateur level). Thank you!
I feel like a variant of Matt is going to end up being the rl Kang the conqueror
I'm loving how I watched that and then the CZcams algorithm popped this.
I think we all have our variants in this situation. Just donno if all of them are good as me or better
Matt the conqueror
@Ke Ge Nathaniel Richards is from the 30th century, that's not even 1000 years from now.
In my other position wave function and phase relation measurement, I actually understand this.
Maybe not. Many worlds might mean that all possible things exist somewhere but that doesn't allow for the impossible. If you are actually incapable of understanding this, no other yous that do understand it will exist.
@@wingracer1614 That's not true. In other worlds there may be genius versions of Peter.
@@alwaysdisputin9930 Then one must ask at one point is he still Peter?
It's hard to explain, but I believe I have a very interesting theory. I believe that quantum events only occur due to previous quantum events. This means that maybe our world is only possible due to the entire history of quantum events choosing the exact right path. This means that today's quantum events don't 'split' into all possibilities and the first quantum event from the beginning of the universe is the only event with the ability to split. For example, if I tell Joe a secret, someone who doesn't know about the secret can't say oh I wish they never told Joe that secret (quantum events are impossible to occur from a history where they cannot occur), and the only original secret holder who had the possibility to tell someone (or anyone - all possibilities wavefunction) could make that decision. And if the secret holder doesn't tell anyone, then that reality never occurs (possible explanation why there is only a universe that functions with maths). So it's basically the many-worlds interpretation only works at what we know as the 'big bang'. I feel like this is kind of a bad explanation but it's so hard to put it into words.
@Nad Senoj but that was what I was claiming? That there could only be the initial quantum event that has the ability to encounter all possibilities. And I mean im completely open to that initial event happening more than once. Maybe an infinite loop of big bangs (quantum event starter)
You can only see worlds that you're a part of...remember that kids
Quantum immortality!
Come with me and you'll be in a world of pure imagination.
yeah it's split into left and right lol.. ;)
"the entire world doesn't split with every atomic wiggle", only due to interactions.
Q: does wiggle refer to virtual particles popping in and out of existence? What is the shortest distance (volume) that could include an interaction?
Apparent quasi Planck Volume based upon a value of the linear Planck length
No. Virtual particles are a math trick. They don't "pop" into existence because they aren't real. That's what "virtual" means, not real.
This is especially true in many worlds, in which the wave function and field values are always continuous over time and space. The term "splitting" is really deceptive; it's better described as partitioning. There are no "new" worlds being generated starting at an event of some kind. The wave function is partitioned when there is no phase coherence between superpositions. All of the "worlds" live in the same wave function.
Yeah this video just showed PBS spacetime producers do not truly understand the Everett interpretation or at least the version most everettians accept. "The entire world doesn't split with every atomic wiggle, only due to interactions." This is wrong for multiple reasons.
1) The "world" (or a much more suitable word "timeline") that we experience is not the entire universe and interactions within the individual branches mean nothing for the actual entire universe. Everett interpretation holds that there is only ONE universe and that our timeline is just an infinitesimally small slice of it. What the universe actually is, is one giant wavefunction where every single actually possible state is contained (one colossal schrodinger's cat), so we aren't seeing the entire universe nor do interactions within our branch change anything. The universal wave function progresses deterministically in accordance to the Schrodinger equation no matter what so yes, every single moment every possible path for every particle to take is already contained within the progression of the universal wave function. "Interactions" or "observations" in themselves are meaningless as the universal wave function progresses the same regardless of the events which happen in the branches themselves.
2A) True everettians know there is no actual "splitting," and a "split/branching" of timelines is only talking about an illusion on our end. So though to our slice of timeline perspectives the progression of the universal wave function would seem like "splitting" that is not what is actually happening. But every possible future outcome is already contained within the universal wave function so yes, for every moment in our timeline there are an infinite number of futures (in our perspective) that will stem from that moment but that is because of the progression of the universal wave function, not interactions within individual timelines that are somehow believed to cause splitting. To the universal wave function there is only 1 future outcome, which is why many timelines is a deterministic interpretation yet indeterminate at our level.
2B) This may be controversial because it is easy to take out of context but the Many Timelines interpretation implies that "interactions which split the worlds (except not really)" are more due to information distinguishing us from otherwise identical other timeline versions of ourselves. The double slit experiment is one of the few times this becomes noticeable. Consider for example the delayed choice modification of the double slit experiment. They have the same double slit set up but this time they have crystals to split the photon into an entangled pair in which one member of the pair goes to the back wall and the other to one of the detectors A (if it came from slit a), B (if it came from slit b) or sometimes a "which path information eraser' which could come from either slit detector C. All the detectors are placed AFTER the backwall so the member of the pair going to the back wall will hit it first and the member going to one of the detectors after. But even when the detector is in such a place such that it would come after the member of the entangled pair that hit the backwall the interference pattern is gone if whichpath info is received either through the other pair which detector a or b. But the interference pattern is still up if it is detector c which could've came from either of the slits. Other interpretations other than Everett/manytimelines have to assert that some retrocausal mechanism is happening here...where somehow because the photon was detected the which path information was retroactively sent backwards in time and caused wave function collapse, a mechanism which is not actually possible or in accordance to any understanding of physics we have. In fact if such retrocausality were possible we'd never expect to see interference at all regardless, since there would be no reason for other outcomes or possibilities to ever exist and interfere if there was only 1 outcome that happens and thus only one that would be able to retroactively send information back in time. This is why the transactional interpretation is ruled out as well as any wave function collapse interpretation. The mechanism for seeing interference or having wave functions at all in the first place becomes impossible if retrocausality is actually at work. The more likely notion about what is happening with the double slit experiment is that the information from the detectors made us and the rest of the outside environment distinguishable from other sets of versions of ourselves that had other photon paths taken with other detectors hit. The mere fact detector a or b was hit would be information that made us and the rest of the environment outside of the system significantly different from other timeline versions of events as opposed to if there was no detection where none of it would matter. Without detection none of that information about the system of the experiment matters to us, multiple outcomes can be true and it doesn't matter, so we see interference because it as if multiple possibilities were happening at the same time without those possibilities mattering to us. But Many Timelines is the only logical way to explain the double slit experiment and it's delayed choice erasure modification.
But TL;DR is the Everett interpretation is incorrectly represented in this video and there is no actual splitting.
@@hyperduality2838 Err. Okay so your name is "Hyperduality". Do you perchance go around CZcams comment sections always posting similar lists of examples of duality?
I'm not sure what amazing realisation about the root of reality you think you've struck upon here, but I'd assert that maybe the reason duality crops up a lot is because "a = b" is attractive to people because they find it catchy and elegant and easy to understand. So theories which have a simple "a = b" sound bite to them tend to be remembered more by the masses.
@@litafbobpompeani7711 boom. Better than my explanation. 10/10
12:20 *CONQUERING INTENSIFIES*
"At the risk of getting too technical,"
-Dr. Matt O'Dowd, summarizing PBS Space Time
(edit: to clarify i still love pbs space time in all its technical jargony goodness)
You should see the math for this....
@dafuqawew Correct. I wish PBS would copy eg DrBecky or DrPhysicsA so we had the epic topics + clear explanation
Tbh I can’t really imagine there being any world where I would pick salad over pizza.
You were trying to impress the love of your life who you happened to be next to when ordering food in that other world.
I would gladly pick homemade salad over gas station pizza.
"☝️ Presenting to the emergency room" is a phrase I wouldn't want to be associated with my obituary.
I cut my pizza into bite size chunks. I chiffonade some basil and toss those two in a bowl with some Parmesan (sometimes blue) cheese and hidden valley ranch.
Pizza salad. Welcome to the future.
@@silverybound no one wants to be the subject of a chubbyemu video 👻
@@addammadd
"Isn't everything you eat bite-size?"
Mitch Hedburg
11:57 I'm thrilled that you mentioned recombination. Almost no other sources ever mention it.
I love recommending scientific Recommendations. Want some?
My brain has just split into two migraines. This is heady stuff
At risk of sounding oblivious, where is that guy who always acts as the quantum observer from? Those visuals are hilarious.
He disappeared, going backwards in time before the BIG BANG.
Did you know that Argentina has a quantum economy? The value of the dollar is in superposition of different values, we even have a name for each one of them.
Explain.
Schrödinger dollar.
That's a good one
@@Smerpyderp gvmt regulates how many dollars you can buy according to how much you make, obviously there are parallel markets with different prices
If were being serious, yes I knew Argentina has its money all effed up, in a big way infact. Here's the real ask though just because a big Mack is 68 dollars and a gram of uncut Cociane is 4. 86 does that really mean the dollar performs as both a point and a wave?
It had never occurred to me that the many-worlds interpretation would be so efficient with regards to space.
This has to be one of the only clear video about the many world interpretation. Thanks and congrats
It's interesting to me to imagine a universe where every double slit experiment gives results that don't show a wave nature of particles because of dumb luck, so scientists have a worse understanding of quantum mechanics.
This feels like a sitcom writing prompt. I love it.
The question is which experiment in our world is the one that always fails?
hmmm I wonder if our universe is also having some continuous dumb luck in some observations... we would never know lmao...
You are perverse my friend, and like it.
that has to be an extraordinary amount of dumb luck
In one of the many worlds dice always roll the number I predicted beforehand. This seems to suggest that in some worlds magic appears to be real.
in theory this is true. in some many worlds the particles that make me up happen to fly apart while at the exact same time somwhere else random particles reform a perfect "copy" of me. i then claim i am a wizard for the rest of my life.
@@goldenbananas1389 you wouldn't be able to fly, that would break laws of physics, however, it's entirely possible for there to be a world in which you dream of everything that will happen on the next day without fail
@@jvcscasio I never said there is a world I fly. Just a world we all the particles making up my body move apart and I basically disintegrate. But somewhere else in the universe a bunch of different particle randomly form into a perfect copy of me.
And also in the same way a particles position can be in a super position it’s velocity also can. Meaning in theory the velocities of all the particles making my body up randomly align upwards and pull me up before I quickly come crashing back down. The chance of this happening is too small to consider it but in the many worlds interpretation it happened somewhere.
It also means there is a world where every coin flip, ever, landed on heads
@@Sigma00000 yes
I used to sit in my childhood barber shop opposite of the big mirror behind those chairs. Another large mirror was across from the first, and by positioning myself in a certain fashion, a gallery which had no end appeared in the reflection. A snaking corridor of exact images curved into infinity. Lining up the reflections seemed to reveal dimensions unending and bending out of sight.
I thought of each one as it's own reality. That any one of them could be entered and reacted with, even destroying the entire space, but not affecting any other.
A multitude of parallel dimensions running to eternity.
My theory is that we don’t only have infinetly many futures, we have infinetly many pasts too. The many worlds go both ways and there is no loss in coherence, there is just a transfer of coherence between worlds, coherence might actually be a preserved value like spin, charge and information in general.
The universe's git log must be crazy, but I'm pretty sure I'm in a 'detached HEAD' state.
CS gang represent 🙌
what if God created all of it in one commit? After all, He is God.
The universe is forgetting to do frequent merges it seems.
The theory of many feature branches
Bruh :)
It's cool that Matt wrote his words. Truly an intelligent person.
?
@@porple4430 What do you need explaining?
I think he considers this as a live talk, respect 👌. He edits only a few rare occasions... Applause ✌️✌️✌️
@@koushikkashyap439 I don't get it. Are you saying Matt doesn't write his material and use teleprompter when recording?
I was lost 5 seconds in but in another world I understood it completely
Honesty!
I love the TTC subway Easter egg! Cheers from Toronto!
This episode coming a day before the season final of Loki, and talking about the same subject? Coincidence? I don't think so, I am mounting in suspicion about Dr. Matt O'Dowd being the man at the end of time, ruling the sacred time line
Sounds like Chronotrigger.
@@Thomas.Wright Chrono Trigger/Cross, mixed with the end of Final Fantasy 8.🙂
@@masamune2984 That castle had major Ultimecia vibes.
Such a good episode
Thought the same thing
Could you do a crossover episode with the "many worlds interpretation" and the "time reversal property of the shrodinger equation"? Multiple futures is cool, multiple pasts is cool too.
He actually did that video. Just in a different reality.
@@Robert_McGarry_Poems well played my friend
I would love to see that episode in this reality too
@@skandragon586 there's a reality where this is that video and you commented you'd rather not see that episode in this reality
@@freedomachine2185 and there is a reality where i never replied to your comment coz u never commented but look which reality we ve chosen
I’ve listened to you talk about collapsing the wave function for years, but didn’t understand what it meant until this video - thank you
I still don't, but hope collapses last.
Neat analysis! Thanks for uploading!
Let's be honest Matt, we always pick Pizza.
Lol I also thought of Pizza maybe we're entangled now 🍕💭
A54a55a5aaaa55a#aaa5a55aaa5aa6555aaa5sasassa⁵54a4⁴
5a5555sss555ss5555a5saaas#5ss#5a555545aa
We're well in to the pizza-centric branch of the Many Worlds 🍕🌎🌏🌍
there can be infinite amount of branches of reality... there is absolute ZERO chances that I will pick salad over pizza.
Well quantum mechanics says there are infinite other universes where you indeed did pick salad over pizza.
@@beyondthelife6750 no, it says that if the chance is positive, there are infinite universes where it happens, if the chance is zero, there are none
@@gabrielgrabois you need to re watch and understand the video and not just that, do some extra research on this topic. If it is true which I am not saying it is but highly possible than in all honesty it actually cannot happen an infinite. Maybe millions or billions but not infinite. Infinite is not a number its a concept it means forever with no end. Hate when scientists use it with no basis sometimes. However our universe or other universes can be truly infinite. Just no true infinite in the quantum realms.
@@beyondthelife6750 / @gabrielgrabois Even infinity would not need to include every possibility. (Every possibility may be less than infinity, too.) Natural numbers in mathematics are infinit, but do not include all possible numbers. Maths with infinities is very different und sometimes surprising. Though I donnot believe in the Many World Theory. Which is also not science but believe. I prefer to believe in "decision" at the moment of interaction.
If realities truly are literally infinite, at least 1 of those realities contains a version of you that is a vegan or vegetarian health nut.
Thank you! 💖 I was wondering about this topic. I look forward to hearing if it's possible to contact the other "worlds"
Sir you are awesome. I like the way you explain,collect,and display the information. I understand the concepts very easily. We want you sir. We love you sir
Trust me, all infinite versions of me picked the pizza
Idk man, is there bacon in the salad?
pineapple on pizza o.O
Except for the version of you that is lactose intolerant
You may have just invented some sort of quantum heredity.
"There's nothing any of him could do. Just something about pizza always collapsed his wave function."
@@0130wallace this is first thing i see and click in the morning, and allready tears on my eyes, happy tiers - Bob Ross
One thing I've not yet understood in the Many Worlds theory is how the probability amplitude fits in. If (simplistically) every possible outcome results in a new world branch, then does the probability amplitude have any meaning?
Made perfect sense. Thank you
I like it, especially the last bits explaining how the probabilities can recombine and you are not getting endless ‘real’ duplicate universes…makes sense. There is a way of looking at this in a less Quantised model. If each physical dimension (direction) represents a way the lower sets can be different, then by Dimension 4 (time) we see every way the three spatial ones can be different and by Dimension 5…we have a probability field giving the alternative versions of the lower 4. In the fifth (non physical) Dimension every possible path exists, but some being more likely than others, because each branch forward had a probability of occurring. The nexus where they all meet is ‘now’ and the trail left behind is the single resolved happening of history. Looking forward the least likely paths are disparately flailing off each side of the model and the few most likely align with a central fuzzy core of probabilities. Think of this as being orthogonal to time.
Nice bullshit. ;-)
What a wonderful explanation of such a complex concept. I expect that I will never fully grasp quantum physics but I am certain that it is the single best explanation of partial interaction at the smallest of scales we currently have.
I love recommending scientific Recommendations. Want some?
so if all decohered branches of the wave function do still occupy the same spacetime, just out of phase with each other, could all that additional invisible (to our decoherence) quantum mass, or at least the branches that are more closely aligned with our own, be the source of all the additional gravity we observe as dark matter? and if they're infinitely branching off and expanding the overall harmonic sequences of the wave function, could the wave function literally be stretching out spacetime, and that's what we observe as dark energy?
Hmmm im not sure if that wouldn't lead very very fast to infinitiys. Ofc it would align in its core mechanic perfectly with the acceleration of spacetime, but if every slightly out of phase branch has a set mass-proportion influence on its parent-branch and vice versa, wouldn't that with (idk for sure) 10^500 events per second per cubic centimeter create just one gigantic, ultramassive gravitational anomalie? Not a black hole perse, since that would require dark matter to be barionic in nature, but if it's gravitational influence can be measured, in that circumstance it would get out of controll very fast I assume.
@@hitbox7422 I think it would be more like our universe is continuously losing mass compared to the incoherent background. Total mass is conserved, but our particular (coherent) branch of probability is becoming an increasingly small fraction of the total wave function. At the same time, a lot of our close neighboring branches will still have similar mass distributions, so much of that loss is not immediately obvious. A planet may have a lot of incoherent mirror planets, but none of those incoherent copies are changing their trajectory or losing much mass.
The Wolfram Physics project actually explains all this much more fundamentally and it's quite obvious. I recommend reading into it.
Thanks. I appreciate your efforts very much.
Imagine being in that one universe where all particles happen to have not decayed. All the posturanics and whatnot, I mean.
How borked would physicists be? Sure fusion happens all the time... but we have all this seemingly inert heavy element lying around that logic says should decay... but never has!
LMAOOO
Imagine being in the universe where your bones spontaneously became radioactive and gave you bone cancer. ☠️☢️☠️
Since past decay (or the lack thereof) has no bearing on future decay, then most of the universes where all particles happen to have not decayed will immediately start having particles decay (since that is still the most likely outcome for each moment in time). This would throw physicists into confusion and chaos. They would forever look for what caused this event, when the real answer is "coincidence".
Would physics and science even exist in those branches?
Imagine if the electron is meant to decay, but hasn't because of the universe we are in...
Every time the ripple intersects, dejavu intensifies.
You guys did it again! Great video.
This is an amazing production. I hope that they keep paying these guys.
they got pretty well paid patreon dont worry they're fine
Rooting for the world where my daughters don't have CF and can breathe free indefinitely. Let us know when physics helps us collapse reality onto that world, please. In the meantime, thanks for giving a dad's busy mind something else to think about for 15 minutes.
Matt, if you manage to come back from the other Many Worlds timeline, how differently has that timeline evolved compared to our timeline?
im gonna have to binge watch this channel
I had never understood the many worlds hypothesis quite like this, thanks! Previously I had thought "if there are infinitely many universes, then every combination of quantum probabilities can occur." But with a wave function, it's not that there are infinitely many universes, it's more like there is one "surface" that looks different depending on your phase...
Matt, how old do we believe our Milky Way galaxy to be and also the Andromeda? Also, if you go by the "Big Bang" theory, can you explain how after billions of years these two galaxies are on a path to collision if everything exploded out from a singular point? Thanks to you and the PBS team for all the great content.
Im glad you mentioned that the universe doesnt split every time a particle wiggles, but that raises the question - how often does the universe split? Can we somehow estimate it?
I would think something like manifestation. Consequence. Many . Hopefully all on good thoughts. Imagination is creation. Once thought or spoken out I'd think it's born created. Take it like said looking back at 10's of thousands,of hundreds of thousands. Jump to conclusions pad.
This channel always brings me more questions than answers and diminish my self-confidence as a self-learner.
The choice is yours. Educate yourself in real physics or take LSD and watch videos about alternate realities.
@@paulwolf3302 Or try to emulate Richard Feynman, fail and end up opening a bar in front of a Brazilian beach.
Oeh this was a good one! And well explained :D
Given that all the particles in the brain are connected one way or another (chemical bonds and so), wouldn't all of their wave functions be already collapsed according to the decoherence theory?
I have the same question 🙋♂️ did you get an answer?
@@richerite Well given that im doing a phd in neuroscience I hope to get an answer someday haha
Amusingly, you could also say that every known law of the universe is just due to a particular set of quantum coincidences, and our daily experiences are just due to dumb luck events.
The question that arises from that is whether it's possible for a quantum event to occur that changes the known laws of the universe and causes everything to just vanish.
Remember the Occam's Razor
You could say that since all ripples exist, and that it’s possible to exist, that we exist only in the worlds where it’s possible for us to exist. Therefore, since it’s possible for us to exist, we must be guaranteed to have exist, and there’s nothing that luck has to do about it
I wouldn't be so quick to call it random, quantum mechanics works, we just don't know why. I would argue it is a law of physics, and if it is repeatable it's not random right?
But if all these coincidences happen "somewhere" in the infinite universe then obviously we would exist in those parts where the laws allow our existence. In all those other parts with some different laws there is nobody there making comments on CZcams. Same as there is nobody there in the middle of a desert, on Pluto, or in the interstellar space, even though it's infinitely larger than our tiny biosphere. :) It's called self-selection bias..
Can’t wait for the next video. Can’t wait to send a message to myself in the other world and exchange notes about life!
What a great episode
In other descriptions of MWI I've never heard the idea that worlds are recombining, not just splitting. So, are there more worlds tomorrow than there were today, or about the same number?
I've always seen it this way... Imagine putting your socks on in a closed room, you randomly pick a first one (in a way comparable to the Schrödinger's cat thought experiment) then proceed to put on a second then leave the closed room. To outside (non)observers, there is a period of superposition of two states where you have just one sock on each foot (if you were to open the door early and look), then eventually you have a sock on both feet and it no longer matters what order it happened so the two 'worlds' converge again.
I’m always one sock short. I’m certain if we can find these other worlds, I can find my missing socks.
@@wadeworkman7283 you sure your real name isn't Ren?
tl;dr : I'm not sure that "the number of worlds that there are according to the MWI" is a meaningful question.
The dimension of the Hilbert space is unchanged. One can apply different projection operators to restrict to different subspaces, and view the overall state as a sum of the different parts you've split it into with the different projection operators.
But, there are different ways to split up a vector space into components.
Like, suppose you have the x,y plane , where like, you have points like (2,3) and (4,7) , and you can add the points together so that (2,3) + (4,7) = (2+4,3+7)=(6,10) .
Now, you can have a pair of projection operators, let's call them P and Q, where P(x,y) = (x,0) , and Q(x,y) = (0,y) .
You may notice that (e.g.) P(P(x,y)) = P(x,0)=(x,0) , applying P twice does the same thing as applying P once.
That's basically what P being a projection operator means.
Also, note that P(x,y) + Q(x,y) = (x,0) + (0,y) = (x,y) , the same thing as we started with. So, we could say P+Q = I (where I(x,y) = (x,y) ).
now, P might correspond to "in the case that the particle is spin up" and Q might correspond to "in the case that the particle is spin down".
On the other hand, we could also have another pair of projection operators, R and S,
where R(x,y) = ((x+y)/2 , (x+y)/2) and S(x,y) = ((x-y)/2 , (y-x)/2)
(If you don't know what I'm talking about in the following sentence, just ignore it and move on; don't worry about it : you could also write these as the 2x2 matrices where R has (1/2) in all 4 spots, while S has (1/2) on the main diagonal, and (-1/2) on the other 2 positions. )
To check that R and S really are projection operators, apply them to (x,y) twice and confirm that you get the same thing as if you applied them once. I.e. check that R(R(x,y)) = R(x,y) , and that S(S(x,y)) = S(x,y) .
R and S could correspond to "in the case that the particle is in the spin left" and "in the case that the particle is spin right" respectively.
Note that these two ways of splitting the x,y plane into two orthogonal directions, aren't, uh, the same. They are different and incompatible ways of splitting things up into 2 variables. two different ways to split the vector space into orthogonal subspaces.
Of course, when we are talking about the wavefunction for the whole world, or even just everything on earth, it would have many many more coordinates than just the 2 coordinates x and y. (for the universe as a whole, it should be infinitely many I think, and maybe infinitely many even for local stuff but maybe not, I'm not sure. It is often at least convenient to treat it as infinitely many.)
We can talk about projecting out parts of the wavefunction corresponding to different outcomes of some event, but there are also other ways it could be split up.
So, my understanding of MWI (which, I've not looked deeply into MWI in particular, just looking into the math of QM with some passing familiarity with MWI. "shut up and calculate" and all that. So, take this with a little bit of a grain of salt), is that, you can split up the universal wave function in many ways, and in some ways of splitting it up, different components will correspond to us having different observations,
but, at least until we assume that what we care about is "what we observe as humans", there's no singular "this is the right/standard/canonical way to split up the wavefunction into parts/'worlds' ". (though, see caveat [a])
So, I don't think the question of "how many worlds are there (under the MWI interpretation) and does this number increase or decrease?" has a meaningful answer.
I guess you could ask "what's the smallest number of orthogonal components you can split the wavefunction into such that, in each component, each person's observations and actions and thoughts and whatnot have a single well-defined value",
and I think that number would, probably be increasing? (??)
(and I guess you could call those "worlds". But I'm also not sure that that's an entirely well-defined question, because like, well, precisely defining what a "person" is in quantum mechanics, probably isn't really feasible, and maybe things don't split up 100% cleanly? I'm a bit confused here.)
I don't think any of those components would really "recombine" to make the number smaller in any realistic scenario, because I think that would require that they still be like, in phase and such(?????).
If by "recombine" you are just referring to the fact that the different parts are still added up : that's not really an event of re-combining that happens, that's just the fact that the different components (however you choose to split the hilbert space into components) are part of a single whole (which can be split up in many incompatible ways)
caveat [a] : I say this, but, while there are no doubt many valid decompositions into orthogonal components, it may be (as in, it might actually be well known to be the case, and it is possible that the only uncertainty here is because *I* don't know) that because of decoherence and stuff, that there is a natural decomposition, or at least more natural set of decompositions than most possible decompositions. I still doubt that there is a canonical way to define "how many worlds/components", because I strongly suspect that there are many things which are kind of borderline between whether it "should" be split up in a certain way, as well as like, precisely what mix of things should be used in splitting things up. But I could be wrong.
@@drdca8263 dr. dca, am i waste of space because im not as smart as you mathephysically? im not sure i deserve to exist if theres people like u walkin around 🥺🥺🥺 i have dyspraxia and tourettes so im incompetent and loud, and not a very interesting artist
Asking "where are the other worlds" is like asking "where did the other TV channel go?"
This is the basic plot device of how many science fiction stories, two separate dimensions somehow suddenly overlapping, or time travel stories where they have to manage the multiple different possibilities of various time travel scenarios.
PBS space is love ❤️❤️❤️
Hm, I was excited for the title of this video, since it seemed to be finally addressing a question I've always had about many worlds, which is "physically, how do the alternate worlds manifest in a decoherent spacetime?" but that didn't really get answered here.
That is to say, when, in many worlds, the universe's wave function splits, what happens to the other decohered universe? Does it cease to be and cease to affect/interact with our universe in any way? Or does everything in the split of possible observables get duplicated into another universe? Is it purely an informational split rather than a physical one? If so, how do we justify the physical manifestation and influence of *our* information as opposed to any other "world's"?
I imagine us three-dimensional beings are like babies, lacking hyperobject permanence XD
The other 'decohered' universe never existed and doesn't continue to exist. It is merely a possibility that never differentiated from the infinite noise of possibility. The whole universe is just static noise unless it is linked to you. Think of consciousness as pulling a signal from the cosmic microwave background radiation. You're consciousness has a specific position, nothing else does.
@@thegaspatthegateway oooh interesting!!!
I think what the original comment is referring to is the mind/matter problem.
Did matter manifest consciousness, or did spirit manifest physics?
this episode did answer the question where they are located. think back to that pond analogy. how multiple waves never were affected by each other. we one of those wave and the other worlds are different waves. they are decoherent with us which means those other worlds or waves do not have a definite phase relation to us or our wave. all the worlds exist in the same spacetime. just they cant interact with each other. basically instead of a single particle in superposition. the entire universe is in a superposition.
Question: Why isn't it possible to accidentally stumble back into phase, and thus bump into a ghostly other universe?
…It is 😈
@@kelpy582 Given strange eons?
i would say, if that happens, everything in both worlds fuse together and and endup being one, without anybody noticing it.
Deja vu?
you can't. you just switch worlds. or your consciousness just switches worlds for every decision you make.
Thank you so much for this episode. I've always wondered why nobody never asks this question to people like Sean Carrol, and I've always just assumed that it was obvious to everyone else but me...
I guess i spilled the coffee. Cheers from Argentina!!
I don't think anyone could convince me the "many-worlds interpretation" is our physical reality without a smoking gun.
In another world, they could convince you.
I don't see why you would think the Copenhagen interpretation would make even the least bit of sense. Waveform collapse may as well literally be "a wizard did it".
Maybe they were high on drugs when they imagined a many worlds state. Electrons simply ride along the wave and get distributed in the split experiment. Electrons with its atom structure dont stay in fixed location and are constantly orbiting or location affected by external environment.
I am your dad. Now give me back my wallet and car keys.
the only reason i believe in many worlds is because copenhagen is even worse lol
I geeked out so hard at the Magician's Nephew reference!
Greetings, fellow Narnia fan!
Love this guy.
How they showed Ghost in "Ant-Man And The Wasp" is quite accurate, it fits so well with this explanation. Also, it was big help for understanding this, because I could visualize the topic here with images from the movie in my head.
Peter Dinklage looks great these days
😆 nice. For real though. Matt's lookin good AF. Was shocked to learn his age lol
Not just linear, Linear Time Independent. LTI systems are critical for RF and small signal analysis which allow us to use the Fourier Series to analyze non-sinusoidal signals using sinusoids which are much easier to analyze since integrals and derivatives or sine waves but with an altered magnitude and phase - super easy to handle using complex numbers.
Haha, ahh. How dumb do I feel.
;-)
Nice Portal reference. One of my all time favourite games.
I used to champion the many worlds since I was a kid, but these days the amount of information and craziness it would required tends to make me doubt it quite strongly.
"Where are those worlds, and can we ever see them?" Sure, there are plenty of Isekai to watch each season... /s
Explosion
Bakaaa
They certainly are the latest anime fad
Japanese Manga writers have a keen ability to detect the Many Worlds.
Isekai kind of just represent the human dream of being able to exist in a wildly different world.
Joint + PBS Spacetime video = mind fking blown
Matt, the many worlds traverser we need.
Thank you!!!
I like that you added that we shouldn't take it on faith, nice touch!
Yeah. It may all be wrong and the Pilot Wave theory may turn out to have been the truth all along.
@@user-qv6oz3tc5o a disproof of many worlds would be so exciting
@@seionne85 A proof of many worlds would be more exciting imo
@@supermax64 to me it's cool to imagine what many worlds could mean. Specifically some quantum immortality consequences lol, but really if it's true it would just be kind of boring after the discovery. I mean unless there are some consequences I can't imagine. For me it's always more exciting when a top option gets taken off the table than when you get the answer
@@supermax64 my initial comment though was really just poking people who say many worlds is a religion.. or whatever they say
This is intimidating, extremely counterintuitive. My god.
Are you scared of the Loch Ness Monster?
Yeah sure I understood this 👍😬
(LOL. Great episode as always!)
Many worlds is one of the silliest things I've heard of. I am amazed it has any support. I hope I am alive when some clever people figure out what's really happening in the quantum world.
First Spin. Now Ripple. This just has to be a JoJo reference.
Araki knows something we don’t
That's also the training stages for the Rasengan.
@@kaizipaul quantam mechanics terms
Your Next Line/Video is...
...
Another JoJo Meme?!
@@kaizipaul most mangakas are fascinated by science and use it as inspirations for their magic systems
I remember being a young child, like 5 or 6, and wondering if every time I go one way, was there another me somewhere going the other way. I also remember wondering if we were on something’s tv just entertaining them
That being on TV part hits home
I was really obsessed with that thought as a kid. I always thought we're all being watched like how we're watching movies and reading comics
@@DumKump that’s weird that kids would think like that! Maybe we knew something back then that we’ve forgotten
Anyone remembers the episode Parallels from Star Trek: TNG? Now I love this episode even more. :D
Boy, you, err... picked a great day to post this, given Certain Events in Popular Culture that happened the day afterwards