Are Many Worlds & Pilot Wave THE SAME Theory?

[@elshadshirinov1633]

I really like to think of the "many-worlds" interpretation as the "one huge world" interpretation where you really buy into the concept of superposition. Instead of thinking of superposition on small scales, it acknowledges that everything is one giant messy superposition.

[@rtg_onefourtwoeightfiveseven]

Absolutely. Bryce DeWitt was a great guy but I fear his nomenclature didn't do the theory many favours. At least outside of popular science.

[@umbrascitor2079]

Same! So many people, even scientists and science communicators, dismiss MWI because it seems absurd that every quantum event should create an entire alternate universe. And yeah, that would be absurd. But if the entire multitude of possibilities exists as one sort of megaverse that contains every potential outcome, nothing needs to be created -- only selected.

[@semaj_5022]

This actually helped me wrap my head around the existentiality of "many world" more than anything else I've ever seen/heard, so thanks for that! Layered superpositions of probabilities and outcomes makes much more sense to me than the alternate "infinite branches" sort of idea.

[@Nathan-vt1jz]

I think that makes a lot more sense than the ‘new universe created at every quantum event’ version of the theory. I don’t know that I’d even call that a multiverse theory, more of some sort of universal wave field theory.

[@davidhand9721]

Bingo. I really hate it when Many Worlds is introduced as making new universes every time you flip a coin, because that's obviously ridiculous. I think it would be worth changing the name at this point. "One Big World" is okay, but I just tend to call it "Quantum Mechanics".

[@Jobobn1998]

Dude, the way the writers teed up the rhetorical dovetail from Pilot Wave to Many Worlds was a thing of beauty!

[@uninterestedcat8429]

Huh?

[@markaberer]

Dovetail? Like the bird? What does this video have to do with birds? I once fed a family of blackbirds, I hope they do well.

[@dragonrider7225]

A Dovetail is a kind of joint that holds itself together surprisingly well even without glue. en.wikipedia.org/wiki/Dovetail_joint

[@PrivateSi]

The theories are conceptually mutually exclusive so more confused BS from PBS Space Time, as usual.

[@danieljensen2626]

​@@markabererIt's a fairly common figure of speech for joining two topics together (based on the woodworking joint of the same name, which is of course named because it resembles the tail of the bird).

[@ericeaton2386]

The writing of this episode is absolutely *phenomenal*. The way the explanations build up on each other and slide so smoothly into the next segment is a true feat. E.g. "Fortunately I don't have to describe how our double-slit experiment looks in Many Worlds because... I just described it." Seriously, this is a skill. Most teachers don't come anywhere near this ability of connecting ideas together to create a cohesive picture. Bravo. P.S. I'm consistently impressed by the team's ability to reference previous videos as introductory to these topics. The catalog of videos spans many years at this point, and it's amazing how y'all are able to keep track of which ones apply to the current topic and direct people to them.

[@chasethevioletsun9996]

I'd agree. I read David Bohm's books and struggled to understand Pilot Wave Theory for a long time. This describes it super clearly.

[@shawnchong5196]

I disagree. Spacetime always makes it seem that the many worlds theory is possible or alludes it has any truth when in fact it's so fringe and cringy, it isn't funny. All best known credible physicists know Many Worlds Theory is trashy AT BEST yet this supposedly educational channel does not mention that the top physicists know Many Worlds is just garbage. I'm sorry but not mentioning a disclaimer that Many Worlds theory is absolutely trash. Therefore this is extremely clickbait, because MWT is absolutely fringe.

[@seditt5146]

Yeah but.... The particle creates the wave function and its an excitation of the guiding field and that is totally ignored here simply to make it seem like MW and PW are similar. They're not, they are nothing alike. The guiding function is calculated via the memory function which is the sum of the particles previous position backwards in time with all other wave functions in the measured area. It turns the uncertainty from amplitude and frequency to one of space and time. The accuracy of your future prediction is determined via the size of the area measured and the length of time it was measured. The larger the area, for the larger amount of time, the more accurate your future prediction is for a given particle over a given time. This video is gobbledygook simply to make MW people feel better about their pseudoscience theory".

[@ericeaton2386]

@@shawnchong5196 That... doesn't really address my comment at all. I was talking about their pedagogical skill, not the specific topic. Regarding the interpretations themselves, they all have issues. Obviously Copenhagen is by far the most widely-accepted, but they *did* acknowledge that at the start of the video. However, anyone who says that the Copenhagen interpretation is definitively the Truth is not a serious scientist who has grappled with the issues. The fact is that we don't have an entirely satisfactory interpretation for quantum mechanics yet. There are open questions, as there are for all areas of science.

[@shawnchong5196]

@@seditt5146 Exactly. Spacetime channel has released some very disheartening psuedoscience and questionable episodes that is very clickbaity and it's science sits on a table missing three legs. This video is a massive letdown as its pseudoscience sold as science without clear statement that everything stated here is just hocus pocus to most physicists but makes for good discussion For those that want real science, watch Dr. Lincoln's videos from Fermilab, no hocus pocus, just states facts and the general consensus of real physicists that have strong backing. MW is psuedoscience at its best, and many of the top physicists (incl. Penrose) have stated that MW is extremely murky at best. As soon as someone say Schrodinger's cat as a truly phenomenal potential reality = non-physicist. MW is basically this. Pilot theory though flawed at least isn't the hocus pocus of MW socery made famous from some book writers. Though the many research papers themselves gives very interesting insights.

[@victordebone7150]

Those are some very tricky visualizations, the graphics team deserves all my respect. As much as everyone else involved. I'd love to see a making of video. Thanks for the amazing episode!

[@n.butyllithium5463]

i'm happy to be in the universe where i can watch this video.

[@pierfrancescopeperoni]

Well, you're in all the universes, but only here you are happy.

[@goviczek]

@@pierfrancescopeperoni It depends on how do you define "you".

[@LuisSierra42]

In my universe, we look like trees

[@Deutungshoheit]

I mean it’s alright but I bet there are other universes where I’m way happier.

[@pierfrancescopeperoni]

@@goviczek Sure. The definition I use the most for "you" is "everyone".

[@_Mute_]

Im convinced this episode was written just to see how many times Matt could say "corpuscle"

[@maciejbala477]

you have to admit it is a funky word

[@mikebarnacle1469]

sounds gross dont like it

[@mikebarnacle1469]

it sounds like something you should get checked out if you find it on your foot and get cut off

[@Tore_Lund]

@@mikebarnacle1469 Despite it being decades since I was a teenager, I still have Corpuscles on my back.

[@philp4684]

Am I the only one bothered by Matt's odd pronunciation of the word, though? I've always heard it with the stress on the first syllable: COR-puscle, not the second syllable: cor-PUS-cle.

[@astrogames8645]

Always a good day when PBS Space Time uploads a video!

[@c.ladimore1237]

there are a handful of channels that really just make my afternoon fun & informative, and PBS pretty much never disappoints.

[@talananiyiyaya8912]

You're just jealous of her

[@shaneacton1627]

@@talananiyiyaya8912 Sabine?👀

[@TJF588]

What gets me about sci-fi that use "multiple worlds" is treating them as separate spaces, but the dogged impression I have is a single space which contains all the "material" for these variations to incarnate simultaneously yet mutually exclusively.

[@ricomajestic]

All the sci-fi multiple worlds I've seen usually happen in the same space though.

[@adamsmith6995]

As a retired physics professor, I really appreciate what you are doing here. I was never introduced to pilot wave theory in my teaching during the 1980's to 2010's. I was exposed to the many worlds concept, but more as an aside. I'm going to have to stludy these two in more depth to appreciate the connection. This video was an execellent intro that sparked my curiosity.

[@Mentaculus42]

But why spend much time on de Broglie-Bohm theory other than seeing it as the “Introductory Inspiration” for more modern theories that don’t have its limitations (non-relativistic, etc)? As a physics professor you should be fortunately equipped to grasp the “Weltanschauung” of the modern variants. There are multiple conferences that have many hours of videos on these topics. Some from Nobel Prize laureates.

[@mehrdadsalehimehr9849]

Which subject did you have taught the most?

[@Mentaculus42]

@@RockBrentwood One must be cautious about criticizing de Broglie-Bohm theory as it generates identical results to the orthodox theory that it is derived from because it is “effectively” identical! The “Oops” that you suggest are also not particularly within the scope of the “effectively mathematically identical parent theory” so what you are suggesting as fundamental problems are more about the overarching aspects of a “reality” based theory (whatever flavor of that it might be)! To address all your concerns in the context of the “new flavors” of “reality based” theories requires one to be conversant in these significantly more complex and sophisticated “flavors”. I use the term “flavor” as they mostly only borrow an “inspiration” from the “quasi-real” aspect of the original de Broglie-Bohm theory. I am not a defender of the de Broglie-Bohm theory as it is hopelessly antiquated and basically irrelevant in the context of your criticisms. If you are going to criticize “pilot-wave reality based theories” one really should put the “oops” in the context of the more modern “flavors”. Unfortunately, there is not much of a unified consensus on what that flavor should look like, so the comparison is challenging. The vary fact that a particular flavor has not gained much traction suggests the complexity of the “problem space”, but that should not hinder an open minded individual from pondering upon the possibilities of reality based theories. Personally I find my inspiration in Quasi-Hydrodynamic Quantum Field “Analogs” for want of a better name. There are variations of these “flavors” that fully subsume the “Standard Model”. The final trick would be to …

[@adamsmith6995]

@anolakes I agree with you more than it might appear. I was of the same mind in my teaching of the subject. Learn/teach how to use the science/mathematics to describe observations. Leave the more abstract and philosophical interpretation for later after you have mastered the basics. Yet it is still interesting to me to be familiar with these interpretations.

[@Mentaculus42]

@anolakes “ALL” interpretations not explaining “HOW” is rather inclusive! So you want a theory that has explicit “real” mechanisms to explain all QM phenomena (especially for nonlocality)! And while the big brained theory “contrive”ers are at it, to have mechanisms to explain all the “dark” stuff and be able to “compute” the values of all of those pesky experimentally “measured constants”. AND of course the theory needs to be “complete” and inclusive of General Relativity and thus deal with extreme energy densities at the Planck scales and handle “singularities” gracefully. It seems like that is a tall order considering the state of “ORTHODOXY” within the QM & GR communities and their “INTRANSIGENCE ON INCOMPATIBILITY” between themselves! What you are pointing out as issues have significant implications with regard to “FUNDAMENTAL UNDERSTANDING”. It will be a great day when we have that clarity of understanding BUT the preexisting state of affairs probably preclude that in the relatively near future. It is always entertaining (and sometimes educational) to listen to those promoting a “NEW INTERPRETATION”. There are some interesting newer concepts out there in the “fringes” that get to the “MEAT” that I suggest you peruse. It is always a fun endeavor as a hobby.

[@SupercriticalSnake]

Great episode! Aside from all the cool science, I also learned that the word "corpuscle" triggers an arcane nexus of negative emotions somewhere deep in my psyche. Neat!

[@scottslotterbeck3796]

Biology of the 1920s

[@Aiur]

Same 😂

[@Rogstin]

I'm just glad the initial configuration of waves and corpuscles gave us this channel and it's host.

[@thehappypittie]

I think I like the explanations for Matt not being available for questions at the end of an episode almost as much as I like Matt answering the questions at the end of the episode

[@rodrigomunoz6496]

Very few people in the world can explain these things as well as Matt.

[@AdnanCucak]

Well, the Writers Taha Dawoodbhoy & Matt O'Dowd I suppose

[@Merennulli]

Wait...in which world? 😅

[@AIJenkins]

If you can practice this presentation in less than three takes, your a genius. 💪

[@magnetospin]

I'll take your word for it, because I still have no idea what's going on.

[@ianalvord3903]

And it's a pity I can't understand half of it.

[@realzachfluke1]

I've been holding a special appreciation in my heart for Pilot Wave theory (and the people who've continued to work on it since its initial rediscovery, and fleshing out by David Bohm) since the very first time I saw Space Time's original breakdown of it. Funnily enough though, I've heavily disfavored Many Worlds for at least as long, if not much longer quite frankly, and yet here I am starting to appreciate some of the arguments they use to defend the Many Worlds position!

[@FelixPisecker]

it's kind of odd how the main argument seems to be that the core concept just sounds too fantastical to be real, and yet it seems to be the most physical closely related to the math. I never liked the hand wavy "and then the wave function collapses and that's just how it is" of copenhagen and the weird, almost mystical role it gives to consciousness, a biological phenomenon. Frankly I'm not educated enough to disregard it of course and most physicists seem to be on board so what do I know. I don't know if Matt himself is an adherent of MWI but if he's not it sure seems hard to make it sound unreasonable

[@davidwuhrer6704]

​@@FelixPiseckerCopenhagen doesn't give any special consideration to consciousness. That's a common misconception. Observation does not require a conscious observer. Any system that the wave interacts with counts as an observer and any interaction as an observation. Also, consciousness is not from biology. It's from philosophy. It is a subject of psychology, but it's not so much a thing as a hallucination created by other things, with the big mystery being unconsciousness.

[@Duiker36]

@@FelixPisecker IMO, the problem with Many Worlds isn't that it's too fantastical. It's that it's useless. Assume that there are many worlds: *so what*? That doesn't get us closer to understanding anything. It gives up on an explanation. Copenhagen at least has the half-credit of claiming that the world is fundamentally probabilistic, which is a claim that can have consequences. But Many Worlds has no consequences. It has no utility. "Fantastical" is an applicable word for describing that, but I prefer "pointless".

[@AwfulnewsFM]

​@@Duiker36there is no such problem, if both manyworlds and Copenhagen are equivalent. Any prediction about observables that Copenhagen makes is also made by manyworlds and vice versa. I.e. for any claim with a point they make the same predictions, they are either both pointless or both useful

[@donaldhobson8873]

@@davidwuhrer6704 If you have a particle in a superposition of up and down, and you set a second particle to measure it, you empirically get a superposition. Not a collapse. This is a testable prediction. Collapse doesn't happen in just from several particles interacting.

[@v4603]

I’ve been on such a Pilot Wave AND PSB Spacetime kick lately - I’m so excited to watch this lol

[@Kwauhn.]

What do you think, having watched it now?

[@captainbeefheart5815]

You're not gonna be happy lol

[@AndroidPoetry]

This video did nothing but demonstrrate anti-pilot wave bias. Pilot wave is still the best theory.@@captainbeefheart5815

[@AliothAncalagon]

I find it really interesting how the many worlds interpretation started out as the most outlandish concept for me and the more and more I learn about the fundamentals over the years it slowly seems to become the most elegant explanation with the least amount of extra "fluff" to solve problems.

[@ricomajestic]

Isn't all those worlds way more fluffy than all the other interpretations?

[@AliothAncalagon]

@@ricomajestic They are surely fluff, because you can't witness them, but their premise is as boring as it gets. It doesn't take a huge leap for beings who exist within a strand of silk, to argue that their strand isn't the only one that exists. The rest of the many worlds interpretation is basically just a string that consists of all the strands that could ever exist, slowly disentangling themselves into smaller and smaller strings until eventually every single strand is on its own.

[@SolidSiren]

I completely disagree as do most. MWI is the "fluffiest" of them all.

[@SolidSiren]

​@@AliothAncalagon I think a better word for it is lazy, personally. It's the most lazy interpretation.

[@AliothAncalagon]

@@SolidSiren You kinda contradict yourself here though. The most lazy interpretation is by definition the one with the least amount of fluff, since coming up with extra fluff is obviously not a very lazy thing to do. So what is it? Is it fluffy or lazy?

[@KekusMagnus]

good to hear another episode on Pilot wave theory, this channel is one of the only places I have seen that doesn't dismiss it outright. Most of my physics professors thought it was wishful thinking nonsence

[@stevenverrall4527]

As a physics professor, I am certain that both pilot wave theory and many worlds are utter nonsense. Not even wishful thinking. They are simply far beyond the bounds of plausibility.

[@rohanking12able]

​@@stevenverrall4527honestly every time people say many worlds. I say so nome of it matters then because how will we ever see the other without ripping space to apart to an infinite amount of worlds. Infinite energy and infinite negative energy. I'm just a 23yr old that likes learning new things I'm probably far off on my assumption but what are your thoughts

[@AwfulnewsFM]

​@@stevenverrall4527 still better nonsense than Copenhagen for sure

[@chaos120]

​@@stevenverrall4527Copenhagen sucks

[@viliml2763]

Well I hope that after watching this video you now understand that Pilot Wave Theory is really just Many Worlds in a state of chronic denial.

[@firefly618]

I love this video. I've been dabbling and grasping at these concepts for years (and watching Space Time for just as long) and Matt you outdid yourself this time. You're doing an amazing job! Thank you and please keep at it!

[@nijram15]

Amazing episode! I loved the teaser ending! Not sure if its due to the addition of the new staff, but I feel like space time keeps improving and improving. Awesome work guys.

[@AlmightyXI]

Been watching for years. since the old host, and this is definitely the best episode I've ever seen.

[@robisonlangdon8527]

The best channel on KZbin. I’ve been watching you guys for years. I’m so sorry I’m so broke.

[@bortol5113]

Nicely written and well explained. It would have been even better if you had acknowledged David Deutsch and his contribution in this issue and in particular in the argument that Pilot Wave is Multiverse in denial, which is a direct quote of his.

[@gene51231356]

How does Pilot Wave and Transactional Interpretation compare? Is TI just a more modern take on PW, or are there bigger differences?

[@cademosley4886]

In PWT you ditch locality. In TI you ditch one-way time. In TI, the wave function really goes off in all directions and entangles with the universe, but at arbitrary places of entanglement, a single particle travels backwards in time down only one path, so you get the appearance of PWT (looking at it forward in time) plus an intuitive explanation of the non-locality. There are a few catches to it. (1) The creator & advocates for TI even themselves don't think it's a realistic model. It's just a heuristically very useful one because it's easy to imagine & get an intuitive explanation for everything, and (2) it's in basically the same situation as PWT where it's contained inside of the MWI, where all the other worlds are still there and we're just privileging one of them because of our perspective. (2) In my view, the fact that PWT and TI are both "contained within" MWI, but not vice versa, as well as the informational interpretations (consistent histories, quantum Darwinism), basically all of them except objective collapse theories, speaks very much in favor of MWI.

[@kineticstar]

Every time someone simplifies the pilot wave and many world debate, I can't help but get that freaky and scary single election theory out of my head. Thanks, Matt!!

[@JohnnyWednesday]

It's probably that single electron in your head

[@cykeok3525]

If I understand correctly, as ridiculous as it is, single electron theory is still compatible with both pilot wave and many worlds; QM would simply mean that the spacetime path of that single electron (or positron, in its backward trips) is either simply guided by the pilot wave in the first case, or exists in a superposition of multiple possible paths in the second case.

[@PhilipMurphy8Extra]

Finally, It's time for great Thursday PBS Space Time

[@peterbonnema8913]

this video really cleared up for me what the differences are between interpretations. Thank you!

[@bierrollerful]

8:20 If a guiding wave continues on even after it "deposited" its corpuscle, and if guiding waves interact with other guiding waves... doesn't that mean that, over time, space gets super messy from all the waves that are still around?

[@EclipseCircle]

Perhaps this "mess of waves" represents entropy?

[@thedeemon]

Yeah, it's unclear what happens when particles are created and annihilated. Pilot wave seems hard to extend to QFT. And don't get me started on Unruh effect where the very notion of a particle seems observer-dependent.

[@drgetwrekt869]

that explains why its so hard to move through space to get to work

[@bierrollerful]

​@@drgetwrekt869 "Sorry boss, the density of guiding waves in my bedroom was especially high this morning, and they all led me back to bed. It was CRAZY!"

[@bierrollerful]

@@thedeemon Oh yeah, special relativity. Wouldn't that require that the guiding wave of the oberserver-dependent particle is dependent on the guiding wave of the observer? Sounds like quantum woo to me.

[@fraser21]

I can't wait for the self-locating uncertainty episode!! There's a lot of good content explaining the basics of Everett's online, but a dearth of good explanations for newcomers on the Born rule in this context.

[@pattucker7414]

I'm so happy this channel exists, thanks for another great video!!

[@some-say-gregms]

Amazing episode. It's rare that I learn something in a way where it was both easy to understand and yet also incredibly eye-opening at the same time. Well done Space Time team.

[@such_a_dork]

Random question it's never occurred to me to ask before: in the double slit experiment, what happens to the photons that miss the slits? Illustrations of the experiment always show all of the photons going through one slit or the other. But since we're not intentionally aiming them at a slit, there have to be photons that miss and get deflected. I wonder if those do anything weird. (If there aren't any misses, that's probably an extra level of mind-bendiness.)

[@mikemagnus9447]

That's a great question.

[@JustinMShaw]

The color of the material that the slits are cut into will give you some information about which photons were absorbed or reflected. And of course for each experiment you could check which colors were shone at the slits. I wouldn't expect much more interesting than 'slightly heated up the material' or 'bounced off of it' but it would be interesting to know all the details of what it does.

[@garethdean6382]

The photons that miss the slits usually aren't detected, they're blocked and count as 'failures', null detections. With the right choice of materials this can be minimized, such as using a diffraction grating rather than two slits. You CAN pair measurements of photons that miss the slits and the slit detectors, this shows that if a photon misses both slits then it doesn't go through either, which is what you'd expect. This has often been tried in 'blocked slit' experiments, where one slit had something to attempt to detect the passage of a particle, to see if that collapsed the possibilities. (And it seems to, no cheating there.)

[@catchphase]

I love the segue into Many Worlds here. Beautifully presented!

[@Danealor]

What a great episode! This further makes me believe that "many-worlds" is just a way of interpreting the Decoherence principle as explained in a previous episode. Where every possible superposition of the universe exists all at once in the same set of wavefunctions, but we only "see" one of them because that just happens to be the one our brains are in phase with, and everything else is noise that gets cancelled out. This seems to coincide with the principle of "many-worlds", where all possibilities exist but we just happen to be in one of them. And no assumptions are needed about "where" those worlds are, they're all right here, out-of-phase fluctuations in the wavefunctions themselves!

[@Matthew.Morycinski]

I once saw a holographic storage system where a single piece of film held multiple pages of text. When the reader moved, a new page would replace the previous one.

[@LMarti13]

As others have said, "Fortunately I don't have to describe how our double-slit experiment looks in Many Worlds because...I just described it." was perfect.

[@Valdagast]

I love the idea of an electron wavefunction being excited to meet its photon friend.

[@RobinOttens]

Excitedly bouncing up and down. It hears a car coming down the road, someone walking up to the front door. Is it my photon friend? Or just the mailman? We won't know for sure until they hit the detector!

[@rigelanderinvincent724]

The electron can't see the photon coming, it's already moving at the speed of information. The photo can't look forward to seeing the electron, it doesn't experience time at all.

[@gravelpit5680]

its mesmerizing how much yall put into these videos. thank you

[@Astromath]

This is simply a great video! Very well explained and visualised! I don't know what else to say

[@richardrhodes9664]

The fact that KZbin only recommended this to me 2 weeks after it released is why I for the first time ever have rung the bell for a KZbin channel. Never missing a video again

[@edwardlazell3157]

Great episode, I loved this one. I hope I'm in the right timeline to see the second part.

[@scottslotterbeck3796]

Sorry! Your timeline explodes into nothingness after nuclear war. Or alien invasion. Or someone pluls the plug on the simulation generator. Whoopsie!

[@sakurakinomoto6195]

In the beginning you mentioned the hypothetical possibility of perfect knowledge of the universe, but what universe do you refer to? The observable space? The space not yet causally separated from the observer? And at which time? The "present" of the observer or the observed present?

[@massimoc3442]

Great video as ever Matt! And speaking of hidden variable theories vs. no hidden variable theories, i remember you said that scientist are not in favour of them. Ideological resistance towards something we cannot know? Embracing hidden variable theories instead taking from granted that there aren't any, would physics change conceptually? I'd love an episode on this.

[@frun]

Physicists favorite interpretation of qm is Shut-up-and-calculate and was. Hidden variables have the possibility to change physics, we don't know for sure yet.

[@thedeemon]

It's not ideology, we have a mathematical theorem about certain inequalities that hold or not hold depending on whether local hidden variables are present, and we have many experimental results testing those inequalities, basically ruling out either locality or local hidden variables. en.wikipedia.org/wiki/Bell%27s_theorem

[@massimoc3442]

@@frun right… however I was wondering if all hidden variabile hypotesis are 100% unknowable or somehow testable.and so honourable theories one day

[@badlydrawnturtle8484]

@@thedeemon But it IS ideology to choose to dismiss hidden variables instead of locality.

[@frun]

@@massimoc3442 Some physicists consider HVT to be likely unknowable, but not 100%. On one occasion i read, that one physicist considered it to be plausible.

[@ZenonLite]

Thank you for doing this. I’ve been saying this for years!

[@samtheweebo]

In my head particles are just points of interaction between all the different waves in different fields. Imagine a stormy day. You get an electromagnetic field that builds up and then it "collapses" into a lightning bolt. Particles are just the point where the energy of the wave interacts with another.

[@harmonicpsyche8313]

Agreed! Taking Quantum Field Theory (QFT) at face value seems to suggest that a "particle" is just an excitation in a field at a specific point. I am curious whether we could take QFT so straightforwardly that we do not even have to admit the existence of particles, except as a convenient abstraction!

[@Kowzorz]

I remember seeing a fringe science youtube video a year or more back talking about something like this. They invoked superconductivity, not sure if literally or by analogy, to describe that "locus of action" sort of transfer of energy we would call a particle interaction. It would squeeze through the particle the same way I think of an octopus squeezing through a bottle opening.

[@samtheweebo]

@@Kowzorz I might be confused by what you are saying. Also how I understand the whole particle wave thing is likely wrong. Also I might not be expressing my thoughts clearly. What I'm saying is that particles are just the points where the fields are interacting. The wave or waves collapse onto the point where they interact. The point where information or energy is exchanged. Similar to how static charge suddenly collapses into a bolt of moving charge. Don't know how energy squeezing through a particle connects to my thoughts...

[@AlexanderFarley]

MWT seemed really appealing to me after learning about Multiple Hypothesis Tracking, which is a method of tracking multiple objects. It requires a branching-world model to track those objects and seems like a good model for understanding interacting continuous/discrete systems.

[@maxdoner4528]

Great episode! Eventhough the Argument here is in favor of many worlds and this kind of goes off from the point, I was curious how you can obtain Heisenbergs uncertainty principle in pilot wave theory. Is it a property of the guiding wave or the corposcules? I can hardly imagine either way, the wave is not measurable, so eventhough this uncertainty is a property of the wave, it can not really arise in measurement right? Or is it the guiding of the wave that causes this wave property to be transferred to the corposcule in every sense?

[@diogoduarte369]

The Heisenberg uncertainty is a property of our measurement methods. 3brown1blue explains that pretty well.

[@maxdoner4528]

@@diogoduarte369 I know of this thought Experiment that heisenberg i think came up with to explain the principle, where you hit the particle with high frequency light to measure its position accurately, thereby giving it a lot of momentum etc. But I allways thought that okay, this is a nice explanation of how the principle may manifest itself, but its not the whole reason for it. I mean can you rule out that there is some way of measuring that doesnt have this flaw? I allways thought that its very fundamental, like it really is impossible for These things to be fully defined without uncertainty. And that it mainly comes from the way the wavefunction works. Ie, for waves there is this tradeof between space localization and frequency localization. So you can not have only one frequency (which would be momentum here) without the wave being sort of everywhere. (You can Show all of this using the fourier transform and the gaussian wavepacket). Anyway, so I thought the principle arises from the math behind the wavefunction and that its very intrinsic, so I am Puzzled about where it should be in pilot wave theory. But perhaps it is a part of the measurement process?

[@Ultiminati]

​@@diogoduarte369no, it is a fundamental inequality of wavelike reality that we can also observe in Fourier transform.

[@mikehunt9392]

I think this is absolutely great, and makes leaps and bounds towards a unified theory. If only the cosmologist could be so understanding.😂

[@mehrdadsalehimehr9849]

I have a question, friend Why do you and many others want to summarize all of physics in one theory?

[@xValkyrie93]

This... clicked, wow. I've always enjoyed the Pilot Wave theory as to me it's something that seems so simple. The way it was tied in to Many Worlds as another theory that also just makes sense, was absolutely beautiful.

[@nanodan52]

The way I see it, the many worlds interpretation makes the most sense when you also consider that one of the fundamental laws of thermodynamics, that "entropy always increases" results in a forward flow of time. Entropy has many definitions, but the most useful in this context is thermodynamic entropy: the amount of "disorder" in a system, or, the # of alternate states of the system that are indistinguishable from the current state of the system. Something with high entropy has a high degree of disorder, randomness, and a large # of alternate macrostates that have the same degree of disorder. Low entropy means that there is only a few # of macrostates that look identical, or everything is highly ordered. If low entropy is low # of identical states (low probability), and high entropy is a high # (high probability), then the universe tends towards increasing entropy because the universe tends towards the most likely state. If every possible permutation of any interaction happens as in the many worlds interpretation, then in the incredibly vast majority of "worlds," the interaction moves the macrostate from a less likely state to a more likely state - entropy increases, and time flows forward! Just wanted to get my thoughts down. Super cool stuff! Love this channel!

[@drgetwrekt869]

you mean that many world preferred timeline is given by where entropy increases the most?

[@jaymethodus3421]

❤keep digging brother, when you get to bottom and the top it’ll be beautiful and ridiculous at the same time. Maybe even disturbing lmao.

[@Tomyb15]

​​​​@@drgetwrekt869no. There is no preferred timeline. There's many parallel ones, and (by the definition of microstate and definition of many worlds interpretation) there will be many more worlds with identical macrostates that correspond to different microstates with more possible configurations (ie "bigger" macrostates) than other identical but smaller macrostates, and these bigger macrostates correspond to the entropy increasing.

[@stefanogandino9192]

Entropy increasing does not make time going forward, otherwise in your fridge time would go backwards.

[@youtubedeletedmynamewhybother]

Definitely an interesting line of thought.

[@holden7117]

Love the videos. Started watching again because I heard of the double slit in time experiment and needed some refreshing on the original experiments. Would love to see a PBS Space time vid explaining the "double slit in time experiment"

[@KeyQuantum]

I wonder, would you be willing to cover the concept of Quantum Bayesianism?

[@amihart9269]

And the ensemble interpretation. I would like to see more epistemic interpretations. He only seems to cover ontic ones.

[@JesseGilbride]

Normally I am able to follow and absorb these videos in mostly one watch, but I have rewinded this enough to know this one will take more than a few watches. Kudos, Space Time.

[@rlstine4982]

What fascinates me is not that I learned about pilot wave theory in this episode, but that I had a quantum probability of understanding 80%+ of it, and nailed it.

[@GregorBarclay]

My wave completely collapsed after about six minutes…

[@EdwardChan.999]

Check out Veritasium's pilot wave theory video if you want to learn more :)

[@danieljmarvin]

How can you be sure you understood 80% of it without knowing what 100% of it looks like?

[@rlstine4982]

@@danieljmarvin because I watched 100% of the video and understood 80% of it. Basic math, I guess.

[@danieljmarvin]

@@rlstine4982 I'm messing with you. There is a good answer but I wanted to see what you thought. I don't think your point addresses my question though. I suppose You can get away with it by using definitions where 80% means times wise. But i think that's boring. For example, how do you know the the information at each moment of the video has the same importance?

[@johnp1]

Very good explanation of the Pilot Wave theory.

[@FunkyDexter]

7:27 What if the guiding wave doesn't affect the corpuscle, because it is "generated" by the curpuscle? Like in the droplet experiment shown by veritasium?

[@kevincronk7981]

I believe veritasium said himself that wasn't a fully accurate representation of pilot wave theory, just the closest he could reasonably make. My guess is that if the guiding wave was generated by the corpuscle, then some interferences between different parts of the wave function would act differently than they do in reality.

[@prophetrob]

The guiding wave is the interaction potential that the rest of the universe presents to the corpuscle and each interaction updates and propagates through the system relativistically The veritasium experiment was flawed in that all parts of the system weren't making their own contributions to the guiding wave. The system wasn't self-interactive enough

[@FunkyDexter]

@@prophetrob yes the droplet experiment is an example I didn't mean to say it was exactly like that. The question is why the corpuscle is not affected by the wave function but only by other corpuscles. This could be reasoned by having the corpuscle itself generate the wave function. Also, in QFT there is clearly a self energy term, meaning that the corpuscle is in fact influenced by its own potential

[@erobusblack4856]

I should point out based on this theory. Someone who completely interacts with no one and stays in full seclusion can experience all of these at the same time. And all possible outcomes are the same. Making them literally outside of possible spacetime

[@dmanagable]

IMO Many Worlds theory is the obvious answer to this "issue," the entire universe is itself in superposition and what we think of as our timeline is just one through line through this bulk of all timelines and possibilities, with every single quantum event "decision" guiding our timeline through the bulk. Each quantum event doesn't create a new universe on its own that would be silly, each one just guides our path, at the smallest scale, through the greater superposition universe in which we are embedded.

[@thedeemon]

Yeah, the main question then is who are "we" in this picture and how the heck do we see any changes in our world at all. Values of the wave function are not observable from within a "world" and in Schrodinger equation those values are the only thing that changes with time.

[@aguywithanopinion8912]

That is more or less exactly my feeling on the matter. Really it seems like all of the maths and physics is pointing to this description, and it is solely due to many physicists being uncomfortable with it (for no scientific reason) that it isn't more widely excepted.

[@chrisfrolik4014]

Yes indeed. The idea that the universe "splits" or "makes copies of itself" at each measurement point is completely unnecessary baggage to the theory. It can be simplified to exist without that baggage - that there aren't multiple copies of the universe, but only one universe that exists in a superposition/wave function state. Our entangled states simply prevent us from "accessing" other parts of the wave function.

[@solsystem1342]

​​@@thedeemon We can't know the exact properties of the particle but we can measure a range of possible values (our error in the measurement) and end up ruling out any possible states which don't produce that outcome. I don't know what you mean by "we". I presume you're asking if there is some sort of indivisible unit that you can attach to your observations to but in many worlds you just splinter the wave function and know what subset you're a part of. There's no way to observe just "yourself".

[@ubergroov]

Silly as it might sound to you, the idea of new universes springing from every quantum event is exactly what Many Worlds proposes. Your preferred theory that there is a true universe only works if there is a Great Observing Device whose observations determine which universe among the superposition of universes becomes real.

[@omarcadena6389]

one of the greatest episodes of all times!

[@Benjamin_Gilbert-Lif]

Yes more pilot wave videos!!!!

[@jimmyjasi-]

Is Pilot Wave the same as Everett? No. It's simple Parapsychology, Godels Theorems and Non-local Hidden Variables refute his philosophical nonsense. kzbin.info/www/bejne/rGbHkIaua7-ba80feature=shared

[@BishopStars]

I always thought PWT was compelling, but I was convinced that Many Worlds is a better explanation. Glad to see they're the same theory, and I've been consistent all along.

[@TravisChalmers]

I always have a hard time with "the wave function collapses". A blurry many worlds universe makes much more sense (as fantastical as it sounds at first), and we, as humans who are also blurry, only can experience one such world each.

[@jimsmith3715]

2:35 this is very true. I used to win a lot of bets when I was young because I could predict the side it'd flip to (id be flipping it, which was the main reason i won 90% of the time) i had just figured out from a very early age how to flip a coin reliably onto one face....

[@Nathan-vt1jz]

Great episode! I’ve been trying to wrap my mind around the possibility that the wave function is the base level of physical reality (holographic or otherwise). Some sort of integrated wave field theory. If particles are ultimately wave ‘packets’ that are part of the total wave, then I don’t see why multiple worlds would be needed and the ‘hidden’ variables would be the interaction of the larger wave field. This would include the particles, slits, ‘observers’, gravitational waves/fields, etc. Anyway, just trying to think through deterministic models that don’t include multiple, essentially infinite real worlds (I don’t buy the theory that every quantum position essentially creates a new world). I don’t mind the Copenhagen interpretation, but like to think about both explanations of quantum mechanics.

[@lukeewing4274]

But what is the basis for rejecting essentially infinite real worlds, apart from your persistent experience of only a single one (as would be expected given the many worlds interpretation)? Sounds like an argument from personal incredulity.

[@winonafrog]

👍🏼

[@MaryamMaqdisi]

I love you Matt. When I understand stuff it’s fascinating. When I don’t I get a great nap.

[@bzqp2]

I'm new to the pilot wave theory. How is it compatible with the Bell's inequations?

[@thedeemon]

1) Nonlocality: Pilot wave theory is inherently nonlocal. The motion of one particle can depend instantaneously on the position of another particle, regardless of the distance between them. This is because the pilot wave, which guides all particles, depends on the positions of all the particles. This nonlocality allows the theory to reproduce the quantum correlations that violate Bell's inequalities, despite being deterministic. 2) Agreement with Quantum Mechanics: Pilot wave theory yields the same predictions for experimental outcomes as standard quantum mechanics. So, it also predicts violations of Bell's inequalities just like standard quantum mechanics does. In other words, while it introduces hidden variables, those hidden variables don't lead to results that are at odds with the quantum violations of Bell's inequalities. 3) Hidden Variables: It's worth noting that Bell's theorem doesn't rule out hidden variables per se. Instead, it rules out a specific kind: local hidden variables. Pilot wave theory is explicitly nonlocal, so it's not in conflict with the implications of Bell's theorem.

[@bzqp2]

Thanks. When writing the question I missed the fact it was nonlocal.@@thedeemon

[@Richardincancale]

3:45 Love the logos for Pilot Wave vs Many Worlds! Must be a teeshirt design in there!

[@frun]

If one considers all possible initial conditions for corpuscles one obtains Quantum mechanics from Classical theory. Knowing the initial conditions one can reduce Many worlds to Classical theory/single world.

[@altrag]

Sadly no. The choice of which "world" you end up in at any splitting event is exactly as non-deterministic as the wave function collapse from Copenhagen. You can assert that there is some world that would reduce exactly to classical mechanics if someone could trace all the interactions closely enough, but you can't know whether or not you happen to be in that world (and given that MWI splits into infinitely many worlds, your probability of being in the exactly classical one approaches zero very quickly).

[@victoriaeads6126]

Every time I watch a Space Time video, my mind gets stretched, poked, prodded, and pushed in different ways. In my opinion this is the entire bloody point, so thank you quite kindly!

[@victoriaeads6126]

As an aside, the "Perfect Knowledge" stock image guy looks like what would happen if the dumba$$ HC "ancient aliens" bonehead was actually a real sciee. A scientist with high functioning brain cells... And decent hair.

[@ichbinein123]

It took me about 45 minutes to watch this episode, with countless rewinds, but I've had SO many questions about Quantum Mechanics suddenly make sense! One of the best videos you've ever made to date!

[@irokosalei5133]

I have an analogy for quantum systems using sudoku. When the grid is empty is is like no interaction or measurement are happening, any cell could contain any number as would a wavefunction in superposition or states. When you set a value in one cell , the possibilities drop in the related cells like they are tangled particles .

[@winonafrog]

I appreciate this analogy

[@hectorh.micheos.1717]

Came in convinced (as a layperson) that Pilot Wave was the simplest interpretation, came out thinking it is Many Worlds... Now I wonder which ones of my other selves think the same as I do.

[@solsystem1342]

I think it's impossible to describe the "simplest" story about the math. But many worlds certainly works the best for me conceptually.

[@prophetrob]

Many worlds sounds simple because they threw the baby out with the bath water and that's why they can't tell what's happening

[@Merennulli]

@@prophetrobThere was no baby, just a superposition of quantum excitations in bathwater.

[@amihart9269]

It's because these videos all ignore the ACTUAL simplest interpretation which is the ensemble interpretation. The Many Worlds Interpretation relies on two arbitrary assumptions that are not justified. First, it interprets the probability distributions encoded in the wave function of where a particle can go as all real physical paths it actually takes, which is not justified at all. It then has to explain how, if the observer can be on many different branches, how do they predict which branch they will be on? To answer this, the MWI then has to copy/paste the Measurement Postulate from the Copenhagen interpretation and claim that you just update which branch you're on based on the result of the measurement, which is logically identical to the "collapse" in Copenhagen that says you just update which value is selected from the wave function based on the measurement result. MWI has equally as many postulates as Copenhagen, and pretending otherwise is just being intellectual dishonest. Both Copenhagen and MWI rely on a variant of the Measurement Postulate because both of them rely on an arbitrary additional assumption that the beginning: that the probability distributions described by the wave function all physically occur. There is no reason to assume this, that we wave function has any ontic existence. Quantum mechanics is just a form of statistical mechanics, it is probability theory, the probabilities describe where you _think_ it might go in reference to your knowledge. It is a predictive tool, entirely epistemic, and the paths it does not take has no physical existence _at all._ Whether or not pilot wave is inherently broken like this, to me it would depend on whether or not pilot wave could be reinterpreted as an epistemic theory rather than an ontic one, that the "ripples" each individual corpuscle creates does not equal the whole pilot wave, but that the pilot wave can only be derived from a summation of all the ripples from all the corpuscles (i.e. they would each have a pilot wave that is a subset of the one predicted by the Schrodinger equation where the full pilot wave can only be derived from a large sample size that converges towards the pilot wave predicted by the Schrodinger equation). That would get rid of these "phantoms" because they'd never exist in the first place, although I do not know enough about the mathematics underlying pilot wave to whether or not it could be reformulated as an epistemic theory. Epistemic interpretations, i.e. _ensemble_ interpretations (sometimes called statistical interpretations) are the most sensible, but they are always ignored. Everyone wants to assign borderline mystical entities to probability distributions and then argue over which entities are "the simplest," when none of them have justified why we are assigning these entities in the first place. The ensemble interpretation does not introduce any new axioms that were not already in classical theory. We just accept the probability theory in quantum mechanics is what it looks like: probability theory, and nothing more, and then you no longer have a Measurement Postulate like Many Worlds and Copenhagen do, nor do you have bizarre entities like infinite universes or whatever. Like in any probability theory, there is no reason to posit hidden variables because the whole point of statistics is to account for the fact you don't know the hidden variables, you do not even have to posit things like "pilot waves" but you leave it as an open question that no answer can be justified unless it can also be falsified (which none of these other interpretations can be).

[@Rebel7284]

@@amihart9269 what are the drawbacks of the ensemble interpretation? I suspect that if it really resolved all issues, we would talk about it more.

[@kerycktotebag8164]

i love it when people help me connect seemingly disconnected ideas bc i don't have the readily-familiar granular understanding to make such connections

[@hotrodandrube9119]

A friend of mine had to have a corpuscle transfusion after a bad wave riding experiment accidentally went through some slits. Nobody was watching the background radiate.

[@RealmsOfThePossible]

Health and safety in the quantum field is a nightmare! Theoretical quantum kneepads are a joke as you can't get the damn things to break super position and they end up all over the place.

[@DouwedeJong]

Thanks for making this video. I learned something today.

[@Wesyan1999]

I still don’t quite understand how can Many Worlds be the same as Pilot Wave, since Many Worlds doesn’t feel deterministic, or is there something that determines in what timeline will I land?

[@Piranath]

A version of you lands in each timeline and each is a continuation of your past self. From a subjective perspective it seems random because you(a continuation of your past self) only experience one of the possible outcomes but the other outcomes are being experienced by other equally real continuations of your past self.

[@Wesyan1999]

@@Piranath so does the question "is the universe deterministic" even make sense in Many Worlds since all possible outcomes happen? Or do the timelines split the moment that Laplace's Demon has enough information to determine what will be the outcome? Does that mean that when a Laplace's Demon starts existing all timeline splitting that would happen in the future happens in that instant?

[@Piranath]

@@Wesyan1999 From my understanding the timeline splitting(sections of the waveform de-cohering) happens regardless of observation/knowledge. Observers(like us) will percieve it as being related to observation because they are observers but that isn't the fundamental reality. If you consider the universe the waveform as a whole then it would be accurate to say it is deterministic because all possible outcomes happening is in fact the only possible outcome{ie it is impossible for any possible outcome to not occur} of the waveform as a whole.

[@WGH9392]

Your videos are amazing. They take these high-brow concepts and make them so chewable for those with minimal physics backgrounds. The only issue is, that watching your videos tires me out. Every hour of your videos I watch knocks me unconscious for two hours. I love watching and having my mental horizons expanded, but I can only watch on weekends because just 2-3 of your videos will eat my entire afternoon.

[@TonyO8187]

I think I've officially learned more from this channel than my entire undergraduate physics program.

[@scottslotterbeck3796]

Because it is explained better.

[@Duiker36]

@@scottslotterbeck3796 It's also covering a lot of topics that aren't in most undergraduate physics programs. Easier to be better than nothing.

[@Kirkaiya]

Great episode! I'm looking at the merch store, and saw "Be quiet, the devs will notice" T-shirt. Is this a reference to simulation hypothesis? Or what?

[@frogandspanner]

Interpretations are not theories. They are means by which we can feed our internal models, our intuitions, the tools that help us cantilever our understandings. We can use interpretations to help us build new hypotheses, but the interpretations themselves have no _direct_ value. The more interpretations we have the greater our ability to intuit. So: bring them on!

[@mmandrewa2397]

It could be that you have it backwards. And that these interpretations are the only real theories. Or to say it in another way, if you don't have understanding, then you don't have a theory.

[@frogandspanner]

@@mmandrewa2397 I disagree. A theory is only about predicting - including _post hoc_ predicting (aka explaining).

[@amihart9269]

I wouldn't consider pilot wave theory to really be an "interpretation" since it is not just a way to visualize the mathematics of quantum mechanics and what it means, but posits a whole new theory of what underlies quantum mechanics and a whole new body of mathematics to describe how these new entities behave. Bohm also stated he thought you could come up with experimental tests with it, such as he thought that even though knowing a particle's position precisely is not possible, if you repeated an experiment many times in rapid succession under an isolated environment, you might get close enough to the same starting point on some of them that you could see violations of the Born rule. I put pilot wave theory in the same realm as string theory, it is not an interpretation but a whole new theory, just one without any evidence for it so there's no reason at the moment to replace any well-established theories with it.

[@mmandrewa2397]

@@amihart9269 I sort of agree with you, but the Copenhagen Interpretation, the Pilot Wave Theory, and the Many Worlds Interpretation all predict more or less the same thing. I don't think we can really say that one is more established than the others. If you're talking about popularity, yes, the Many Worlds Interpretation is the most popular theory. But I don't think that makes it any more well-established than the others . (And then there are the other theories we aren't talking about.) And by the way on the subject of the Copenhagen Interpretation, that theory depends on something called an 'observation' and something called the 'collapse' of the probability distribution when an 'observation' occurs. And neither one of those ideas is well-defined. That's why some people would say that the Copenhagen Interpretation is not a true theory. If you have key concepts that are not objectively defined, then that's a problem.

[@amihart9269]

@@mmandrewa2397 MWI and Copenhagen are not theories. They are interpretations, they try to come up with ways to think about the mathematics of quantum mechanics and what it means, but are not introducing some a whole new theory "deeper" than quantum mechanics and to my knowledge no advocate of them has ever even suggested it might be testable.

[@jogandsp]

I would love love love love love love love for you guys to make more content about pilot wave theory!!!!!

[@kevincronk7981]

Always glad to hear more about pilot wave theory, imo it combines the math of quamtum physics and the philosophy of determinism, which just feels more right than the universe being inberently random. Everything we've ever found has been pointing more and more towards detirminism, then quantum physics cones and changes things. Imo it makes more sense to change the 1 outlier than everything else.

[@KekusMagnus]

there are superdeterministic theories which don't require pilot waves too, but they are untestable so no one pays attention to them

[@innocentsmith6091]

It only feels right because you were destined to feel that way.

[@maxweber06]

First off, I think it's a bit selfish to want THIS universe to be the one universe that's real while considering all others as ghosts. But, the underlining effect existed before quantum physics and before humans which you can not just deny it's existence, the split happens even if seconds are between each particle. You can either treat all universes as equal, and you find yourself in a random one, or you break locality and causality with it by allowing faster than light communication, which introduces paradoxes. However, you can have your determinism cake and eat it too. If you consider each universe equal and real, then anything that can possibly happen happens, will happen, and if everything can happen, then all possible timelines are completely "explored" and mapped through time. The path you take in life is then also real and explored creating a deterministic flow of time that is shared between all timelines. And what I found nice about this interpretation is that it allows me to pursue life by trying to be the best version of myself, while statistically I'm very likely to be not living my worse.

[@badlydrawnturtle8484]

@@innocentsmith6091 That's a misunderstanding of determinism. The determined path isn't randomly selected. A simplified example would be a rabbit choosing to eat: The deterministic explanation is that it's eating because it feels hungry; not out of some ill-defined "destiny". People like me believe determinism is a good bet because we evolutionarily evolved to have the ability to reason, and reason has lead us to that conclusion; not "because destiny".

[@Piranath]

Many Worlds Interpretation is still deterministic when you consider the whole wave function. It just seems random subjectively because each possible continuation of your past self only experiences one of the possible outcomes. But all possible outcomes still happen and equally real continuations of you experience each of them. The Copenhagen Interpretation is non-deterministic because it says that only one of these outcomes happens and doesn't provide a deterministic mechanism to determine which one, but in Many Worlds it is determined that all possibilities occur and that is deterministic.

[@michaelwinter742]

My favorite episode to date - and that’s a high bar. Bravo! 👏

[@calculon000]

The Many Worlds interpretation has always seemed to me to be the most obvious in terms Occam's Razor. "They all happen, we are just experiencing one of them." seems much simpler than trying to invent some elaborate mechanism to square the circle of translating the probability of waves into the determinism of particles.

[@aelolul]

The One World interpretation has always seemed to me to be the most obvious in terms Occam's Razor. "Only one happens, our theory just enumerates all of them." seems much simpler than trying to invent some elaborate mechanism to square the circle of translating the determinism of particles into the probability of waves.

[@SiEmG]

@@aelolul the beautiful symmetry! i shouldn't have commented, oh sit..

[@kindlin]

@@aelolul But then, how do all the ones that don't happen have an affect on the one that does happen?

[@SmileyEmoji42]

Many people I talk to, wrongly think that many worlds = multiplying by an infinite number of extra things and hence failing Occam's razor when, in fact, it is just one thing for the purposes of the razor and hence simpler than all the other explanations.

[@gianpa]

​@@SmileyEmoji42I think they're both simple enough that Occam's razor doesn't really mean much here... It's like saying that there's definitely just one universe because adding another one will increase complexity. Nonsense....

[@eunomiac]

I've always liked the pilot wave theory. It's a lot easier to grok than many worlds or superposition/collapsing probability ways. Just seems to comport with my idea of how reality "should" work, I suppose :)

[@absolutedisgrace]

The born rule reminds me of the inverse square rule with area. Like how we could determine the number of dimensions in how gravity drops off over distance. This seems to suggest that for many worlds, those worlds are just another dimension to our known 4. I.e 3 dimensions i space, 1 dimension in time and this new dimension in lateral time. Just like how a single particle exists throughout time, where you are in time is linked to where it is in space. Move laterally in time and it moves across the wave function.

[@oravlaful]

you look like niels bohr

[@Morgan-rh3rc]

You're one the right track but a few details are off. The branches of the wave function are not another dimension on the spacetime manifold. Instead the way to think of it is that our 4D spacetime is a submanifold embedded in the larger space of all the states the universe could be in known as Hilbert space. Hilbert space is an infinite dimensional flat manifold in which each normalized point in Hilbert space corresponds to a possible configuration of our 4D spacetime and its contents.

[@borisborcic]

My reaction to the title question before watching : "of course not", and wonderings follow;) On second thought, the piloted particle could populate unseen shadows of the snubbed dimension of many-worlds -- with many-worlds you are *not* meant to ask, "what is it that selects the option of my very own experience among the many possible contrasting experiences that the model finds comparably likely?", and that's where the convoluted trajectory of a wave-piloted particle might hide!

[@grawl69]

"Many worlds in chronic denial" is a perfect description of pilot wave theory, made by David Deutsch.

[@protocol6]

What if the influence of the corpuscle on the guiding wave is very small but not zero? What kind of limit can we put on the scale of that influence based on experimental results? It seems clear from the bouncing droplet experiments that there is a bidirectional influence in that model, though that could just be where the analogy breaks down.

[@NewMessage]

Either way, we're in the bottom 10 of of Multiverse Today's 'Top Underserses to split off into' list.

[@GGoAwayy]

Bottom 10 out of infinity is a pretty impressive underachievement.

[@NewMessage]

@@GGoAwayy Hmmm... fair point.

[@jimmyjasi-]

Is Pilot Wave the same as Everett? No. It's simple Parapsychology, Godels Theorems and Non-local Hidden Variables refute his philosophical nonsense. kzbin.info/www/bejne/rGbHkIaua7-ba80feature=shared Not only Pilot Wave is not the same as Everett but on the contrary it's the only Interpretation that refute him in profoundest way. Unlike Copenhagan or even Objective Collapse it explains why only one of supposedly Infinite possibilities is realized... And the answer is... Because we gave up Determinism and Realism to early!

[@GSPV33]

Really appreciate you and your team.

[@jounik]

The main problem with _any_ interpretation of QM is that while quantum mechanical observables are, by construction, invariant under time reversal, they are built on phenomena in an inherently chiral spacetime, which should mandate a sign change somewhere on time reversal.

[@mymyscellany]

thinking about it from this perspective, would some sort of reverse causality where the future influences the past avoid this problem?

[@anywallsocket]

It’s not obvious whether it’s interaction that’s not T symmetric, or the laws themselves.

[@debrachambers1304]

The word "corpuscle" sounds kind of funny to me for some reason. Corpuscle. Ha ha ha!

[@Steevo69]

It's sounding more and more like space is a super fluid. And that's what sets the speed of photons as well as their interaction and the Electromagnetic field interaction

[@davidtatro7457]

This is one of those PBS Spacetime videos l happened upon under the influence of a couple glasses of wine and decided l had better archive it and watch again later so that l do not get completely lost!

[@Dominic_Berry]

The Copenhagen interpretation does not actually violate locality, because it is what is called an "epistemic" theory, which means the wavefunction describes your state of knowledge. The "collapse" of the wavefunction just means that your description of reality has changed due to the information you gained from the measurement. Your description of reality is just something that happens at your location, it does not in any way change reality at other locations. In contrast Many Worlds is what is called "ontic", meaning that it is now interpreting the state as corresponding to reality, rather than just knowledge. This also means it is consistent with the Copenhagen interpretation, because an observer can be regarded as being described by an overall wavefunction. The observer can only interact with part of the overall wavefunction, so can only use a wavefunction to describe their state of knowledge, not the overall wavefunction that they are a part of.

[@NikolayCherednychenko]

This is an amazing explanation of the Double Slit Experiment!!!

[@kobayashimaru8114]

Since we're invoking Occam's Razor, would it be simpler than Many Worlds to say that all possible arrangements of fundamental particles exist simultaneously in a timeless state? Our most likely experiences would then be a probabilistic path through this landscape in accordance with Born's rule.

[@QuantumOfAwesome]

“Timeless” is maybe too strong a word though - true eternalism (which I think is what you’re getting at, in terms of block universe variants?) requires that the future is predetermined. I’m not immediately sure how to reconcile the ideas that Many Worlds is non-deterministic *and* somehow equivalent to (the deterministic) pilot wave theory, though.

[@Piranath]

@@QuantumOfAwesome My understanding is that in Many Worlds Interpretation the wave function as a whole is deterministic. It is just that from a subjective perspective it doesn't seem deterministic because there is a version of the observer in each "world" and each version will only experience one of the possible results, but all will still happen just in different equally 'real' 'worlds'. Pilot Wave Theory adds the corpuscle to the model as a deterministic factor that determines which 'world' is 'real' to keep it deterministic without many 'worlds' being 'real'. Copenhagen Interpretation arbitrarily decides one of the 'worlds' is 'real' and the others stop existing and that decision isn't deterministic. If I'm wrong about any of this please correct me.

[@QuantumOfAwesome]

@@Piranath ah that makes sense. I guess from that perspective, all options but the Copenhagen interpretation are wavefunction-deterministic 🌊

[@altrag]

@@QuantumOfAwesome The wave function is equally deterministic in all interpretations. And the final result is equally non-deterministic. The interpretations just differ on how determinism least to non-determinism: - In Copenhagen, the state the wave function collapses into is non-deterministically chosen based on the probabilities given by the wave. - In Pilot Wave, the guiding wave provides the set of paths the corpuscle can take, but the choice of path is non-deterministic. - In MWI, which universe you happen to be in is a non-deterministic selection. And in all interpretations, there's a path to reintroducing determinism by knowing more about the underlying function of the universe: - In Copenhagen, we would need to know the details of how wave function collapse proceeds. - In Pilot Wave, we'd need to know how the corpuscle chooses among the possible paths presented by the guiding wave. - In MWI, we'd need to be able to inspect the state of the parallel universes. All three reintroductions require some form of knowledge about the universe that we not only don't have, but are likely fundamentally unobtainable within the bounds of our current models. The only real way out of the dilemma is to discover whatever deeper theory lies beyond our quantum mechanical description of the universe, and hope that it doesn't have the same problems or we get to rinse and repeat.

[@moses6486]

you characterized the existence of a true world line as the least likely. That's excellent sophistry

[@josephhall5681]

You gotta love seeing a new episode posted. Matt has a gift when it comes to explaining complex theories about and phenomena happening in our observable patch of Space Time.

[@ozanerhansha]

When I was in college, I took a class on the philosophy of physics. One lesson that shocked me was that classical physics (as we might usually conceive of it) actually *isn't* deterministic (see Norton's dome and space invaders). Although, I guess this says more about the ill-definedness of classical physics than it does anything about the foundations of quantum mechanics.

[@drgetwrekt869]

it isnt if you have only a finite resolution of how much you can measure. but fundamentally it is. tho its essentially not computable.

[@chriscurry2496]

@@drgetwrekt869 Please see Norton's Dome. That thought experiment alone seems to suggest that Newtonian physics is NOT deterministic fundamentally.

[@MrFanservice]

I'm definitely no scientist, so this'll will probably be hard to understand on first read. But when it comes to the Born Rule and why you need to square the amplitude of a systems wavefunction, my intuition tells me this is because of how we perceive a map to work. So when it comes to maps/instructions on where to go, there are two immediate ways that people usually go about it. First one being; you just give a list of written instructions. Now obviously the quality of the description does matter in this case, but you know exactly what I mean if you've been on the internet for a while. In the past having to go online to whatever site, find the written out directions (street names, directions to turn, distances, general timeframe, etc) and it LITERALLY being in list format. You'd have to print this off before going on a long car ride, and god forbid you lose that piece of paper. Nowadays we're more lucky and pretty much everyone is able to use the secondary form of maps, that being true 2D models of the actual area you'll be traversing. Being able to actually see where you need to go before you even get there. Clear difference in the two methods. One more clearly tells you exactly where to go/what you're looking for. And the other does pretty much the same thing, only its harder to interpret due to it missing a kind of context. Think of the wavefunction amplitude in the same way. Taking the value on it's own, it only really tells you "yes, this system can indeed take many forms". You need to square that value in order for the many forms to be more apparent and viewable. You need a secondary plane in order to have a place to represent these different forms and outcomes