Zeno's Paradox & The Quantum Zeno Effect

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“A moving arrow is at rest.” This is obviously a nonsensical contradiction. But Zeno, a Greek philosopher famous for his metaphysical trolling, devised a paradox whose conclusion is just this. Here’s how it goes: if you look at an arrow flying through the air at any instantaneous snapshot in time, the arrow doesn’t travel any distance. If time is composed of an infinite number of these snapshots, and the arrow doesn’t move in any of them, then the arrow is at rest during the entirety of its flight. The moving arrow is at rest.
In fact, if we’re talking about a quantum arrow, there may be a way to freeze its motion simply by looking at it, through the aptly named quantum Zeno effect. The quantum Zeno effect predicts that certain quantum events - like the electrons moving between atomic energy levels, or the decay of atomic nuclei, can be frozen through the simple act of observation. I’m going to tell you about some very real experiments that claim to have demonstrated this phenomenon. But first, let’s see if the quantum Zeno effect can save us from being shot by a quantum arrow.
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Written by Katie McCormick & Matt O'Dowd
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[@bierrollerful]

Kids: "Are we there yet? Are we there yet?" Parents: "Stop quantum freezing the car!!"

[@glypheye]

😂. You need two kids, one in you left ear and one in your right, perennially asking “are we there yet?” You never left......you never arrive. Just the endless journey, purely observed.

[@jeshii]

Underrated comment

[@TheRABIDdude]

A surprisingly clever joke. Nice job!

[@andrejandu7181]

haha top joke

[@joejohnson3582]

Ooooh so that explains the collapsed brain function while setting off on a family vacation....

[@jacquelinejohns9838]

Did you just describe Zeno's paradoxical ideas as 'trolling'? It all makes sense now.

[@alkestos]

All the so called great philosophical minds of the past have been nothing but trolls but it went so far over the heads of normal people back then they thought it was somehow profound. You just solved philosophy. Like you know, one does...

[@voidisyinyangvoidisyinyang885]

We present a measure of quantum coherence by employing the concept of noncommutativity of operators in quantum mechanics. We analyse the behaviour of this noncommutative coherence and underline its similarities and differences with the conventional measures of quantum coherence. The maximally noncommutative coherent states turn out to be far removed from the conventionally considered maximally coherent states. We argue that the efficiency of the quantum phase estimation algorithm, an important rung in the Shor factorisation algorithm, is potentially related to the measure of noncommutative coherence." Matt O'Dowd just needs to dig a bit deeper - he's Anti-Trolling.

[@spawnsen823]

@@voidisyinyangvoidisyinyang885 was about to say that.

[@winonafrog]

*metaphysical trolling !

[@skyebluee]

"We do a little metaphysical trolling" -Zeno

[@BarteG44]

I am in immense pain

[@hiccup3.14]

"If someone shoots a quantum arrow towards you, don't blink" One of my favourite quotes

[@JonathanScarlet]

The best part is the freeze-frame of a Weeping Angel right after it.

[@hiccup3.14]

@@JonathanScarlet A watt?

[@JonathanScarlet]

@@hiccup3.14 Re-watch at around 4:59. Blink (or not) and you'll miss it.

[@hiccup3.14]

@@JonathanScarlet ahhh ok, Thankyou very much

[@liliwheeler2204]

As soon as he started talking about looking at the arrow to stop it from hitting you, I figured a "don't blink" reference was inevitable was (unlike being hit by a quantum arrow)

[@seionne85]

You got me there after "don't blink" lol

[@LuisDiaz-qg3eg]

He wouldn't if you hadn't blinked

[@MultiverseMediaSpace]

Doctor?

[@jeremyleyland1047]

And the angles wept

[@TheHolm]

I frikkin hate those!!!

[@StephenHodgson]

I laughed for about 5 min straight. Part of why I love this channel

[@ayehavgunne]

I used to be a spacetime adventurer like you but then I took a quantum arrow to the knee. Because I blinked.

[@innocentbystander3317]

The quantum arrow never existed until you observed it anyway, so technically, not only did you do this to yourself, but you also confirmed that this is how you wanted things to be by blinking. Kids these days... Well, at least you're still alive.

[@user-ut3ni6bu7b]

no lollygagging

[@anmolmehrotra923]

Ever thought about the second entangled arrow with it? It may have tunneled and hit another adventurer of space-time. And you know what he didn't even blinked! But you only think about yourself 🙂

[@arnabmukhopadhyay7078]

Lemme guess someone stole your quantum roll?

[@innocentbystander3317]

@@anmolmehrotra923 I too used to be a pan-dimensional being, until I took a quantum arrow to the knee...

[@misakilive6010]

Spacetime is the best channel on this whole site. This series is amazing, and you're a great host, Matt! If I ever get around to getting higher education, I know what I'm studying!

[@slevinchannel7589]

Try also: -Veritasium. -Its ok to be smart. -Neil Red. -Sci Man Dan. -Sci Show. -Practical Engineering. -Hbomberguy!!

[@ChaineYTXF]

if you do end up studying physics, fair bit of warning: you're in for a treat.

[@vauchomarx6733]

@@slevinchannel7589 HBomberguy is great! A very different genre though…

[@slevinchannel7589]

@@vauchomarx6733 Yep

[@vauchomarx6733]

PBS Spacetime is cool, but imo, there are even greater physics channels out there. Physics Videos by Eugene Khutoryansky (kzbin.info) has some beautifully made animations, which gave me a much better intuition for understanding that sort of stuff, I heavily recommend checking them out!

[@PatricioHondagneuRoig]

0:20 "Metaphysical trolling". I love that way of putting it.

[@keith8554]

Famously

[@pauldacus4590]

4:59 Never let a Dr Who reference go to waste!

[@hjk3927]

Weeping Angel from the episode "Blink" ;)

[@benedictul]

I was expecting the angels to make an appearance, wasn't disappointed.

[@INGIE32]

Can anyone explain the reference?

[@benedictul]

@Franky Padilla baby don't hurt me

[@MrOlecomte]

@@INGIE32 It refers to an iconic Doctor Who episodes called "Blink", where the antagonists (aka Weeping Angels) can only move when they're unobserved. So to survive them the rule is simple: keep your eyes open and don't blink.

[@ThierryTiramisu]

0:20 metaphysical trolling. Quite badass, Zeno!

[@blackmamba1261]

That's the first time I've heard it referred to like that, and I love it.

[@Cythil]

@@blackmamba1261 Well. From what I understand is a pretty good description. A lot of philosophers seem to have been annoyed at Zeno. Even some contemporary ones to his own age.

[@jorgepeterbarton]

The effect of "not sure if really dumb, or just proved the whole universe wrong" type stuff.

[@Cythil]

He is one of my favourite philosophers. I am not sure what that says about me... >_>

[@Cythil]

@Baka Mitai Oh, he is a fun one to. Has a fascinating idea what makes for a good home. ;)

[@mjassims]

“Observing a quantum object; observing an image of a quantum object. These are the same” - Tower of Quantum Trials

[@aluxt]

If the Quantum Zeno Effect plays a role in birds' ability to see magnetic fields, then does that mean (according to the Many-Worlds interpretation) there would be many, many worlds full of very, very lost birds?

[@slevinchannel7589]

WOW: Have you seen the newest video of FTFE (Fight the Flat Earth)? It's amazing.

[@djelalhassan7631]

The Many-Worlds interpretation and Zeno is pure none sense there is only One-World and the Motion-Time is continues you cannot divide them.

[@elongatedmusk3132]

@@slevinchannel7589 I'm seriously 🤔

[@slevinchannel7589]

@@elongatedmusk3132 FTFe is a Channel? Was that not clear? And so is Holy Koolaid, just so you know.

[@elongatedmusk3132]

@@slevinchannel7589 I put curious or something & that emoji got hit. Anyways thnx I'll check em out

[@ScionVyse]

"Quantum Ouch" is my new favourite term.

but is it like wave or there is comes in packets of plank-ouches?

[@kennarajora6532]

I'd love to see that term included in movie technobabble.

[@TaohRihze]

Don't Blink!

[@medexamtoolsdotcom]

Followed by the sequel, Quantum Abort.

[@gbail9566]

If you pay attention you hear it coming after the Quantum Twang.

[@flensdude]

This reminds me of a poem attributed to Odin, chief god of all the Viking gods: _A fifth spell, I know―_ _if I see shot with ill intent_ _an arrow, travelling in a fight;_ _it's incapable of flying too quickly_ _for me to stop it in its path_ _as long as I keep my eyes on it._ (Odin, Hávamál. Rough translation.) _Þat kank fimta,_ _ef sék af fári skotinn_ _flęin í folki vaða,_ _flýgra svá stint,_ _at stǫðvigak,_ _ef hann sjónum of sék_ (Odin, Hávamál. Original poem.)

[@linorow2835]

Underated! Great poem!

[@Greywander87]

Interesting, I can actually recognize some words from the poem as probably meaning certain things, even though I don't speak Old Norse. Ef = if, sék = see (seek), skotinn = shoot, flýgra = fly, at stǫðvigak = to stop, sjónum = keep (sojourn). How accurate is this? Given that there are fewer words in the original poem, I'm assuming that each word carries more info that is normally spread across multiple English words. English did descend from this language, though it's gone through a lot of changes since then.

[@flensdude]

@@Greywander87 *On the relationship between Old Norse and English* Parts of the English language descends directly from Old Norse, but in fact all of the similarities in this poem are due to the fact that Old English and Old Norse were sister languages. That is, English and Old Norse have a common ancestral language (Proto-Germanic) from which these similar words ultimately are respectively derived from. Some of the words you recognise are correct. _ef_ is indeed related to English _if_ , although _ef_ was pronounced with a /v/ sound, i.e. /ev/. However _sék_ is a contraction of _sé ek_ , literally "see I" . Same with _stǫðvigak_ (< _stǫðviga ek_ ) and _kank_ (< _kann ek_ ), which literally mean "stop-not-I (it)" and "can-I". With the modern English word order and grammar you would instead say "I see", "I won't stop (it)" and "I know" in this context, but in Old Norse you had more liberty with regards to the word order and when to use pronouns like _it_ . Furthermore _sjónum_ means "with (my) sight" in this context, and is the dative form of the noun _sjón_ , meaning "sight" or "eyes". Just think about the past tense form _seen_ of the verb _to see_ , and you will see the relationship. Also note that _j_ in Old Norse is pronounced like /y/ in modern English. The English /j/ sound that you find in English words like _jet_ , _giant_ and _age_ is non-existent in Old Norse. Also, some of the verbs carry the short-lived negation ending _-a_ (sometimes _-at_ or simply _-t_ ), like in _flýgra_ < _flýgr-_*_a_* (literally "(it) flies-not"), same in _stǫðvigak_ < _stǫðvig-_*_a_*_ ek_ . (The latter expression here is incidentally a monster of a contraction _stǫðvigak_ < _stǫðva-ek-a-ek_ , quite literally "stop-I-not-I (it)". _stǫðva_ is thus the verb part of the word and means "to make stood", i.e. "to stop".) Other similar words are: _þat_ - "that" ( _þ_ is pronounced like _th_ ) _af_ - "of" (the Old Norse _of_ you see in the poem is actually related to English _ov-_ in _over_ ) _í_ - "in" ( _í_ was pronounced nasally in Old Norse, meaning it must have previously had an /n/ sound following it that was nasalised) _folki_ (dative of _folk_ ) - "folk/army" _svá_ - "so"

[@flensdude]

@@Greywander87 *On the word count* As you probably can tell from my previous comment, Old Norse could make use of contractions that make it seem like there are fewer words. They also had a grammatical case structure that Old English also had, but that modern English has lost. (You can tell from the endings _-i_ in _fári_ and _folki_ , and _-um_ in _sjónum_ .) This means that in Old Norse you could sometimes convey meaning without using prepositions by simply using specific grammatical cases, hence the word count would go down: _Gefk hónum vápn_ ("I am giving a weapon to him"); Old Norse uses three words here compared to seven in English. I also took the liberty to add words that aren't present in the original for clarification in my translation, since the Old Norse poem is composed in a special poetic language in which you have to conserve the amount of syllables in each line, thus the word count goes down. This is because the poem otherwise loses its rhythm in Old Norse. To keep the rhythm in English that has a higher word count, more words are naturally required.

[@growthisfreedomunitedearth7584]

I was thinking the same thing. The old ones understood quantum mechanix. I'm convinced celtic knots represent quantum systems.

[@robertstrawser1426]

Love the weeping angel reference. Just had a creepy thought. If the weeping angels were creatures governed by quantum mechanics that means they should also be able to quantum tunnel into your room at night, while you’re sleeping, even if you have the door locked. Pleasant dreams everyone… ;)

[@ericevans7741]

3:34 bless you, also this helped me understand what wave function collapse was better than anything else i've seen.

[@andrewgotlost]

I cant wait to watch this video 4 or 5 more times until I understand it.

[@TheMarcscod]

You don't understand quantum mechanics, you get used to it xD

[@mvmlego1212]

TBH, I thought this was much more understandable than plenty of their other videos, at least from the last couple of years. I don't think I'll ever truly understand the ones about the holographic principle.

[@victoroneil9735]

You actually can't understand it until you stop watching it. It's called the Quantum Dunno Effect.

[@silbermund4253]

Victor O'Neil 😂

[@AndreVanKammen]

@@victoroneil9735 At the exact moment you think you get the answer, your brain wil enter a superposition. Once you try to access the answer it will collapse and your back at the start.

[@BassNinja]

4:58 almost got me PBS

[@user-xv5wb6to7g]

Thank you for the photosensitivity warning, it’s deeply appreciated!

[@slevinchannel7589]

Try also: -Veritasium. -Its ok to be smart. -Neil Red. -Sci Man Dan. -Sci Show. -Practical Engineering. -Hbomberguy!!

[@thomasrichardson2905]

I know I will probably never get lucky enough to have my comment read, but here’s to hoping!!!! Matt, you and everyone else at SpaceTime are amazing. This show is my favorite part of the week because me and my daughter get to sit down and watch this show together, and now it has inspired her to pursue this field when she grows up. Keep up the good work and keep inspiring! Thanks.

[@ayehavgunne]

“So now you know why a quantum watched pot doesn’t boil. And it’s because you did watch. Spacetime.”

[@secularmonk5176]

First time I've seen an episode end without an elegant sentence ending in ... spacetime.

[@user-ut3ni6bu7b]

​ @Len Arends The sentence has 2 meanings: - You know it doesn't boil because you watched it - you know why it happened because you watched space time I think it's pretty elegant

[@DobromirManchev]

This was a cheat ending.

[@ayehavgunne]

Roadhouse

[@PrivateSi]

Spacetime loves sci-woo.... It's another Modern Mystery Cult media outlet.... It's named after 'MAGIC SPACE' for God''s sake, as an atheist... This quantises space and time and explains general relativity at the end, tying my coherent, balanced Standard Model fix together into a well integrated universe TOE model outline... It explains everything is semi-classical terms... it's basically a load of old balls that can collide, vibrate in unison as an electric subspace alternating current and flow in unison as a spinning, strong, magnetic direct current circuit... Simplicity beats complexity. There is much evidence for it. -- Subspace Charge Field: +ve charge cells (quanta, +1) held together by free-flowing -ve charge. Matter-energy field conserves momentum -- Matter-Energy: Matter is focused energy.. Energy is mobile matter.. Momentum conserves velocity.. Force changes velocity and/or direction -- Positron/Up Quark/Graviton (p+): Out of place, free cell warps the field and sends out AC field cell vibration 'blip' spheres at C + 6 spin loops -- Electron/Down Quark (e-): Hole left behind warps the field and sends out AC field cell vibration 'blip' spheres of opposite phase at C + 6 spin loops -- Neutrino/Dark Matter (n+-): Only exactly opposite phase p+ and e- annihilate (ie. pairs created together), else a neutrino forms -- Nucleons: Proton: P = pep.. Neutron: N = Pe = pep,e.. Beta-: e.. Beta+: B = p,n = p,pe.. Alpha: A = PNPN = PeP,PeP = (pep,e,pep)(pep,e,pep) -- Heavier Fermions: Larger holes and chunks of subspace field rapidly disintegrate to p+s, e-s, n+-s and/or annihilate to regular = empty field -- Electrostatic Force: Recoiling blip spheres propagate. Opposite direction + and - blips form a vibrating AC bond, same sign=phase repel -- Instant-Off Long Force: AC (longitudinally blipping) subspace 'flux tube' as thin as 1 cell wide. Each cell and its -ve charge move in contrary motion -- Spin: e-s and p+s pull in the 12 surrounding cells, or -ve charge that pulls cells, that then bounce out, forming 6 loops as a torus. Spins up/down -- Strong Force: Spin loops merge and form flowing DC circuits between e-s and p+s -- Mass: Sum of the lengths of all strong force bonds + near electric field. Neutrino has compact strong force bonds, Protons' are long as 2 p+s repel -- Magnetism: Some spin-aligned atoms' p+s and e-s' strong bonds join in a shorter straight path. Energy conservation results in external force circuits -- Weak Force: Geometric structural charge balance instability. Possibly neutrino hits statistically tipping the balance -- Photon: Charged particle(s) moving up and down (transmitter, atomic electron) form a radiating transverse wave blip pattern -- Double Slit: Laser light / particle centre's preceding, extended subspace distortion diffracts, interferes, forming wave guides observation destroys -- Dark Gravity: p+ traps 1 quantum of -ve charge so void cell size/gap grows (and matter's shrinks?) forming a macro -ve charge gradient -- Bang Expansion: Loss of -ve charge to the multiverse?.. Bang ejector velocity petered out, magnified in time by outward momentum conservation -- Gravity Wave: Longitudinal wave where the entire field in a large region is effected in unison for a duration -- Big Ping: A dark crystal universe collisions' intense gravity wave forms e- & p+ pairs from outside in at C. Many annihilate or form neutrinos -- Big Bang: Ping wave collides centrally? Field blast forms matter + a large hole (then Big/Dark Refill)? Fast -ve charge loss? Neutrino crystal exploded? -- Black Hole: Absorbs matter and energy. Neutrino crystal (with a core returning to empty field)? Large hole in the field traps anything entering? -- Frame Dragging: Entire sphere of subspace cells rotating around a point in unison -- Time: Cell to cell blips take a constant time. Gravity shrinks cells so light slows but locally measures C as circuits lengthen in space & time, adding mass -- Makes more sense than making up bosons to carry force and mass, quarks that don't solve the anti-matter and dark matter problem, anti-neutrinos, loads of fundamental fields, extra spatial and temporal dimensions etc, that ultimately don't tie relativity and quantum mechanics together properly or well... They should at least be honest and call their 'spatial dimensions' geometric/field dimensions or something.. Magic Space is not my cup of tea.

[@Felishamois]

I'm pretty sure this channel is getting into hypnotism guys, and I'm all for it

[@PrivateSi]

Yes, it is a NWO Scientific Dictatorship, Science Worship & Praise brainwashing channel populated by a load of dumbed-down, intentionally confused geek-trendies wanting more uber power to Nazti elites to burn our money on useless super-junk... You sheeple would be funny if you weren't such useful idiots!

[@Felishamois]

@@PrivateSi Well that was fun. I hope you make the distinction between the scientific method, argument of authority, and scientific theories because otherwise what you said didn't make any sense.

[@PrivateSi]

​ @Oeumuepo Stéphanois .. 'Science' with a capital S... The Scientific Method is the best testing method.. Systems Engineering is the best discipline for system engineering.. Arguments from authority and arguments from UBER-SCIENCE that only a handful really understand are functionally pretty much identical... I like to fight the confusion merchants out there, of the zealous, extremist variety... -- Scitards and Creatards that don't have a clue but pick an extremist side to praise and worship... This is fun, it's a semi-classical TOE outline that explains shed loads on half a side of A4 paper. It sticks to the evidence and the simple premise, with total conservation of energy. Time is left until last but ties general relativity at QM together nicely. -- Bottom-up Thought Experiment... Constraints: As few base forces and particles as possible to form a coherent, integrated 3D multi/universe model -- Subspace Charge Field: +ve charge cells (quanta, +1) held together by free-flowing -ve charge. Matter-energy field conserves momentum -- Matter-Energy: Matter is focused energy.. Energy is mobile matter.. Velocity is position change in time.. Force changes velocity and/or direction -- Positron/Up Quark/Graviton (p+): Out of place, free cell warps the field and sends out field cell vibration 'blip' spheres at C + 6 spin loops -- Electron/Down Quark (e-): Hole left behind warps the field and sends out field cell vibration 'blip' spheres at C + 6 spin loops -- Bion/Electron Neutrino/Dark Matter (n+-): Only exactly opposite phase p+ and e- annihilate (ie. pairs created together), else a Bion is formed -- Nucleons: Proton (P) = pep, Neutron (N) = Pe, Beta- = e, Beta+ (B) = p(n) = p(pe), Alpha (A) = PNPN = (PeP)(PeP) = (pep)(e)(pep)(pep)(e)(pep) -- Heavier Fermions: Larger holes and chunks of subspace field rapidly disintegrate to p+s, e-s, n+-s and/or annihilate to regular = empty field -- Electrostatic Force: Recoiling repulsive blip spheres propagate. Same phase blips repel, opposite form an attracting AC wave guide, recoil adds push -- Spin: e-s and p+s pull in the 12 surrounding cells, or -ve charge that pulls the cells, that then bounce out, forming 6 loops as a torus. Spins up/down -- Strong Force: Spin loops merge and form DC (flowing) circuits between e-s and p+s -- Mass: Length x number of strong force bonds + near electric field. Neutral bion has compact strong force circuits , Protons' are long as 2 p+s repel -- Magnetism: Some spin-aligned atoms' p+s and e-s' strong bonds join in a shorter straight path. Energy conservation results in external force circuits -- Long Instant Off Force: AC (longitudinally blipping) subspace 'flux tube' as thin as 1 cell wide. Each cell and its -ve charge move in contrary motion -- Weak Force: Geometric structural charge balance instability. Possibly statistical hits by bions tipping the balance -- Photon/Light: e- (or p+) moving alternately up and down (ie. transmitter or e- moving from a neutral ground state to charged higher level and back) -- Double Slit: Laser light / particle centre's preceding, extended subspace distortion diffracts, interferes, forming wave guides observation destroys -- Dark Gravity: p+ traps 1 quantum of -ve charge so void cell size/gap grows (and matter's shrinks?) forming a macro -ve charge gradient -- Bang Expansion: Loss of -ve charge to the multiverse?.. Bang ejector velocity petered out, magnified in time by outward momentum conservation -- Gravity Wave: Longitudinal wave where the entire field in a large region is effected in unison for a duration -- Big Ping: A dark crystal universe collisions's intense gravity wave forms e- & p+ pairs from outside in at C. Many annihilate or form bions -- Big Bang: Ping wave collides centrally / -ve charge lost to the multiverse / blasted cells and -ve charge form much matter and leave a truly empty hole? -- Black Hole: Absorbs matter and energy. Bion crystal? Truly empty hole in the field that rips matter to pieces, turning it into subspace field until full? -- Frame Dragging: Entire sphere of subspace cells rotating around a point in unison -- Time: Cell to cell blips take a constant time so light slows locally with gravity as cells shrink but always measures C locally as subspace circuits slow too-- -- Makes more sense than making up bosons to carry force and mass, quarks that don't solve the anti-matter and dark matter problem, anti-neutrinos, loads of fundamental fields, extra spatial and temporal dimensions etc, that ultimately don't tie relativity and quantum mechanics together properly or well... They should at least be honest and call their 'spatial dimensions' geometric/field dimensions or something.. Magic Space is not my cup of tea.

[@gibbsm]

@@Felishamois nothing this person will make any sense. they just cut/copy/paste mumbo jumbo, they said it themselves above.

[@jeffneptune2922]

This guy gets more info into a 15 minute clip than anyone I know. If you are a scientifically informed laymen, budding philosopher of science or "junior" scientist with a B.S. in chemistry, biology or physics, PBS Space Time is "the Bomb"!

[@PrajwalNayak-so5uv]

Sometimes I also have these kind of illogical doubts which seems to be logical, just like Paradoxes of Zeno, but I used to not think much about it as no one gives it importance saying that it is illogical and has an obvious answer. But now Zeno gave me MOTIVATION to think more and have these kind of confusing doubts, or to be precise, Paradoxes

[@acetate909]

@3:45, so that guy can observe quantum arrows and ancient aliens? What's a badass.

[@horus6153]

Ahaha...that's definitely Giorgio A. Tsoukalos from Ancient Aliens. Nice to see him branching out.

[@Jeppelelle]

Will there be a video about the new potential discovery at CERN about the decay of beauty quarks? Would be awesome 👍

[@diegofranco65]

That would be nice!

[@dankthorgaming5972]

I wasn’t going ‘thats what i was about to say’.your topic sounded cool :)

[@xyzpdq1122]

Probably something sooner but less imaginative on the Fermilab channel. Plus that has Don Lincoln’s great dad humor.

[@Jeppelelle]

@Questa Semplice Animazione weird comment, your comment is like correcting someone that says soccer instead of fotball even though they both are correct. So i choose to use the nicer name for that quark...

[@Jeppelelle]

@Questa Semplice Animazione its very common to use beauty & no one mistakes that for charm...also stop your fixation with claiming that correct names are incorrect, soccer is obviously not wrong. Anyways, this is the most pointless argument i’ve seen in a good while, i think you are a troll that just argues for the sake of arguing, which i’m not interested in since that belongs in kindergarten

[@Jop_pop]

As a mathematician, 1:08 is what a physicist would tell you. Very few mathematicians view time as made up of infinitesimal chunks - we'd talk about limits in our explanation. Each individual point in time has no duration, and thus no sense of velocity, and movement only appears in the relationships between nearby points in time (i.e. limiting behavior)

[@layneburton9172]

You did us dirty at the end there, playing on our psyches and making us think we're mad for predicting the video ending.

[@itarry4]

Isn't Zeno the same dude who also said that it should be impossible to ever catch a moving tortoise. Using a race between Achilles and the tortoise to illustrate the point.

[@carlosgaspar8447]

and the paradox does not hold for quantum particles because they (and time) are not infinitesimal.

[@drdca8263]

Yes, he had a number of similar paradoxes all leading to the conclusion that motion is impossible / is an illusion

[@itarry4]

@@drdca8263 yhea I thought it was him. Actually I leant about it in a Terry Pratchett novel where he joins 2 of the paradoxes together by having a philosopher called Xeno having a bet with another about the arrow hitting a Tortoise. So it crossed the Arrow one with the Achilles one, I then looked it up to find out what it really was.

[@nihad6727]

​@@carlosgaspar8447 Zeno: Then you should have no trouble measuring them rather easily and giving me their actual size?

[@carlosgaspar8447]

@@nihad6727 www.mathportal.org/calculators/sequences-calculators/geometric-sequences-calculator.php

[@vladdangel]

"observe" is such a cop out. If I'm blindfolded and my way of "observing" a baseball is by swinging a bat then yeah, some how when I observe a ball it travels away from me. This is the strange nature of observing baseballs in quantum mechanics.

[@doomerbloomer6160]

observation is just another word for interaction

[@dougmcguire2187]

I’ve said this before and I’ll say it again. You’re great dude. You explain this very well. I love you videos. You need a second channel reading bedtime stories. Your voice puts my son, and myself straight to sleep. You’re not boring. It’s just the tone. I’ve been fighting for 3 hours tonight with my son getting him to sleep. 7 minutes with your videos and he was snoring. You’re the best dude.

[@mannyourfriend]

This video was surprisingly understandable! Well done

[@nekomatafuyu]

I see. So video buffering is a quantum effect ;)

[@jorgepeterbarton]

Or inversely the matrix is buffering with quantum effects

[@techhelp1941]

Ha ha ha..... very well said. We can never see "true live cast".

[@Thejericko17]

Thank you for the Weeping Angel 🙌🏾

[@philteacheseverything5466]

Great video man. Makes perfect sense. Ya’ll keep it up! I love every video ya’ll make!

[@wenchinatrenchcoat8459]

Thank you PBS Space Time Team. I am challenged yet again and i love it!

[@chrisX1722]

Thanks. Now I know how the weeping angels work!

[@kokopelli314]

It would be more accurate and IMO helpful to replace the words "observation" and "measurement" with "interaction".

[@juzoli]

I do it routinely, as I always see people being confused about it... Every observation is an interaction, but not every interaction is observation. And wave function collapse happens at interaction, not at observation.

[@christopherbrent3759]

You'll never sound mystifying with an attitude like that!

[@davidabdollahi7906]

You guys been living under a rock or what. The whole concept of quantum physics is based on the changes in the states of sub atomic particles caused by "Human Consciousness". Quantum physicists try to have observations with zero interaction. This act of observation without interaction is what makes the results "Mystical" or otherwise it simply would be "scientifical".

[@MaakaSakuranbo]

Yeah, really not helping the impression people have that "observation" means "human looking at it" with those visuals either

[@juzoli]

@@davidabdollahi7906 That’s the exact misconception which comes from misusing these words. You misunderstood the whole concept. The whole point is that observation without interaction is IMPOSSIBLE, so we can NEVER observe a quantum particle without changing it. Consciousness is not even mentioned by physicists, it is coming from people who don’t understand.

[@BWYT452]

It's taken several years but he's finally talking about the biggest problem with Quantum Mechanics: "observation", "detection", and "measuring". These terms are flawed in QM. People speak and act like "simply observing" something changes it's state. That's untrue. The "observation" undertaken includes some type of particle bombardment and collision allowing for the measurement to be taken. That's like saying you can "observe" my car by sending other cars to collide with it, while ignoring the damage done to my car and the movement changes from the impacts. This is what the particle detector is doing in the infamous double slit experiment which claims to prove "observation" of the state change of an electron from a wave to a particle. The "measurement" they take is to perpendicularly bombard the path the electron will take with particles, then fire the electron through it. If they collide with the electron they can calculate based upon the deflection whether it went through the left slit or the right slit. They then conveniently ignore the fact that this impact also deflected the electron they were measuring. It's not mere "observation" that caused the "state change" but an actual, physical impact.

[@SP-ny1fk]

"And we can take this huge universe and put it inside a very tiny head: you fold it" - Rudolfo Llinas

[@kennarajora6532]

11:00, Is that dude laughing at the Schrodinger cat in the timeline where it dies?

[@chingamfong]

When the researchers classify constantly shining laser on an atom as "observation" Ballentine: "Wait that's illegal"

[@slevinchannel7589]

Try also: -Veritasium. -Its ok to be smart. -Neil Red. -Sci Man Dan. -Sci Show. -Practical Engineering. -Hbomberguy!!

[@Melgaer]

The Dr Who reference and how well it was executed distracted me so much that I had to pause the video to write this before coming back to the content. Bravo.

[@zerk317]

Wow. This video was great! Love this series!

[@fireburner81]

Got it. Weeping Angels are susceptible to the quantum xeno effect.

[@Vasharan]

They call it 'quantum locking' in the show, but same diff.

[@tubehellcat]

I was just about to say the same thing 😁👍

[@jorgepeterbarton]

@@Vasharan i must quantum lock my house because i can never remember whether i did, concluding i both did and didnt, but to a reasonable probability like 95%

[@SkatersHeaven]

i had to come watch this so my ramen would cook.

[@Ghost-hs6qq]

Lmao

[@PMA65537]

Well, perhaps the laws of physics cease to exist on your stove. -- Vinny Gambini

[@En_theo]

It's not really trolling. The Zeno paradox may have been "solved" mathematically but physically speaking, we still have quantum fields and still don't know what time is.

[@Cronos804]

Im a mathematician and for zenos paradox the argument i know to solve it goes as follows : Some properties just cant be checked by distributing a check onto subsystems. They depend on the whole system and not just its parts. The main example is often given in the form of the pigeonhole principle. In order to fit 5 Pigeons into 4 holes there must be at least one hole with more than one pigeon. In other words : Not every pigeon can have its own hole. You can check this by comparing the number of holes vs the number of pigeons easily. What you cant do is just look at each hole, find that one of them is somehow 'too small' and than conclude that not every pigeon can have its own hole because of this. None of the holes is special - there just arent enough. Same for the arrow. Movement is a property of the object respective to a time interval. If you only look at individual moments, you might draw the wrong conclusion.

[@NovaRuner]

I think Zeno had another paradox to his name. I might be off on some details but the one I have heard of goes like this: I try to walk from point A to point B, it takes me some interval of time to go half way, it takes half of that interval to reach the 3 quarter point, and it takes an infinite set of smaller and smaller intervals to reach an infinite set of smaller and smaller fractions of the remaining distance and so I can never actually reach point B Awesome videos keep up the good work and maybe make the above paradox into quantum weirdness too.

[@jamespiar]

Wow, I actually took a course in mathematics on Wondrium, formerly the great courses, by Professor Bruce Edwards where he explained this version of Zeno's paradox . You are absolutely correct. 🏆

[@FabioLeprechaun]

"But Zeno, Greek philosopher famous for his metaphysical trolling" I will use this in class for now on.

[@reldahr01]

They proved this in "The Outer Wilds". Alternately you can take a picture of the arrow and then blink as much as you want.

[@slevinchannel7589]

Try also: -Veritasium. -Its ok to be smart. -Neil Red. -Sci Man Dan. -Sci Show. -Practical Engineering. -Hbomberguy!!

[@amaliaantonopoulou2644]

The amazing thing about this channel is that every time I start watching a video, I'm sure that I don't have many possibilities to understand a lot, but at the end of the video I think that I have understood everything!!! Haha!Magic

[@slevinchannel7589]

Try also: -Veritasium. -Its ok to be smart. -Neil Red. -Sci Man Dan. -Sci Show. -Practical Engineering. -Hbomberguy!!

[@commandershepard6189]

On a statement in your last episode... As a Engineer, I like to look at time as the totality of all velocities and space as the volume to which those velocities move through. Time as the function and space as the junction. I theorize: all of the prior and present fluid mechanics of a given collapsed star (inversed) directly relate to our expansion in this universe. This star would exist in an timeline closely related to the total probabilities of this universe. Einstein's Rosen bridge is a link beyond the plank scale in relation to probabilities to which gives rise to coherency. The decoherent probabilities are only there because our inability to see beyond our own timeline. What is and has been will lead to the now and forever more. One could only know if it has already been.

[@menso541]

Quantum particles: I can't get anything done when you sit there staring at me..

[@Games_and_Music]

They're insecure, stagefreight.

[@bigcat5348]

If a quantum arrow can only exist at the start or the end of its journey, then shouldn't such a projectile be completely harmless? Projectiles derive their lethal power from the kinetic energy created by movement from point A to point B...

[@TiagoH1710]

XD

[@sinteleon]

Maybe a perfectly harmless arrow lodged in you, since there probably is a post impact frame.

[@zyzhang1130]

I’m impressed that weeping angle has solids science to back it up

[@heavylight9725]

Excellent explanation

[@Daavlot]

Oh no! Even Space Time has jumpscares now XD

[@woawjack]

the moment you said "your call freeze a quantum state by measuring it continuously" my exact thought was "I would say interacting rather than measuring" and exactly then you mentioned leslie ballebtine saying exactly this! I felt really proud of my reasoning after 5 years of pbs spacetime! (wow I am technically well into my masters in spacetime! without ever popping a calculator will you look at that)

[@user-wk7iq1yf4w]

Excellent episode!

[@darismelabishai1027]

Fantastic production, as always... despite the missed opportunity of taking a quantum arrow to the knee 12:01

[@michaelupdike-bz6rg]

I was reading "How To Teach Quantum Physics To Your Dog" and never understood this. This makes everything click.

[@taufiqutomo]

@JohnR2319881222 Imagine hundreds of years later, our descendants might use that quote to describe how mysterious quantum mechanics is to their ancestors, just to highlight how much humanity's understanding of physics have advanced.

[@jeroendijstelblom8614]

Masterpiece 👌🏻👌🏻

[@rigeus]

This just made one of the best Dr. Who episodes ever, even better! Thanks! Not blinking, not blinking, not bl

[@iuribachnivsky3022]

Those physics 'staches are gorgeous!!!

[@ravenlord4]

I always thought that "instantaneous velocity" was just an theoretical artifact of calculus, seeing how in the real world even the smallest distance over time component is subjected to the limits of planck length and planck time.

[@Rich-hy2ey]

Funny there is no impact on the object by the start-stop action of the Planck length travel.

[@slevinchannel7589]

@Parker Sullins Try also: -Veritasium. -Its ok to be smart. -Neil Red. -Sci Man Dan. -Sci Show. -Practical Engineering. -Hbomberguy!!

[@djelalhassan7631]

@Parker Sullins Yes true, the Motion-Time is continues you cannot divide them.

[@wormalism]

I thought Planck length was the smallest size a particle could be, but that particle is supposed to be able to move through infinitely divisible space?

[@ravenlord4]

@@wormalism The planck length covers both size and distance

[@lrwerewolf]

"That which holds the image of an angel becomes itself an angel."

[@ChattahoocheeRiverRat]

So my Roku box, computer and TV are now all angels?

[@kylebowles9820]

Awesome, well explained! I really think I understand the controversy!

[@DGCMWC]

I love the look Matt gave the camera at the end of the video when he deadpanned "space-time."

[@Daniel-Strain]

Sounds like Zeno was just describing what I learned on PBS Space Time is called a "block universe" model.

[@mr.aleximer]

I hope ill finally understand this video after many years of just observing pretending im here for educational purposes...

[@LuanMower55]

Same, been here for years, don't understand even 10% of what he says but i like his voice...

[@Haannibal777]

I am sure in some alternate reality, you do understand. This is called “Many Worlds Interpretation”.

[@ggiorgib]

The fact that I can't argue about anything here or hold any opinions due to my nonexistent knowledge in this field is very calming and feels like magic.

[@Eversing93]

@@ggiorgib Also a very good way to let the universe humble you a fair bit every once in a while.

[@DrDeuteron]

there are plenty of working physics PhD who have only 'wtf' to say about the (anti)quantum Zeno effect.

[@jacquesstoop2587]

Hope you guys one day get round to making an episode on high frequency relic gravitational waves and measuring them using the Li Baker effect. Would be awesome.

[@ZefulStarson]

It's really nice that Space Time did an episode on the science of D&D.

[@patrick-kees8962]

Arrows that don't move as long as you stare at them. This sounds like the weeping angels, as long as you don't look they stay still but stop observing them and they appear next to you.

[@corinnemuir1542]

Is Dr Who big where you live?

[@Seth-Halo]

Iirc the Weeping Angel's had something to do with quantum mechanics. Ya they could Quantum-lock. Also fun how they used Weeping angel reference in video

[@Bassotronics]

Súper Mario Ghosts. (Boos / Teresa) As long as you’re looking at them they don’t move.

[@Skubasteph]

or the ghost from super mario

[@Bassotronics]

@ *steve* Thanks for confirming what I said above.

[@fffUUUUUU]

"Because you watched... spacetime" lol 😂

[@jcinaz]

Nice touch @5:01 with "Don't Blink" from Dr. Who.

[@misseimear]

you unlocked a deep, deep fear within me with that weeping angel jumpscare

[@__rikaisuru]

“ Zeno, Greek philosopher famous for his _metaphysical trolling_ ”

[@vorname1485]

He trolled once an archer who tried to shoot an arrow at him.

[@paulperkins1615]

I take that as a hint that this whole episode is an example of Quantum Trolling.

[@Camelotsmoon]

So is that why things you want never happen (because you always pay attention to them), and things you don't want to happen always do (because you try to ignore them)?

[@michaelthompson6624]

Soo, super cool. Quantum thinking, distinct from real quantum stuff, whatever that turns out to be, could be super useful. I love these pbs space-time pulsations.

[@doobie_mouse2083]

Whats funny is I was already thinking Dr. Who tought me this trick years ago and then bam! Weeping Angel. You guys are the best. Stay awesome and thank you for keeping my mind curious.

[@saranshkumar1744]

We are slowly starting to discover that we live in a simulation.

[@achronicblunt]

I've always wondered if the inability to measure location and momentum at the same time is that location requires a definite point in space to be measured, while velocity requires measuring two points, and the time that passed between them, and so it is inherently impossible to measure both at once when you are working with objects that exist at the quantum level, which are so small that they can't even be said to occupy more than one location at a time, perhaps, at all. In a sense, you are measuring either location once (i.e. location), or you are measuring location twice (i.e. velocity). Am I missing something? How could velocity even conceivably be measured with a particle only occupying a single location? Without linear distance there is nothing for time to measure. This would propose a solution to Zeno's paradox as well: Particles MUST occupy definite locations in space. At any given moment, their location can be measured. So what if particles do not exist IN a location in space? What if particles ARE a location in space? Then there is no need to ask where they are between two spaces. They "are" not. Because the energy didn't travel between two separate locations: it was in one location, then it was in the next. Zeno's arrow doesn't travel. It teleports. Paradox resolved.

[@djelalhassan7631]

Yes true, the Motion-Time is continues you cannot divide them

[@stevenjones8575]

I love you, SpaceTime. You're such a fantastic channel. The "Science" cheerleading and the vaunting of scientists above common plebs is one of the (very forgivable) flaws of this channel. I'm not even sure what, exactly, you're cheerleading. The scientific community? Scientific community's consensus? The scientific method? Plenty of non-scientists use reasoning, form hypotheses, test their ideas, check and correct each other, enjoy learning new things and making new discoveries, etc. The scientific community has accomplished many things with the many resources available to it. And I very much love learning the things the scientific community has learned and is sharing. And that community is full of people, people who like to be right and very much dislike being wrong, just like any other group of people. Hailing "Science" as the Best Thing Ever is akin to looking at the court system and judicial community, calling it "Justice" and then hailing said Justice as the best thing ever because they hold principles of truth and fact finding and evidence (which they also often fail at). I admire the principles that the scientific community holds dear. And what should be vaunted--rather than "Science"--are those principles: Logical reasoning, testing, acceptance of one's own errors, evidence gathering, peer review, etc. Because none of these are exclusive to the scientific community. And some communities desperately need to embrace these principles without having to join "Science." Again, I love you all there at SpaceTime. You've greatly enriched my life. Thanks.

[@hawsroy]

this is wonderfully interesting. however, i am interested: what may happen if we look to speed up the collapse of the wave function/what use may it have? love the videos :)

[@Tacticslion]

“As it turns out, if you punch an archer really hard and then put him in a box full of concrete, he can’t shoot you with an arrow.”

[@viveklakshman2897]

But then you have to really be observant while punching, because if you miss, you can't freeze the initial state and the wave function collapses to the final state of you getting hit! So, observation is must! Both while just observing or even punching.

[@Tacticslion]

@@viveklakshman2897 Ah! Now you've discovered the violence inherent in the system! (The punching and box-putting *is* the observing.)

[@mimzim7141]

Then isnt laser stimulated emission an anti-zeno effect?

[@danieljensen2626]

No, for stimulated emission the electrons have to be in the right state to begin with.

[@mimzim7141]

@@danieljensen2626 what is the difference? You are forcing the transition between two states by interaction with a photon. You can see the original situation as a superposition of the highest and lowest state with a big weight on the highest. The photon transfers the weight on the lowest effectively forcing the transition.

[@adee4151]

wow, last time I've seen a Great Courses PLUS ad, is five years ago.

[@locdogg12]

Your puns get more and more elaborate with every new episode :D

[@tjitsekoster9379]

I love they cleverly manage, through careful writing, to end all episodes with "space time".

[@ldeadpirate9432]

So, iNeed to come up with something that can observe or decohere my entire physical self on a quantum lvl in order to achieve immortality thru stasis?

[@Pyxis10]

Whats the difference between that and being dead? You aren't aware either way.

[@ldeadpirate9432]

@@Pyxis10 Because iWould be able to use a simple timing system to stop observing my quantum processes at a certain time or after a certain amount of time. Or if it ever stopped working or had power shut off, iWould hope to return to the mobility of the unobserved, XD

[@RCaIabraro]

I did watch Space Time. This was a particularly good episode. Cutting edge science and philosophy of science

[@shivaray2588]

omg...that is insane.thanks for cool explanation

[@SenorQuichotte]

i can stare at a pot until it boils, i can have the patience of eons.

[@Games_and_Music]

I kinda expected a reference to Kylo Ren in Star Wars, as that was a pretty cool scene where he froze the blaster shot. But maybe it's a contract thing.

[@blahblahgdp]

If we could manipulate quantum mechanics I think the force could become very real

[@clarke762]

@@blahblahgdp how so?

[@-Blue-_]

@@blahblahgdp can you plz tell in detail

[@pokeman123451]

@@-Blue-_ he has the full proof, but its too long to write here. its simple really, trust him on this one 🥴

[@-Blue-_]

@@pokeman123451 really bro ?? I am serious brother 😥😥😥

[@chadbaptiste4227]

Well done!

[@Muhd21]

I read the title as “Can you observe a quantum system by observing it?”

[@gibbsm]

🤯

[@pasqualecirone9755]

Reminds me of the Weeping Angels from Dr Who!!! Don't blink!

[@object_name]

But you did notice, that they included an image of exactly that the first time he said "don't blink"?

[@pasqualecirone9755]

@@object_name oh, no. I usually listen to these despite the visuals can be helpful.

[@wyatteichholz3139]

"don't blink" So basically we're talking about a Dr Who episode at this point.

[@fariesz6786]

spacetimey-whimey stuff

[@markfoster1520]

Wibbily-wobbily

[@project.eutopia]

If the rate the arrow transitions to the final state is linear, say taking 1 sec to completely transition, then no matter how rapidly you observe the arrow the expected time it will take to transition to the final state is 1 sec. If you observe every time interval t, then the chance of transitioning is t and the chance to stay put is 1-t. The expected time is then SUM nt * t(1-t)^(n-1), which equals 1. So whether it is possible to freeze such an arrow intimately depends on the rate the weights in the superposition change over time.

[@CroatInAKilt]

I was just recovering from Skull Cat when you went and hit me with the Weeping Angel