Quantum 101 Episode 6: Quantum Probability Explained
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- Опубліковано 7 сер 2023
- When Albert Einstein famously said "God does not play dice with the universe" he wasn't objecting to the idea that randomness exists in our everyday lives.
What he didn't like was the idea that randomness is so essential to the laws of physics, that even with the most precise measurements and carefully controlled experiments there would always be some level at which the outcome is effectively an educated guess. He believed there was another option.
This video discusses how probability is determined in quantum mechanics. Let's play some dice with the universe and talk about it.
Join Katie Mack, Perimeter Institute’s Hawking Chair in Cosmology and Science Communication, over 10 short forays into the weird, wonderful world of quantum science. Episodes are published weekly, subscribe to our channel so you don’t miss an update.
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The Quantum 101 series is very well done. It takes the fundamental aspects of Quantum theory and explains it in beautifully simple terms. It also mentions the known and unknown details the theory. Keep up the good work.
This material could be very useful in high school physics class to help explain quantum theory.
I've always wondered by Feynman required ALL possible paths to be represented in his representation... and one line in this video, that in QM ALL possible states are happening at the same time and so must be factored into the probability analysis made me go "oh... of course... that makes perfect sense". Weirdly I knew all the parts but this was the first time it came together.
It makes me rather proud that the Perimeter Institute, creating these excellent videos and doing exceptional physics, is Canadian.
Einsteins comment about “God does not play dice with the Universe” is greatly mis-understood by most people. It’s important to define the “God” Einstein was referring to as the God of Spinoza, who is more of a philosophical entity than a “God” in the modern Western sense. To Einstein, “God” is simply the laws of nature. And when Einstein said this God does not play dice, he was referring to the essence of quantum indeterminacy, regarding certain quantum effects such as radioactive emission. Essentially he was objecting to the Shrodinger’s Cat thought experiment and the like.
Einstein believed in actual God as well. In this comment he was actually referring to both at thd same time.
Einstein wasn't an atheist and his later writings and dialogues make that clear.
Excellent as always. Thanks especially for your explanation of the “wave function”
Einstein was so smart he often outsmarted himself. Poor guy. He won the Noble prize for something that essentially started the whole study of Quantum Physics. And yet for the longest time he refused to accept it. Although, he did come around in the end.
i mean, i still think he's fundamentally right. a simpler/better explanation for the result of the bell experiments is that the universe is deterministic, like einstein was saying. information doesn't travel faster than light. it's just that the "random" polarizations on each side were already known ahead of time.
Your videos are excellent Katie, it makes me wish UA-cam existed when I was a Physics student ;)
This is something very close to the philosophy of our perspective makes our world.. what we observe becomes our reality
to be exact, a pair of entangled particles is a pair of particles that, despite the uncertainty principle, we can guarantee with total certainty that they interacted at some point or shared the same origin, their properties being correlated, there is no distance communication as such in entanglement, therefore does not violate any law. In fact, if it weren't for entanglement and quantum decoherence, quantum would be nothing more than indeterminacy, those mechanisms bring order to the matter.
Great quantum primer!
I really enjoyed your well produced video and concise expectations.
As always for best results sample the multiverse with care. 5:33
Great video. Neat to ponder on just how perplexing the quantum world has been for physicists and where physicists are pointing to heading forward. Playing with a one of those dice sounds like fun. 🤣
Very good. Thanks.
How can I delete this video on the playlist
The funny thing about particle collisions is the uncertainty.
It's as if planes of uncertainties emanate around some center of pure uncertainty.
From this viewpoint, the only thing we're ever really certain of is uncertainty.
I fear this inverted epistemology may be inherent to a forward looking perspective in time.
Retroactively we can say for certain that something happened, it's when you start asking questions about what happens next that all the problems with uncertainties appear.
Isn't energy itself a predictive measurement? In the sense that given some set of causes, we have grounds to assume a potential set of effects.
Could the wave function Ψ² represent the forward passage of time itself within an individual reference frame? Light photon ∆E=hf energy is continuously transforming potential energy into the kinetic Eₖ=½mv² energy of matter, in the form of electrons. Kinetic energy is the energy of what is actually ‘happening’ the energy of motion. The dynamic geometry of this process forms Heisenberg’s Uncertainty Principle ∆×∆pᵪ≥h/4π. That is this theory represents a probabilistic future continuously unfolding relative to the electron probability cloud of the atoms and the wavelength of the light.
It’s frustrating to be interested and open to physics yet have so little comprehension. This shouldn’t keep my attention, they might as well be speaking Latin. But here I am. I think that if even one piece of information made sense to me, my world view may be completely different. In a positive way. I just can’t wrap my brain cells around this stuff. Grateful for those of you that can, and do.
My view is that the collapse is caused by souls that have a stratified structure in many extradimensional realms. This is why people can effortlessly every day solve so many open-ended problems where unforeseen events can happen, like driven a car from A to B, that current AI designed no to be affected by quantum noise, is taking a long time to become better at. Also, why DNA can evolve by intelligent design. When the collapse is caused by the soul to entangles particles it may send information faster than light and cause timeline paradoxes if not for the creation of parallel universes, that can't talk to each other. In my current view.
The brain may be an antenna for quantum collapse information because of the high field strengths over small distances. Like the million volts/meter over the cell membranes. This view could also be tested by searching for meaningful patterns in quantum events.
If a particle's position and velocity cannot BOTH be determined, does that mean it DOESN'T have both a position and velocity? Or that it does and we just can't determine both? Which is it?
Neither, What happens is that more certainty in position decreases certainty in momentum and conversely. But there is no such a fact,, in QM of both concepts existing independent of measurement.
It has a probability field of positions and momenta that are related. So the act of measuring one changes the other. You can measure either one to 100% certainty, but that makes the other 100% uncertain. What Heisenberg's Equation states is that the uncertainly of the two together can never be less than a set constant (bar-h / 2).
Think of it this way (and this is an analogy, QM doesn't work this way but it gets the idea across), you don't know the position or the momentum of a particle. You want to measure both - but to measure position, you have to stop the particle so it HAS a definite position. That means you cannot know what momentum it had just before stopping because now it's stopped - it could have had any momentum in any direction. Conversely, if I want to measure momentum, the object MUST be moving (momentum is mass times velocity and velocity is change in position over time), and so has no specific location.
To be precise and accurate, it’s a particle’s position and MOMENTUM that cannot both be measured precisely at the same time. Subtle, but important difference.
The uncertainty principle tells you that certain pairs of magnitudes commute or do not commute, it means that the order in which you measure such magnitudes can affect the result, for example, it does not matter to measure the speed first and then the position of a plane since that does not change the result. But in a quantum particle it is important to define if you measure first one and then another, measuring one magnitude will destroy the information of the other magnitude, think of the quantum as the most delicate objects in the universe.
The more i learn about quantum mechanics the clear it is that it is only an approximation. You cannot have a probalistic wave function result in deterministic behaviour without some form of mechnism to convert the two, probailoty is useful as a tool to describe things with unknown mechnisms, this feela like the case with quantum mechnics.
The "deterministic behavior" is only displayed by the ensemble average. Since an ensemble has an infinite number of members, it can not exist in reality. The problem that you are imagining does therefor not even exist. Sometimes "idealizations" (like the real numbers) have very nice properties that the underlying actually realized objects (like fractions) do not have. If you want a trivial probabilistic example for this: the average outcome of dice is 3.5. Dice do not have a side that shows 3.5. Does that invalidate dice and/or probability theory? Of course not.
@lepidoptera9337 I think your missing the point. I'm nit saying wave functions are "wrong" so much as it is not actually representing what is happening. You dice analogy is actually the point I'm making. There is no dice roll of 3.5 but using probabalilty gives us that number, it can still be predicative, just not representing of the actual reality of the event. The wave function is a probabilistic "estimation" of the net events experianced by the particle. It is still useful, but the particles in question is not 1/5 here or 2/77th there. It has a definite position in space, the issues we run into with quantum mechnivs are at least partially the result of probability trying to be applied to individual objects, resulting in nonsensical numbers that in agrigate appear to show reality.
@@davidhobbs5679 Wave functions are representing what is happening on average. The outcome of a single quantum measurement is not predictable. The wave function is therefor NOT a physical property of the single system. It's an abstract description of an abstract ensemble. If your point is that this is frequently misrepresented in the literate and in the way we teach quantum mechanics, then I will wholeheartedly agree with you.
I would, however, suggest that you re-think that whole "particle with position" line of thought. There are no particles in nature. A measurement in quantum mechanics is the irreversible transfer of a small amount of energy, momentum, angular momentum and charges between a free quantum field and a system we call "the detector". Because of spacetime symmetries these properties are locally conserved, so they might look like they are somehow attached to a material carrier we call "particle" but that's as much a mirage as the phlogiston was as a carrier of heat energy. Humans have a tendency to objectify conserved properties. We don't just do it in physics, we do it in every day life with things like "money". Money is an exchange function, it's NOT the bank notes and coins in our pockets. In the same way energy, momentum etc. are just exchanged properties. They are NOT incarnated in some mythological little objects that nobody has ever seen.
There are no particles and for that reason alone particles can not possibly carry a quantum state. Not even a single copy of a quantum system carries a state. Only the ensemble of infinite copies of that system carries something like an identifiable state. This follows more or less trivially from the structure of the theory, we just don't teach this properly.
"each die is still in a superposition of every possible state until we measure it". i've never seen any evidence presented for this. it has an exact state, but you just don't know it. the "counter" to this is like bell's experiments, but those could be better explained by a deterministic universe.
Does this mean if I never look at the dice, I will always get full score in Yatzy?
Jokes aside, I love these videos!
So this make gipsie tarot reader more like quantum readers if they use a 52 cards decks separated in 4 kinds to represent the seasons darkand green eyed persons sparrow and spade and grey and blue eyed persons on hearts and clubs forcasts?
why quantum entanglement slow down its speed if we are vigilante about it's speed
Nothing to do with observing, everything to do with measuring.
I take issue with the explanations of quantum physics. I think there are still too many unaccounted for variables to make accurate assumptions
💙
Randomness do not exists, it looks due to possibilities we can not imagine.... what exists is at every point there are lots of possibilities , which every you choose based will present based on your current one other possibilities...so that means at point A you have three choice 1 2 3, you can choose A +1 ( k , l , m), A+2( x,o,p), A+3(s,u,r) . after that you will have only A +1 ( k , l , m) means A+1+k, A+1+l, A+1+m ....that means every possibility depends upon your prior choice and one specific sequence will always same path no randomness. thats why ..if you ddo bad karma ...you go hell...do goof karma go heaven. Soul is a substance in ore condition, become innert is goal.
The quantum collapse that everybody is talking about is still ego-based. Just because you perceive a small part of something doesn't mean the rest of it doesn't exist. That's like saying when you see a whole forest and approach it in your car when you get close to it it collapses to the view just around the road which isn't true. The observer doesn't have any power or control but rather sees a small portion and considers it the entirety.
Di? Dice
Quantum mechanics
I know I know nothing
Are we near to prove GOD in Lab?
*_Stranger Things: Reality Edition_*
📍3:15
God has the red die, and he’s the only one who has one
too much music, to much camera movements, to much bombastic statements and hand movements...and so little of substance
then go read a book
@@cletusclucker I guess, you know where you should go? Or should I make it explicit?
Oversimplified and incorrect. What about Bell?
What about Bell? Bell is intellectual nonsense. Read Bell's paper. Do you know what he says in the conclusion? He admits that his own non-relativistic analysis is false and that the only way to correctly understand the phenomenon is using special relativity.
That is not what he wrote
cds.cern.ch/record/111654/files/vol1p195-200_001.pdf
You can read what Bell wrote at that link.
@@lepidoptera9337
cds.cern.ch/record/111654/files/vol1p195-200_001.pdf@@lepidoptera9337
That is not what Bell wrote at all. You can read it for yourself.
I don’t believe in atheism… sorry