Sean Carroll: What is the Wave Function?

Once it reaches 20,000 subscribers, I'll start posting the clips there instead.
(more links below)

For now, new full episodes are released once or twice a week and a few new clips or a new non-podcast video is released on all other days.

Podcast full episodes playlist:

Podcasts clips playlist:

Podcast website:

Podcast on Apple Podcasts (iTunes):

Podcast on Spotify:

Podcast RSS:

Note: I select clips with insights from these much longer conversation with the hope of helping make these ideas more accessible and discoverable. Ultimately, this podcast is a small side hobby for me with the goal of sharing and discussing ideas. I did a poll and 92% of people either liked or loved the posting of daily clips, 2% were indifferent, and 6% hated it, some suggesting that I post them on a separate YouTube channel. I hear the 6% and partially agree, so am torn about the whole thing. I tried creating a separate clips channel but the YouTube algorithm makes it very difficult for that channel to grow. So for a little while, I'll keep posting clips on this channel. I ask for your patience and to see these clips as supporting the dissemination of knowledge contained in nuanced discussion. If you enjoy it, consider subscribing, sharing, and commenting.

Sean Carroll is a theoretical physicist at Caltech and Santa Fe Institute specializing in quantum mechanics, arrow of time, cosmology, and gravitation. He is the author of several popular books and is a host of a great podcast called Mindscape.

Subscribe to this YouTube channel or connect on:

[lexfridman]

Once it reaches 20, 000 subscribers, I'll start posting the clips there instead.
(more links below)

For now, new full episodes are released once or twice a week and a few new clips or a new non-podcast video is released on all other days.

Podcast full episodes playlist:

Podcasts clips playlist:

Podcast website:

Podcast on Apple Podcasts (iTunes):

Podcast on Spotify:

Podcast RSS:

Note: I select clips with insights from these much longer conversation with the hope of helping make these ideas more accessible and discoverable. Ultimately, this podcast is a small side hobby for me with the goal of sharing and discussing ideas. I did a poll and 92% of people either liked or loved the posting of daily clips, 2% were indifferent, and 6% hated it, some suggesting that I post them on a separate YouTube channel. I hear the 6% and partially agree, so am torn about the whole thing. I tried creating a separate clips channel but the YouTube algorithm makes it very difficult for that channel to grow. So for a little while, I'll keep posting clips on this channel. I ask for your patience and to see these clips as supporting the dissemination of knowledge contained in nuanced discussion. If you enjoy it, consider subscribing, sharing, and commenting.

Sean Carroll is a theoretical physicist at Caltech and Santa Fe Institute specializing in quantum mechanics, arrow of time, cosmology, and gravitation. He is the author of several popular books and is a host of a great podcast called Mindscape.

Subscribe to this YouTube channel or connect on:

[Remo]

This concept sounds so simple, yet I can’t wrap my head around it. It’s the same when I try to picture an object with more than three dimensions.

[tornadospin]

This is one of the best descriptions of wave-particle duality I have ever heard

[llamawizard]

how did he go from what I thought was a wave function for an atom to a single wave function for the entire universe?!? 😭

[DCnorth]

You let the last sentence be “and there is only one wave function for the entire universe at once”

Why would you do this to us

[dn-liww]

he’s like robert california but he’s actually saying things

[joshuabarlow]

From a mathematical standpoint what is your opinion on the fact The QM wave-function can act as the physical time/space/matter matrix of a conscious choice function that is the combined function of all choices, and which would return exactly the wave-function when any choice was relevant(a set of measurement values for operated wave functions). Why when conscious choice is obvious, and the mathematics of conscious choice are identical to QM ignoring the hidden variable choice function, why do physicists not simple assume choice is/are the causal force creating the wave-function - as so many deny free-will, which mathematically can be defined and tested and the result of which is literally the Wave-function?

[q-sumukhms]

If electron were to be a wave why wud it not dampen is really making it maintain constant amplitude through out time??

[XorAlex]

Очень интересно, но все равно ничего не понятно. What does it mean there is only one wave function for the whole universe?

[CoreyChambersLA]

Isn't that also called the single electron theory?

[Langkowski]

So two electrons that share the same wave function is just a single wave that split into two electrons when the wave cease to exist?

[JamesWattMusic]

Is there any way to verify the wave function with experiment? Perhaps measure position of Hydrogen molecule at many locations and recreate the theoretical probability distribution? I can’t find anything like this. Thanks.

[rams]

He said in a different video that an electron in the table could collapse and the table(maybe universe) collapses into nothing. and if all electrons are attached by the same wave, does that the entire universe could collapse into nothing at any time? Also if the galaxy is expanding faster than the speed of light, would a collapse in our galaxy effect anything that had moved away faster than the speed of light? cra

[gogll]

It's a shame people's didn't pay attention to learning calculus and basic function theory in high school, then there wouldn't be so much confusion on what we know for certain with QM.

Shrödingers equation is a class of partial differential wave equations.

The function we solve for is a function taking values from a state space (so this is one parameter for time and then one or more parameters for the position of one or more particles) to a complex value.

If you have a region of the state space and integrate the square of the solved wave function then you get the probability that your observation is in that state space.


That's what experiments show. Nothing else nothing more. Copenhagen and many worlds are just philosophical ways of trying to infer "underlying truths" of the universe from this mathematical model.

[ValidatingUsername]

Imagine being able to use FFT to cut out the periodicity of primes and twin primes for a proof by contradiction

[hikmatullahpakhtoon]

Well than What is the difference between wave function and de broglie wave? It seems from your explanation that both are the same thing but i don't think so.

[elumarsouza]

Unfortunately we were not educated to understand things, we were educated to consume things. A few manage to excel not thanks to school, but in spite of it.

[wulphstein]

String theory doesn't seem to be a contender for a quantum gravity theory because a quantum gravity theory has to answer the question: what is spacetime made of? Twistor theory is the closest to answering "what is spacetime made of". But it falls short because "twisters" cannot be experimentally detected or isolated. It is the same situation with Loop Quantum Gravity. Those loops cannot be isolated either. But it is worse than that. Neither of those theories are compatible with big bang expansion. You would expect that, whatever spacetime is made of, that such "atoms of spacetime" require an "expansion" parameter because the big bang "expanded" from a point.

Someone needs to come up with a quantum gravity theory that answers the question: what is spacetime made of/what are the atoms of spacetime. I would suggest calling it, the Expanding Graviton. The Expanding Graviton has three primary characteristics. 1) Expanding Gravitons are the carriers of the physics constants. 2) Expanding Gravitons are equivalent to wave functions; thus wave functions and their operators are real things; and now they are a manifestation of gravitons. 3) Expanding gravitons expand spherically, at the speed of light, with radius r = ct. Where in physics have we seen something that looks like an expanding sphere? Two places. First, the derivation of time dilation. Second, two slit interference pattern.

A proper quantum gravity theory should have an experiment associated with it. I would suggest that quantum entanglements between photons, are (Captured) Gravitons; it's not really an Expanding Graviton if it is captured between two photons whose positions can be controlled with optical fiber, lenses, mirrors, etc. I would also comment that it takes a tiny amount of energy to capture a graviton; if you add up all of the gravitons in the universe, then that number of gravitons multiplied by the capture energy of a graviton should equal DARK ENERGY. More importantly, if a quantum entanglement IS a graviton, then we can do experiments on it.

Someone needs to create a quantum gravity theory that looks like the outline above.

[KrishnaChaitanya]

If there's a single wave function for the entire universe, wouldn't a "collapse" affect the entire universe at once?

[jerryyue]

I’m surprised how he didn’t fully understand it trying to explain it. It’s partially wrong.