/sci/ - Science & Math

[Anonymous No.10321644]

What's the deal with wave particle duality?

Do particles turn into wave packets and visa versa at random, or are "particle" and "wave packet" just different mathematicaly ways of describing the same thing and you just use whatever is more intuitive at a given moment

[Anonymous No.10321654]

>>10321644
>are "particle" and "wave packet" just different mathematicaly ways of describing the same thing and you just use whatever is more intuitive at a given moment
It’s this

[Anonymous No.10321657]

>>10321654
oh. And do both of them behave randomly, or is it only particles?

[Anonymous No.10321665]

>>10321657
>do both of them behave randomly
im not that guy but this is kind of a deep question with no answer. although technically the schrodinger equation is entirely deterministic

[Anonymous No.10321682]

>>10321665
if it's entirely deterministic though, wouldn't that just mean that the particle description is wrong?

[Anonymous No.10321697]

>>10321657
>behave randomly
In what way?
>both
>only particles?
I think you still don’t understand wave-particle duality. The classical concepts of particles and waves as two different types of objects doesn’t actually describe what we now believe to be their true nature. It’s not that sometimes things are waves and sometimes they’re particles, or that they’re both at once, or that they’re neither. Electrons, photons, etc. are wave-particles. They are wholly different classes of things that depending on their interactions, sometimes exhibit properties of classical waves and particles.

[Anonymous No.10321709]

>>10321682
No, because of uncertainty. Deterministic but ultimately uncertain might as well be stochastic

[Anonymous No.10321711]

>>10321697
they're two ways of describing one mathematical entity right? When you're describing the interactions as a wave packet, is any facet of their behavior intrinsically random?

[Anonymous No.10321715]

>>10321709
What's the difference between uncertain and non-deterministic?

[Anonymous No.10321727]

>>10321711
>they're two ways of describing one mathematical entity right?
Sure but wave-particles are not mathematical abstractions. These things exist.
>When you're describing the interactions as a wave packet, is any facet of their behavior intrinsically random?
In what way would it be? Equations and laws governing the quantum realm can be seen as statistical processes, but there is still a sort of cause and effect to them. It’s not entirely “random” in the sense that we can’t have at least some idea of how a quantum system will behave.

[Anonymous No.10321757]

>>10321727
>Sure but wave-particles are not mathematical abstractions. These things exist.
I never said they didn't

>In what way would it be? Equations and laws governing the quantum realm can be seen as statistical processes, but there is still a sort of cause and effect to them. It’s not entirely “random” in the sense that we can’t have at least some idea of how a quantum system will behave.
When I ask if it's random, what I mean is whether, if someone gave you a wave equation for a closed system, you could predict what that equation would look like at any point in space and time with 100% accuracy

[Anonymous No.10321782]

>>10321757
>I never said they didn’t
You kept using the word “mathematical” to describe the concept. I didn’t want you to think it was a purely math based thing.
>you could predict what that equation would look like at any point in space and time with 100% accuracy
You can predict what the wave equation will look like at any point in time or in a general area. But the specific measurement of position and momentum of objects is not 100% certain, and probabilistic in nature

[Anonymous No.10321791]

>>10321715
ok so this is much more complicated, but i agree with the guys you replied to:

schrodinger's equation IS deterministic, but the problem is that when we interact with a system (described determinsitically as a superposition of states, ie schrodinger's cat thought experiment) the system is then thrown from multiple states into a single state (wave function collapse) and HOW that state is chosen is seemingly NOT deterministic. (In other words, one could view the problem being the fact that "any two non-commuting operators (that may exist in the Schrödinger equation) can lead
to two distinct observables having simultaneous reality" i.e. that reality exists as a superposition of states.)

THUS we get hidden variable t heories to try to remedy this disturbing reality. the idea is that QM is missing something (hidden variables) that will remedy this indeterminism. Hidden variable scan either be local or nonlocal, meaning that objects are either influenced only by their immediate surroundings (locality) or that entire universe as a whole (nonlocality). Sadly, Bell's theorem shows that qm is incompatible with local hidden variable theories which leads us to some equally disturbing other options. So this boilds everything down to a couple options: 1) QM is w rong, 2) the universe obeys local rules but there's no underlying hidden variables and thus we will never have a deterministic description of the universe (what this really means, i have no idea), 3) that particles can communicate to each other faster than light and across time and consequently appear to be acting at random by some heretofore unknown method (nonlocality) or 4) god is dabbing really hard on us making it look like qm is true when it isnt

[Anonymous No.10321809]

>>10321782
but don't those only matter if you're trying to describe it as a particle?

>>10321791
when the wave function collapses, does the wave function itself physically change?

[Anonymous No.10321828]

>>10321809
>does the wave function itself physically change
as far as i'm aware, this is the problem; that in order to observe a system you have to fuck with it. we can't observe a system in multiple states because we collapse the wavefunction by trying to observe it. it's possible that it doesn't happen at all. there's all sorts of interpretations here i believe, like the copenhagen interpretation and the many worlds theory etc.

[Anonymous No.10321839]

>>10321727
>Sure but wave-particles are not mathematical abstractions. These things exist.
based

[Anonymous No.10321842]

>>10321828
So neither the wave description nor the particle description can explain things entirely?

[Anonymous No.10321881]

>>10321842
>So neither the wave description nor the particle description can explain things entirely?
im not sure what you mean, schrodinger's equation "describes changes over time in physical systems where quantum effects, such as wave–particle duality, are significant". it describes these systems basically perfectly as far as we are aware, which is why i mentioned god dabbing on us earlier

the problem is that we apparently inherently cannot observe a system without "collapsing the wavefunction", but this does not mean schrodinger's equation isn't useful. while it cannot be derived from anything, it has held up perfectly experimentally and while i havent really had to use it yet it's apparently used " to find the allowed energy levels of quantum mechanical systems (such as in transistors)."

[Anonymous No.10321886]

>>10321809
>but don't those only matter if you're trying to describe it as a particle?
you mean position and momentum? nope, waves have that too. think of wave packets

[Tuba Jam No.10321920]

>>10321727
>wave-particles are not mathematical abstractions. These things exist.
How do we know, without observing directly, that they really are wave-particles and not 5 dimensional imps or something else which only behaves as a wave-particle in from our perspective in our model of physics?

[Anonymous No.10321923]

>>10321881
In other words, we can assume the universe is acting deterministically, but we have rigorously proven that it's physically impossible to get a 100% clear image of the universe from the inside?

>>10321886
but the momentum is just the wavelength and the position is just where waves are densest. Neither of those make quantities make sense except under very specific conditions. They're just approximations of the wave function

[Anonymous No.10321926]

>"""physicists""" try to explain qm
so glad I learned it through theoretical comp sci lmao

[Anonymous No.10321931]

>>10321842
>>10321881
my answer there was kind of bad and wrong but im getting lazy and its like 1am, also i didnt really understand the question

[Anonymous No.10321938]

>>10321920
or more specifically, how do we know that it's not just the wave function, and the particle stuff isn't just a metaphoric shadow on the wall?

From what I'm hearing, it sounds like the wave function is clearly deterministic, the problem is that we don't have a way to conclusively prove it so we're just changing the definition of true to suit our circumstances

[Anonymous No.10321941]

The "wave" part of QM is pretty misleading. The intuition behind those statements assume you understands how waves behave, but for general discussion about what are universally accepted results of QM, there is no need to talk about it. What no one is going to disagree is that with the usual particles and interactions we observe all the time in the lab, it seems that the evolution of these systems is not deterministic even if we have "classical data". For example, if we measure the position and velocity of a proton far away from another one, classically, it's a popular exercise to find the trajectory it follows. In QM, you can only calculate the probability of different trajectories, but you can never be 100% sure to will follow certain trajectory. Know I said "measure the position and velocity" which sound like I'm going against Heisenberg uncertainty principle, which is not really true, you can put a sensor at some place that when is hit by a particle, you know the particle is there and by the recoil, you know the velocity, the idea is that even if a priory you know that the electron will that position, even if you set you beam to a specific intensity, your measuring apparatus will still measure a really big spectrum of velocities, outside what you set as experimental error (if you have a good set up). While there are other observables that you can measure "simultaneously" which actually means, having information of one, gives you proper information about the other one. Now, the wave aspect comes when you see that not only the mathematical description of whatever has the information is similar to what is learned in wave mechanics, the actual predictions and experiments look almost the same as if you had some sort of wave (double slit, brags law, tunelling). The dynamics are weird, and the reason for this is basically the whole debate of properly interpreting QM.

[Anonymous No.10321943]

>>10321923
no because which state is chosen from the multiple superimposed states is seemingly entirely nondeterministic and nothing has been proven (yet?)

i guess technically, after rereading what you wrote, yes i guess schrodinger's equation doesn't really "explain things entirely" as it has only been solved for a hydrogen atom still. it's possible that it's impossible to explain things entirely so it's hard to really say that.

physics at the moment really wont give you any kind of answers, come back in a couple centuries maybe

[Anonymous No.10321953]

>>10321923
>but the momentum is just the wavelength and the position is just where waves are densest.
No, I don’t know where you’re getting this from. Momentum and wavelength are related but they’re not the same. And if there’s a position where waves are densest, then that IS a position. These are things that describe both particle and wave behavior.
>Neither of those make quantities make sense except under very specific conditions. They're just approximations of the wave function
What conditions?

>>10321938
If you choose to believe that wave-particle duality means that everything is waves, and they sometimes exhibit particle behavior, then okay. That’s a different interpretation of QM.
>From what I'm hearing, it sounds like the wave function is clearly deterministic
Yep
>the problem is that we don't have a way to conclusively prove it so we're just changing the definition of true to suit our circumstances
Nope you almost had it. The wave function is deterministic. But there is an uncertainty in how we measure momentum and position. They’re related things but not exactly the same.

>>10321926
I’m just a geologist whoops

[Anonymous No.10321971]

>>10321943
>>10321953

are we sure the things we're measuring even have an objective value?

Like, if you add two sine waves together they don't have an objective wavelength anymore unless they have the same wavelength wavelength is only defined for an individual sine wave. And sure you could make it so you're adding 999 sine waves that are equal in wavelength and 1 that's slightly off and you can say that they have a wavelength with some margin of error, but really it's not defined anymore and you're just approximating something that can't have a definite value anymore

[Anonymous No.10321986]

>>10321971
>are we sure the things we're measuring even have an objective value?
This is getting into philosophy territory.
And all that stuff about adding waves, I don’t get your point. Waves interfere with each other but they still have wavelengths

[Anonymous No.10321998]

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[Anonymous No.10322003]

PSA: anyobidy who makes a post like this is asking to receive all the most epic troll counter attacks of all time, thanks to autistposters. good luck

[Anonymous No.10322085]

>>10321971
i dont know what you mean about wavelengths. have you heard of fourier series? you can add waves together, its called constructive interference. this happens all the time in ways you can literally see (rogue waves)

[Anonymous No.10322703]

Atom is a state of mind.