🗑️ 🧵 A question about Heisenberg's uncertainty principle
Hale at Thu, 7 Nov 2024 14:56:19 UTC No. 16466036
Before asking the question i wanted to point out that i'm not a physics student, so this may be a dumb one, so please don't roast me. I'm studying the first year of biology.
While studying the quantum physics chapter of general chemistry i wondered why we need ligt to find the position of a particle. I've red that heinsenberg's uncertainty princible depends on the fact that you can observe a particle only by shining a photon on it. Low frequency photons can get few details on the position because they have a high wavelenght while high frequency ones can give a good idea on the position while disturbing its momentum.
Don't particles have masses? why cant we study their positions by relevating their gravity force with three sensors? Or maybe trough their magnetic fields (if they have one)?
What are the alternatives to light?
Anonymous at Thu, 7 Nov 2024 15:01:17 UTC No. 16466039
>>16466036
You could use other particles like electrons of protons but they will be larger (lower resolution) and more massive (more uncertainty once you bang into the particle you want to measure).
Hale at Thu, 7 Nov 2024 15:40:04 UTC No. 16466074
>>16466039
Why cant we use gravity or magnetic fields?
Stop guessing start learning at Thu, 7 Nov 2024 15:42:45 UTC No. 16466079
>>16466036
Stop getting so caught up in the useless jargon in QM
stick to simple concepts.
The uncertainty principle means that qm uses non deterministic measurements.
What is a measurement?
Let's take a tape measure you use abstract numbers on the tape measure and apply them to a physical object.
As a reference point.
My dick is 6 inches. Now I have a point of reference for length.
In physics it's the same QM uses statistical or probability measurements to measure a physical particle or wave.
Since these physical cannot be observed directly you cannot precisely measure them.
Hence the uncertainty principle. The only thing certain is uncertainty as there are unmeasurable components that we cannot observe.
So it's mostly an highly educated guess
Anonymous at Thu, 7 Nov 2024 15:48:28 UTC No. 16466090
>>16466074
>Why not gravity?
We can barely detect blackhole collisions. And no one has a graviton emitter.
>Why not magnetic fields?
Reread the chapter on electromagnetism to see which particles are the force carrier. Then reread the previous reply.
Hale at Thu, 7 Nov 2024 15:52:05 UTC No. 16466098
>>16466079
ty for the reply, it makes sense to me. PS nice cock bro
Anonymous at Thu, 7 Nov 2024 20:01:43 UTC No. 16466344
>>16466036
We can use an STM (scanning tunnelling microscope) to visualize and move atoms lego-like on a surface. It uses electrostatic force. Pragmatically, who cares where the components of the atom are - they're somewhere in the atom that looks like a pea to the STM.
Anonymous at Thu, 7 Nov 2024 21:38:06 UTC No. 16466467
Gravity is hard to detect on those quantum objects. There's no quantum gravity theory either. Magnetic field and electric field are both mediated by photon.
Anonymous at Sat, 9 Nov 2024 01:05:01 UTC No. 16467805
>>16466036
This is a good understanding from the perspective of a chemist. If you want a deeper understanding, you should learn about the relationship between measurement and operators; the Heisenberg uncertainty principle tells you the uncertainty in a pair of measurements depending on how well their operators commute.
Anonymous at Sat, 9 Nov 2024 05:04:32 UTC No. 16468001
>>16466036
Measuring/Observing something requires you to interact with it in some way. This might be with a ruler, or with a Lazar that uses photons. Either some "thing" will have to interact with your subject, which will alter it ever so slightly. We have no way of "observing" something that doesn't use an instrument or light that would interact with the subject in some way. By definition, interacting with a thing alters it/causes it to assume a form.
Anonymous at Sat, 9 Nov 2024 09:15:01 UTC No. 16468106
>>16466036
It is instructive to visualise the uncertainty principle as an inverse relation between uncertainties in measurements (I.e. position and momentum). Moreover, these uncertainties change over time, with or without measurement, thus measured quantities become more/less varied (picrel) over time. Which means fundamentally, a particle evolves as a 'wave-function' as opposed to a definite, localised object. Indeed a 'measurement' is just the scattering of one wave-function off another to reduce uncertainty, which is never completely eliminated.
>Don't particles have masses? why cant we study their positions by relevating their gravity force with three sensors?
Gravity is too weak to resolve quantum effects, according to this site: https://gravityphysics.com/2018/03/
With the current most sensitive gravitational-wave detector (LIGO) the flux needed to resolve the wave-function of a low-energy electron is ~10^38 Watts/m^2 , and this can only come from supermassive black hole and neutron star collisions, because at similar energy densities for subatomic particles, the electromagnetic and nuclear forces effectively negate any gravitational effects.
>Or maybe trough their magnetic fields (if they have one)?
This is how MRI works - hydrogen ions in the body resonate with an external magnetic, and thus, emit electromagnetic radiation.
>What are the alternatives to light?
Pretty much anything with a sufficiently small Compton wavelength (https://en.m.wikipedia.org/wiki/Co
Anonymous at Sat, 9 Nov 2024 13:24:15 UTC No. 16468249
>>16466036
Not sure if its wise to explain to you these things because the proper explanation is for you to study physics in college for a few years. Anything written here is going to be simplified to a point it starts to be misinformation.
Feynman had this problem too, he said that common people asked him advanced physics questions whos answer just made no sense for them. He also said he would be asked questions about cutting edge physics like "what the latest discovery, doc?" about which no one knew much because literal new science but no one cared about things that were already known, of which he knew a lot more and could properly talk about.
Anonymous at Sat, 9 Nov 2024 13:40:44 UTC No. 16468254
>>16466036
Single atoms/particles have insanely tiny mass, which makes their gravity almost impossible to detect.
Gravity is also a very, very weak force (not "The Weak Force") in and of itself. You overcome it every time you lift something despite the entire planet Earth fighting against your efforts.
We do use atomic/molecular mass to help identify compounds by using instruments like mass spectrometers, but that mass has almost no impact in terms of the immediate surrounding region.
Anonymous at Sat, 9 Nov 2024 13:45:40 UTC No. 16468259
>>16466036
Any "alternative to light" would likely require you to "touch" the object in some way, which is just another form of interaction, and may be less precise.
Ultimately, we still don't know "why" any of this happens, of if it "really" does at all. No one has ever seen an "atom collapse into a point out of the aether", but if we think of it that way and build maths around that assumption, we can get extremely accurate models with which to make testable predictions.
It's not "perfect", or even 100% confirmed, but it works "well enough".
Many folks in QM honestly don't even care, or think about these fundamental questions. They just "shut up and calculate" because the math is often so precise. You don't "know" how your iPhone works, or "why", but it does and you can use it to do all sorts of great stuff, so there why bother trying to "understand" it. Just use it and move on. I agree this stupid, but there is a sort of Machiavellian logic to it.
Anonymous at Sat, 9 Nov 2024 13:54:52 UTC No. 16468261
Its been done but the technology to locate electrons is classified. This is the power that enables stealth aircraft BTW, its a state secret and if it was revealed the terrorists would win.
Anonymous at Sat, 9 Nov 2024 14:04:59 UTC No. 16468270
>>16466467
this.
at this point in time, it would even be legitimate to claim that an assignment of mass to a single particle is still pending.
Anonymous at Sat, 9 Nov 2024 14:39:48 UTC No. 16468307
>>16466074
>Why cant we use gravity or magnetic fields?
For gravity ts like trying to detect a golf ball falling in the middle of the ocean by watching the waves on the shore, the gravitational pull of a particle, atom or molecule is too small for us to detect with any known technology, even Earth's gravity is hard to detect at these scales (https://physics.aps.org/articles/v
Anonymous at Sat, 9 Nov 2024 15:27:54 UTC No. 16468334
There are a lot of people in this thread who don't have a complete understanding of the Heisenberg uncertainty principle. Not that I do either, but it is less a consequence of your measurement device and moreso a fundamental property of matter waves.
Anonymous at Sat, 9 Nov 2024 18:54:10 UTC No. 16468529
>>16466079
>The uncertainty principle means that qm uses non deterministic measurements.
no, that's not it at all
the uncertainty principle states that certain types of properties of particles can't be fully known simultaneously.
position and momentum are the most well known examples.
however, an uncertainty principle exists for any "non-commuting" measurements.
quantum systems are fully described by their quantum state, which is a vector
in general, vectors can be uniquely represented w.r.t. a chosen basis (i.e. coordinate system)
in quantum mechanics, each kind of measurement is associated with a particular basis
in the standard interpretation of QM, when you make a measurement of a quantum state, it collapses to one of the measurement basis vectors with a probability equal to the (square modulus) of its coordinate w.r.t. that basis vector.
if you immediately repeat the same measurement, then you would measure the exact same thing with probability 1 because the quantum state is now equal to one of the basis vectors.
the uncertainty principle comes into play when two different measurement operations A and B.
if you perform measurement A on a quantum state, you probabilistically get some value based on the coordinates of the quantum state w.r.t. the A basis, and the quantum state collapses to the A basis vector associated with that value.
if you then perform measurement B, two things can happen:
1) if A and B share the same basis, then the coordinates of the quantum state w.r.t. basis B are the same as A, and you will measure the corresponding B value with probability 1
2) if A and B have different bases, then the coordinates of the quantum state w.r.t. basis B will have non-zero components for more than one B basis vector, meaning that you will probabilistically measure a value, and the quantum state will collapse to the B basis vector associated with that value
in the second case, you can never simultaneously know the properties you are measuring (see pic)
Anonymous at Sat, 9 Nov 2024 20:37:08 UTC No. 16468699
>>16466036
>Don't particles have masses?
It's momentum that matters more. Photons do not have mass though they have momentum. The "particle" is just a node in an oscillating wave.
>why cant we study their positions by relevating their gravity force with three sensors?
For such particles, the masses are so low that the force of gravity generated by them is negligible compared to anything that will ever accessible to human engineering.
>magnetic fields
Electrically charged particles will have their momenta altered by the fields as well.
Anonymous at Sat, 9 Nov 2024 20:47:06 UTC No. 16468708
>>16468529
>quantum systems are fully described by their quantum state, which is a vector
Unfortunately they aren't and such a statement is entirely inaccurate. Otherwise there would be an understanding of the motion of those particles beyond that of "flip a coin and see whether it gets heads or tails." You would have something more like "the side the coin lands on depends on the position of the coin on the person's thumb, the initial velocity applied to the coin, and how the person catches the coin" with some sort of model that one can at least use numerical methods to predict exactly which side of the coin a person lands on. QM doesn't even have the mechanistic model or anything that can really accurately be called a model. It just has outcomes and some way of determining their probabilities. Quantum Mechanics is along the order of "flip a coin 1000 times and here is the graph of all the outcomes with their odds of occurring" while the system being described, the motion of the coin and its final orientation in our example, are entirely absent. All there is is a gaggle of distributions with NO understanding of anything that's going on. That's extremely far from "quantum systems are fully described by the state function." Whereas a rock flying through the air to hit your tiny brain can have its motion completely described by a system of equation.
Anonymous at Sat, 9 Nov 2024 22:18:26 UTC No. 16468802
>>16468708
Hibert spaces are valid inner product spaces, and wave functions are accuratrly described by the Schrodinger equation
Anonymous at Mon, 11 Nov 2024 07:52:24 UTC No. 16470519
bamp