The term "quantum mechanics" sucks and we desperately need to change the name for two reasons:
1) The word "quantum" promotes all sorts of woo and shitty pseudoscience that convince retards that they understand shit.
2) IT'S NOT EVEN ACCURATE. Position is never quantized. Momentum is never quantized. Energy is only SOMETIMES quantized.
We should teach "quantum" mechanics as Matrix Mechanics as Heisenberg initially intended.
uh you dont really get why its called quantum at all do you
>>7973174
It's called quantum mechanics because of tradition, nothing else. It's a shit name that serves to only confuse people about the real physics going on.
>>7973157
so this one time I came to /sci/
... I saw this thread. Part of me wanted to help,
>>7973182
its called quantum because of the quantization of states
>>7973190
Ah yes, all of those quantized states in the free particle. I must've for-
Oh wait. You're a dumbass.
>>7973195
a free particle is the |1> state of the field
>>7973207
...what?
>>7973157
>1)
The word quantum got that rep based off the physics--i.e., the nomenclature will just develop that connotation no matter what the hell you call it
>2)
for the same reason, matrix mechanics is inaccurate as everything is not discretized by the same claim. If you're ok with 'continuous' matrices, then surely you can stomach continuous eigenvalues. Energy/spin-projection values being quantized are unique to the field anyway, so there's no confusion with classical mechanics via this 'misnomer.'
Of course, what we call quantum mechanics is purely nomenclature and plenty of other areas/concepts/etc. in physics have worse names. Calling it something else won't affect how it's taught, learned, or used--you'll just see new books on 'Matrix Conciousness' and 'Matrix Evolution.'
>>7973231
> Energy/spin-projection values being quantized are unique to the field anyway
Demonstrably false. Do you even know what the Casimir Effect is? There's clearly a classical zero-point radiation field that's Lorentz invariant and scale invariant and when you fit the classical theory to the experimental data, you find that Planck's constant simply appears as a multiplicative constant setting the scale of that spectrum. Absolutely no quantum mechanics involved.
I see what you're saying about shit like "Matrix Consciousness" and "Matrix Evolution" but I'd even be okay with Wave Mechanics or Modified Hamilton-Jacobi Mechanics since that's basically what QM is anyway. Just something that gets the woo away from the field.
>>7973220
>being this fucking illiterate in qft and still making the thread
>>7973259
What you said makes no fucking sense.
>>7973254
That's fair, my wording was suspect (funnily enough as that's the subject of the thread). I mean that these effects are unique to the quantum theory. Naturally, empirical measurements will reflect quantum behavior because our universe is quantum in nature. Planck didn't have quantum mechanics for his ideas to match data, the constant was obtained in the same fashion alongside a discretization (quantum) assumption. To say there's no quantum mechanics involved is misleading, as classically there wouldn't be a casimir effect. It's precisely a theoretical construction with virtual photon corrections that match the casimir effect.
>>7973262
Only if you're an idiot.
>>7973254
wtf. There is nothing misleading or whatever you mean by "woo" in the therm "quanta" itself. All the bs your talking about grew up on its own, and its ridiculous to blame the term
>>7973266
>To say there's no quantum mechanics involved is misleading, as classically there wouldn't be a casimir effect.
I disagree. If we change the homogeneous boundary condition on Maxwell's equations to include a classical electromagnetic zero-point radiation (i.e. it does not vanish entirely), the math all works out perfectly to explain phenomena like the Unruh Effect, Casimir Effect, and the Van der Waals forces. Perhaps this framework won't lead to such beautiful answers with the hydrogen atom but at least there does exist a classical framework for which the Casimir Effect does exist.
>>7973272
It's definitely the term and you know it.
>>7973284
As far as I know, its the same root word for "quantity" which is a pretty concrete and understandable term to adopt to mean "the smallest possible quantity of something". If Planck chose a term that was misleading in anyway, I'd consider your argument. All the far reaching BS surrounding QM is more likely due to the the strange phenomena observed in the quantum world. People will latch on to any strange phenomena and use it as a launching pad for all kinds of fantasy
It's the study of the dynamics of systems at the level where things get quantised, what's the problem?
>>7973157
>position and momentum are never quantized
What in heavens name are you talking about?
Plenty of potentials have quantized positions and momenta.
>>7973195
A free particle is a momentum eigenstate. Only one momentum value allowed.
>>7973157
>The word "Quantum" should be replaced with the word "Matrix" to stop it sounding like pop-sci"
You are aware that that would just make it worse right? "Matrix" has been memed the fuck out by the movies.
>>7973157
Kim is best waifu.
>>7973499
You clearly haven't even taken an undergrad quantum course. The spectrum of the position and momentum operators are continuous. Period. End of fucking story. You're the biggest retard in the thread, congratulations.
>>7973503
Second biggest retard in the thread. By this same logic, classical momentum is quantized because hurrrrr momentum can only equal [math]\sqrt{2mE}[/math] !!!!
Fucking retards, all of you.
>>7973334
Classical mechanics, classical electrodynamics, and classical statistical mechanics all deal with quantization at some point without a single bit of quantum theory. What makes quantum mechanics so special?
>>7973512
Still better than quantum.
>>7973749
For a free particle with zero potential, the spectrum of the momentum operator is a single value. Its a Dirac Delta distribution.
Freshman Chem majors really shouldn't be making threads demanding an entire field change it's name.
>>7973749
>You clearly haven't even taken an undergrad quantum course. The spectrum of the position and momentum operators are continuous. Period. End of fucking story. You're the biggest retard in the thread, congratulations.
What is the momentum spectrum of a particle on a circle?
>>7973157
The fundamental objects in quantum physics are quantum fields, whose excitations are quantised. Position and momentum might not (always) be quantised, but you will always get particle states. That's where the term comes from - Planck realised that EM waves come in quantised chunks. A quantum is just a particle and this is where the term "quantum physics" comes from - it's the physics of quanta, not physics where the measurements take discrete values.
>>7973758
Holy shit you doubled down on your tard! You're so wrong that it's literally in Griffiths. One of the simplest QM textbooks out there, and you don't even understand one of the most fundamental parts.
The spectrum of the momentum operator is NORMALIZABLE to the dirac delta function. It is NOT actually the dirac delta function. Example 3.2 in Griffiths in section 3.3.2 titled "Continuous Spectra." Wow, I wonder why it's titled that?
Once again, congratulations, you're the biggest fucking tard in the thread.
>>7973766
>What is the momentum spectrum of a particle on a circle?
that's.....angular momentum....................
why is everybody in this thread such a retard
>The fundamental objects in quantum physics are quantum fields, whose excitations are quantised.
By this logic, statistical mechanics should be called quantum mechanics because its constituent parts are always quantized. We have one particle, two particles.... all the way up to N particles. Wow, look at that quantization!
>>7973157
What about this confuses you?
>>7973783
Did you even read the OP? I'm not even kidding, did you even fucking read it?
>2) IT'S NOT EVEN ACCURATE. Position is never quantized. Momentum is never quantized. Energy is only SOMETIMES quantized.
So fantastic, we have the title of a field that's not even accurate.
>>7973774
>that's.....angular momentum....................
No, I mean the regular old linear momentum of a particle on a circle.
Think of a particle in a periodic space.
Perhaps try studying a bit more before making yourself look stupid :^)
>By this logic, statistical mechanics should be called quantum mechanics because its constituent parts are always quantized. We have one particle, two particles.... all the way up to N particles. Wow, look at that quantization!
You're dealing with particles that would classically be described by fields. The excitations are quantised. In introductory undergrad quantum mechanics you deal with a quantised version of a single particle, and later a fixed, finite number of particles so I can see why you'd think the name is pointless - the classical theory also consists of discrete units. The first system to be quantised, though, was the EM field, and that is where the name comes from. We now understand all particles as coming from quantised fields, so the name is very appropriate at a fundamental level.
>The word "quantum" promotes all sorts of woo and shitty pseudoscience that convince retards that they understand shit
What you mean is that the terminology needs to change again, because the common folk are learning your parlance. That way, you can write papers about basic things with an exclusive cant that makes you feel special.
The word 'atom' used in it's modern context would make sense to someone from two thousand years ago in Greece. Scientology uses a bunch of initialisms and new lingo to producd it's own reality, and protect itself from criticism with an impenetrable wall of gibberish - don't be Scientology.
>>7973787
Maybe not position and momentum but the defining portion of the field deals with entities that are ultimately fundamental (as far as we know now). Things you're proposing like Matrix Mechanics already exist as separate formulations of QM. Stat mech too is simply a way to model populations of quanta -- derived from quantum mechanics.
So I'm assuming you also have a gripe with "chemistry" too? Considering the word is derived from alchemy... we must change it.
>>7973794
Sure, it's always possible to make all eigenfunctions quadratically integrable by confining a particle to some limited portion of space. The boundary conditions "quantize" the continuous spectrum but that's only a property of the boundary conditions and of our model. By your shit logic, a vibrating string is also "quantized" because you can only have specific resonance frequencies.
>>7973259
This
>>7973853
Ah yes, the weeaboos on 4chan are clearly masters of qft.
>>7973820
All I was saying is that momentum doesn't necessarily have a continuous spectrum, specifically:
>Position is never quantized. Momentum is never quantized.
Also, I'd say it's a result of the topology of space, not boundary conditions. Momentum will always be discrete if the topology of space is closed (i.e compact and without boundary).
>>7973195
But any particle confined in a finite space has quantized Energy levels anon.
That these states look continous is only the result of the enormous amount of states.
This is why the transitional partition function is described by the DeBroglie wavelength and the grand partition function must be introduced for low volumes and masses.
Cant get much more free than an electron in a metal or a gas particle
>>7973887
This is basically a quote from Merzbacher, I don't remember where though. The classical analogy is like how resonance frequencies are quantized on a vibrating string, but we know frequency isn't actually quantized.
>>7973157
The quantum pseudoscience memes came after quantum mechanics.
>>7973157
>woo and shitty pseudo science is caused by the term quantum
You are confusing effect and cause. If it had a different name, then retards would use that other name to sell their bullshit.
"Quantum mechanics" is attractive to snake oil salesmen because the underlying theory is complex and confusing to the general public.
>>7974306
Okay, so it looks like you're not so much of a retard. I'm sorry about that.
Could you expand on what you're saying? To me it seems like a condition we impose and that's it. We demonstrate in undergrad QM that momentum space with homogeneous boundary conditions is a continuous spectrum and as we impose the inhomogeneous cases, the eigenfunctions do become quadratically integrable and they become "quantized", but only in the same sense that frequency is "quantized" on a vibrating string.
>>7973157
>Position is never quantized.
Tight binding
>Momentum is never quantized.
Particle in a box
The point is that there are a set of numbers which describe the system that can only change discontinuously. Those numbers are tied to observables, but not always to position, momentum, or energy. Spin, for example, is always quantized.
>>7974339
Read the rest of the thread. Tight binding and particle in a box are boundary conditions we impose to make the eigenfunctions square-integrable but it's really analogous to how frequency is "quantized" on a vibrating string.
>>7973768
Some systems having continuous spectra doesn't mean all do
>Griffith's
Oh, your in your intro QM class. That's cute.
>>7973774
>That's angular momentum
No, he asked you about the momentum. What's the momentum for a particle in a ring?
>>7974357
The momentum eigenstate of the free particle is a delta function.
>>7974881
I'm using Griffiths as an example of how retarded YOU are. You're literally so retarded, so unfathomably unable to grasp even the most basic of QM concepts, that Griffiths, fucking GRIFFITHS, proves you wrong.
>>7974884
Read the rest of the thread.
>>7974888
No, it's NORMALIZABLE to the delta function. You're just as retarded as the other guy. You and this other guy... I just don't get it. You can literally just google "momentum eigenstate free particle" and find out that it's not the delta function. Are both of you so utterly retarded or just so unable to muster the smallest amount of self-awareness to think "you know, maybe I should just google this to make sure?"
>>7974907
The spectrum of the particle number operator is always quantized, as is its integral over all space.
Quantum doesn't fundamentally refer to the fact that there are discrete energy levels or momentum states, it refers to the fact that fields can be interpreted as particles, or "quanta."
Also, if you want to get super technical, there's also the fact that spin is always quantized. If you think it's stupid to call it quantum mechanics because literally not every quantity in the theory is discretized, it's just as stupid to call it matrix mechanics because not everything is a matrix.
OP has already admitted he is getting his quantum knowledge from Griffith's. This thread can safely be abandoned.
>>7976292
Same butthurt guy who said that the momentum eigenfunctions are the Dirac delta. I used Griffiths as an example of how retarded you are, and that's it. I cited Merzbacher later in the thread, who I like more than Sakurai too.
Fuck off from my thread, retard.
>>7976397
>everyone in the history of this field is wrong
>no, you are the retards
You've read some wikipedia articles after your first QM lecture and think you're hot shit, I guarantee it.
>>7973157
>Position is never quantized
This is not true. For instance to make mathematical sense of something like the path integral you generally have to quantize spacetime.
[math] \vec x \to \vec a\varepsilon [/math]
[math] \vec a \in {\mathbb{Z}^n}[/math]
[math] \varphi \left( {\vec x} \right) \to \varphi \left( {\vec a\varepsilon } \right) \equiv {\varphi _a}[/math]
Then we define, [math] Z \equiv \mathop {\lim }\limits_{\varepsilon \to 0} \int {\prod\limits_{\vec a \in {\mathbb{Z}^n}} \operatorname{d} } {\varphi _a}{\left( {\frac{{2i\pi }}{{{\varepsilon ^{n - 2}}}}} \right)^{ - 1/2}}\exp \left( {i{S_\varepsilon }\left[ \varphi \right]} \right) [/math]
where [math]{{S_\varepsilon }\left[ \varphi \right]}[/math] is a discretized version of the action.
>>7973157
>Position is never quantized. Momentum is never quantized. Energy is only SOMETIMES quantized.
how much energy is there in an electron cloud, onii-chan?
>this thread
Quantum mechanics is "Quantum" and "Not Quantum" at the same time, until you measure it
>>7973157
Honestly I don't disagree with you that the term is a not that good regarding the theory as a whole. I disagree that "Matrix mechanics" or anything else is better than quantum though.
However it makes a damn lot of sense when you arrive quantum field theory. What you do in QFT is exactly what it says in the name: you quantize fields. The fields are described as an infinite sum of creation and annihilation operators that create and annihilate the quanta, which are the particles of the theory.
>>7976442
You are objectively wrong and I've cited a chapter in one of the simplest QM books to understand. Is your only response "no, u!!!!!!!"?
God help you because you are so retarded you don't even realize it.
>>7976662
>I've cited a chapter in one of the simplest QM books
Actually you've cited an example in book that shows the spectrum of a particular operator is continuous. But whatever, this thread is retarded anyway.
>>7976465
Finally a not retarded response.
This is arguable, and one of the only arguments I'll allow, but it just doesn't follow correspondence into general relativity. All of our experiments demonstrate space to be continuous and the metric tensor is defined as being continuous.
I'm also iffy on whether or not "quantized action" is correct or not. I mentioned earlier in this thread that Planck's constant can be described as a multiplicative scale factor on /classical/ zero-point radiation that's Lorentz and scale invariant.
>>7976701
The jackass I was responding to thinks that the momentum eigenfunctions are the dirac delta function. He's a straight up retard.
Do you just want me to respond to the post? Because I already saw it and decided not to. I've answered it earlier in the thread.
>>7976709
You said that because other things involve discrete quantities, quantum mechanics is not uniquely descriptive.
But you're wrong that quanta are the fundamental elements of stat mech. Statistical mechanics of continuous fields is a pretty important part of the subject. Unless, of course, you are talking about QUANTUM statistical mechanics, in which case the quanta of quantum theory are indeed the fundamental objects of study.
The reason we call it quantum mechanics is because quanta are the fundamental objects of study. So it's a pretty apt name.
>>7976703
>This is arguable, and one of the only arguments I'll allow, but it just doesn't follow correspondence into general relativity. All of our experiments demonstrate space to be continuous and the metric tensor is defined as being continuous.
Yeah I know, but does a measure like [math] \mathcal{D}\varphi = \prod\limits_{x \in {\mathbb{R}^n}} {\operatorname{d} \varphi \left( x \right)} [/math] really even make sense?
>>7973157
>The term "quantum mechanics" sucks
u suck m8
>>7973157
Its the mechanics of things we call quanta, whats the issue?
i really wonder what % of posters ITT have autism, it's in the 90s at least
I think what that other guy was referring to was the free particle eigenstate in the momentum representation.
