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/sci/ - Science & Math

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4845848 No.4845848 [Reply] [Original]

Serious question, would appreciate serious answers.

Why do people believe that Quantum Mechanics actually explains what is physically happening? How can you believe this bullshit?

I'm reading "Probability Theory: The Logic of Science" by Jaynes atm and he covers how quantum mechanics is bs, and how it will take someone like Newton to come and prove that the outcomes are not probabilistic. Jaynes gives a classical analogy to the approach QM has taken (about flipping a coin) and shows that we could've done classical mechanics the exact same way. Instruments were developed to prove the predictions and that proved that Newton was right.

Now I get that we simply don't have the instruments to measure things properly (besides spin.. etc), but what the fuck? How can people believe that nature does not follow a set of laws? Why does the Quantum community shun those who try to propose ideas as to why these things happen (w/o probability)?

Anyways, my future is dead-set on working on QM. I don't mind having to do bullshit experiments in a lab just to make enough money to survive.. but as soon as I get home I know that I'll be thinking about QM and trying to create models.

I need help with a couple of things:

1) What should I learn to become a good quantum theorist that isn't full of bullshit and narrow-minded? I've asked this before but I just want another summary.

2) What should I look into if I want to study the problem of Quantum Gravity?

3) Do you know of any "classical" problems that haven't been solved yet? If so please link.

I'm in my second year of undergrad (going into 3rd).. and I've become sick and tired of all this bullshit. I hate learning things without being given the math background... and I'm willing to put in 3 hours, 3 times a week to learn a bunch of math to do QM.

Thanks!

>> No.4845863

A classical, not probabilistic, theory would certainly be more pleasing. It's just not very likely, seeing as quantum mechanics explains everything pretty well.

Also, I don't think it helps to believe that nature should work as you think it should, it'll work however it works, and that may be remarkably different to the macroscopic.

Sorry, I can't help with any of your questions.

>> No.4845874

>>4845848
step 1: don't major in physics at a liberal arts college or community college

>> No.4845885

>>4845874

I'm not in physics. I'm in Engineering and planning to take a Pure Math major on the side because I'm tired of the faggots that surround me in engineering.

Also.. I'm at the best university in Canada.

>> No.4845898

>>4845885
so you know jack shit about QM, read a book by a fringe theorist, and now want to prove 80 years of brilliant research wrong with a stroke of genius by picking up an undergrad major in pure math?

give me a break.

>> No.4845903

>>4845898
>give me a break.

I'm taking a course in QM atm.

Also I never admitted to knowing all there is to know about QM. You don't need to know everything about something to call bullshit on it.

I told you that I'm reading Jaynes' book, it thoroughly goes into the topic of QM and WHY it is bullshit.

>> No.4845904

>>4845898
also, the uncertainty has nothing to do with measurement and has everything to do with how a particle is described by QM

>> No.4845915
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4845915

>>4845848
>Instruments were developed to prove the predictions and that proved that Newton was right.
And then more instruments were developed hundreds of years later that proved he was "wrong".

That doesn't mean that his models weren't successful. It just means they weren't useful for the quantum scale.

>Why does the Quantum community shun those who try to propose ideas as to why these things happen (w/o probability)?
Because we have no feasible way of testing or observing these ideas.

It's not scientific. It's fun to speculate and think about, but we have no evidence to point us in either direction. And the only reason we've made any progress with QM to begin with is because we've accepted that, and moved on with the issue.

>> No.4845920

>>4845903
you must be taking the worst QM course ever.

the starting point with any physical theory, QM included, is that nature *does* follow a set of laws. those laws happen to be probabilistic.

see here:
http://forums.xkcd.com/viewtopic.php?f=18&t=73610#p2728818
i've bookmarked this post precisely so people like you can stop doubting QM based on how it's explained in the New York Times

>> No.4845921

>>4845903
I haven't read the book, could you sum up what the arguments are? I'm genuinely interested.

>> No.4845924

and besides, nobody ever claimed QM is explanatory. it's a model like any other. it just happens to be a damned good one, so why not run with it until it doesn't work anymore?

>> No.4845928

>>4845885
Wait which university is that?

>> No.4845929

it does follow a set of law. and nio part of quantum mechanics, anywhere, is probabilistic. its completely 100% deterministic. the only part probability comes into it is when the wave-function collapses. and we don't have any theory that works regarding that, so judging it and calling it bs is kinda retarded since its not even part of QM. even if we find out that the collapse of the wave-function is deterministic in some way, QM will still be correct. and its not that we dont have instruments to measure it, its that we cant. particles dont exist. its quantized waves. its not that hard of a concept since even Newtonian mechanics has waves in them.

1) first you must learn quantum field theory.
2) string theory, loop quantum gravity. those are the big ones.
3) construct a general solution to the Einstein equations.

there are textbooks that handle quantum mechanics from almost pure math. cant remember them now, but they exist. just get them.

>> No.4845934

I typed up quite a thorough response to the OP and 4chan refuses to accept it and is convinced it is spam.

OP pretty much everyone (especially physicists who have relied on a general sense of "physical intuition" in their problem solving) has this reaction to QM.

>>4845903
You may be reading that book but you clearly don't understand it, if that's what you're taking out of it. Look up the Bell inequalities. Hell learn some math beyond the Schrodinger equation and babby's first QM and come back.

QM isn't the whole story, and I encourage research into new interpretations of how we see the world, but those interpretations are not going to advance our knowledge by chucking all of QM out the window as "bullshit". The fact that you think so, tells me how little you understand, and how utterly impossible your quest for the "truth" is if you don't start accepting your own ignorance.

>> No.4845937

>>4845903

You seem pretty intent on disproving the theoretical framework that constitutes a huge portion of our knowledge of the universe. One guy's theoretical musings are not going to erode nearly a century of work. The fact is, unless he's got a theory that explains the data better, or thinks that the particles have been lying to us all these years, nobody gives a fuck what he thinks. I'm sure you think you're very smart, but you're not going to come to anything guys like Feynman missed, not to mention the fact that you've set yourself up for some major confirmation bias.

TL;DR give me data that QM thinks it explains, but is wrong about, or GTFO.

>> No.4845939

>How can people believe that nature does not follow a set of laws?

Oh, it's running by laws. If you think QM isn't based on tons of very real math and very real experimental results, you just don't understand what you are doing yet.

These "laws" may not be deterministic and objective, but probabilistic and relative: that's the point. Nature doesn't have to be intuitively acceptable to human minds. Most of Newton's wasn't at the time, either.

btw, easy for Jaynes to say he wants a Newton to come along and show that QM is BS. That's just an article of faith on his part. The more likely thing will be that another Newton will come along and wrap everything up neatly, and it will be MUCH MUCH STRANGER than you can even imagine now.

>> No.4845947

What do you need to learn QM for? Your question can be answered better if you specify the engineering field you need it for. There's certain math you need to learn for certain fields.

>> No.4845942

>>4845921

HMm.. I can try. But please don't look down on the arguments based on my presentation of them.

He starts off by describing the tossing of a coin (in general). We come to the conclusion that it will land 50% of the time on heads and 50% on tails. We can create a model to show this easily.

Now people may speculate as to what factors effect this behavior.. but it takes a special genius (like Newton) to come around and show that it is NOT probabilistic.. and in fact can be calculated by taking into account the velocity it is tossed at, whether or not it is facing heads or tails when it is tossed, how long it is in the air for (and how far is it being tossed), etc etc.

Until someone like this comes and creates a nice model for QM we're stuck with probabilistic outcomes. I can give you the section of the book because it's a VERY good read and I recommend it.

>> No.4845951

>>4845942
oh fuck, really? that's it?

http://en.wikipedia.org/wiki/EPR_paradox

>> No.4845948

>>4845885
One thing to keep in mind, OP:

Science and Math go hand-in-hand. But they're not the same thing.

Science does not produce results with %100 accuracy. There's always error, and that's not something we're ever going to get rid of. That's just what happens when you have humans doing science.

We inherently can't "prove" that the universe is deterministic, because we are constantly producing imperfections. That's just how it is, and QM has already accepted this and moved on with the issue.

It's not that Newton is wrong. It's just that we've found QM to be far more conventional.

>> No.4845959

You sound pretty narrow-minded yourself. You've already decided that any theory which is fundamentally stochastic is "bullshit." Shouldn't the test of whether a theory is "bullshit" be whether it works?

>What should I learn to become a good quantum theorist that isn't full of bullshit
Yeah, not wanting to read things that don't match your preconceptions, that doesn't sound narrow-minded at all.

>> No.4845962

>>4845942
a problem with that analogy is that it is possible to see in QM if something has underlying rules, or if it is quantum mechanical with a wave-function that collapses at the end randomly. the problem is that all the tests have shown it is impossible to be some underlying rule. they are continually improving this tests but at the moment it favors QM with overwhelming accuracy.

>> No.4845964
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4845964

>>4845942
>but it takes a special genius (like Newton) to come around and show that it is NOT probabilistic
And it takes a special genius to show that is IS probabilistic.

And we've had plenty of scientists who did that.

>> No.4845965

>>4845959

? I'm willing to read them. I'm willing to learn ALL of it, and ACCEPT it.

I think you're taking me literally for saying "bullshit". I don't mean to say that very harshly. I just think that something better must be out there and it is up to OUR generation to figure it out.

>> No.4845968

>>4845948
this is a retarded post.

>> No.4845970

>>4845965
see
>>4845951
>>4845951
>>4845951
>>4845951
>>4845951
>>4845951
>>4845951
>>4845951
>>4845951

>> No.4845976

>>4845970
I am.. I'm reading it atm (sorry for not replying)

>> No.4845981

>>4845970
>>4845976

Okay, I've read through half of it and this shit is REALLY interesting.

This is the kind of shit I love, and its one of the main reasons I called QM "bs"... I wanted to get these kind of ideas out of you people.

Thanks so much for this! If you have anything similar please let me know.

Also, the questions following

> I need help with a couple of things:

are still open

>> No.4845984

>>4845965
Fair enough. If you want to learn quantum mechanics, you should read a textbook. The texts by Griffiths and Sakurai are popular. You will likely find you need to learn some prerequisites.

>> No.4845989

>>4845984
Good stuff. I'm on Chapter 3 of Griffiths atm.

>> No.4845995
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4845995

niggo pls

>> No.4846002

>>4845995
A true genius!

>> No.4846026

>>4846002
also, the isaac newton of economics

>brilliant
>insightful
>important
>dead wrong

>> No.4846027

>>4845965
>I just think that something better must be out there
But does the "something better" replace the existing model, or does it improve upon it?

The ideas behind QM weren't made to contradict the existing Atomic models. They were made to explain the structures of atoms.

After we've established a model of QM that we're satisfied with, then we'll start building off of that.

>> No.4846023

A 2nd year engineering student taking a quantum mechanics course? Don't piss me off. You're taking your last general physics course which poorly glosses over QM over the course of a couple weeks.

QM is a probabilistic model, yes, but QM itself does not say that all events are probabilistic. That comes from the Copenhagen interpretation of quantum mechanics, which is a certain marriage of philosophy to the mathematics of QM. Events are acausal with this approach.

The many worlds interpretation says that the universe splits into parallel universes; there's no randomness at all, everything happens. The Bohm interpretation argues that there is a deterministic mechanism for wavefunction collapse, but it's unknowable.

QM is definitely not bullshit. It's experimentally verifiable and works extremely well. QM's application to semiconductors, integrated circuits, etc., is the reason you have a fancy smartphone and laptop.

To answer your query: there's a good math book called "Mathematical Methods in the Physical Sciences" by Mary Boas. Start there.

>> No.4846033

>>4846030

>3) Do you know of any "classical" problems that haven't been solved yet? If so please link.
I can't think of any.

>I hate learning things without being given the math background... and I'm willing to put in 3 hours, 3 times a week to learn a bunch of math to do QM.
If you want to be able to do standard undergrad QM, it shouldn't take you more than a couple months. Make sure you're really solid on Linear Algebra, and then find a good QM textbook with practice problems such as Zettili.

The problem for you is going to be letting go of your biases. If you keep up the attitude that "it can't be this way" then you're never going to get through a textbook.

>> No.4846030

> How can people believe that nature does not follow a set of laws?
It does, they are just probabilistic in nature. Just because you want the universe to work in a certain way doesn't mean it has to.

>Why does the Quantum community shun those who try to propose ideas as to why these things happen (w/o probability)?
Bell's Theorem

>1) What should I learn to become a good quantum theorist
>2) What should I look into if I want to study the problem of Quantum Gravity?
To have a pretty perspective on the current state of physics: besides a shit-ton of math, you'll need to learn the following from a theorist's perspective:
-Quantum Field Theory/Standard model (obviously)
-General Relativity and its theoretical tensor-scalar spin-offs like Einstein-Cartan theory and other metric theories with possible non-zero torsion.
-String Theory/String Field Theory/M-Theory/whatever the fuck you want to call it
-Loop Quantum Gravity

>that isn't full of bullshit and narrow-minded?
It seems the narrow-minded one is you. You refuse to accept inherent probabilities because they are unfamiliar and make you uncomfortable.

Do you really think it's as simple as "well, there should be this hidden variable x" to which the entire physics community replies "oh yeah, we never thought of that before" ?

(to be cont.)

>> No.4846035

>>4845968
this is a retarded post.

>> No.4846038

>Serious question
>How can you believe this bullshit?

Yeah, I was looking forward to having a discussion with you, but it looks like your mind is already made up. Also, do you even read what you type?

>> No.4846043

>>4845939
You should add that science has nothing to do with believing shit. Its all about proving and explaining stuff.

>> No.4846046

>>4846033
metric. i thought you know GR. and you cant think of any problems in it that hasent been solved?

>> No.4846051

Bell's theorem has nothing to do with whether there's a deterministic theory underlying QM. It has more to do with locality. It's still worth learning and understanding, though. And frankly, this stuff about whether there is determinism seems rather minor in comparison with the other stuff about QM we don't know.

>> No.4846052

>>4846043
True. At the bottom of it all, science doesn't care what you want to believe. It'll do what it does anyway!

>> No.4846067

>>4846033
Thank you for both of your posts.

Once again, I'd like to stress that I didn't mean to be taken literally. I understand that nature does behave the way it does, and we need probability to model how it behaves.

Believe me, I'm very open-minded and hell... if the current theory is composed of absolute truth then who I am to say that it is wrong? I just believe that it is a worthwhile cause to search for an alternative theory

>> No.4846075

>>4846038

My mind isn't made up. CONVINCE me of your side, I'm all ears. I understand that the experiments have shown what they have shown.. without a doubt.

My problem lies in what APPEARS to be the absense of searching for an alternate theory.

>> No.4846082

>>4846046
By "classical" I assumed he was talking about non-relativistic classical theories, i.e. Newtonian problems. Though, you're right, technically GR is a classical theory.

Here's a wikipedia list of unsolved physics problems: http://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics

>> No.4846086

>>4846082
>http://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics

Tyvm

>> No.4846128

Can someone here explain to me whats the deal with all that probability in QM, what is it and how does it actually work? For me, the universe is deterministic and true randomness can never exist in this universe.

>> No.4846134

>>4846128
Do you know what polarization is? Also, that's how everyone thinks before QM.

>> No.4846140

>>4846134
Nope, no idea. Can you explain it like you would explain it to an idiot?

>> No.4846146

>>4846140
I'm OP.. watch this

http://www.youtube.com/watch?v=LPDP_8X5Hug

>> No.4846170
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4846170

tl;dr

Is there some interesting question going on in this thread or is it just troll-like (even if not intended) bs

>> No.4846205

>>4846146
Fuck my ADHD, lets forget about polarization. Just tell me, how do you actually know that it is random? What do you call random? When one thing is unobservable and impossible to predict? For me that isn't randomness, that's just a lack of information.
Here's another question:
Imagine that someone tosses a coin and it lands heads up. Now, imagine that you can somehow magically return the time to 1000 years ago and then replay the whole universe up to the date and time when that guy tossed the coin. Would he still be there, in the exact nanosecond, throwing that coin that landed heads up, or would something different happen?

>> No.4846207

So, what it sounds like you want is an interpretation of quantum mechanics which presents it as a sort of statistical mechanics where there are hidden variables. If so, I would suggest Bohmian mechanics. I am not very familiar with it myself, but it gets around Bell's inequalities by proposing non-local hidden variables. It acts like quantum mechanics under the majority of circumstances, but there are supposedly some things to do with oil drop experiments that might show the waveguide. Anyways, here be a wikipedia link for you OP:
http://en.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory

[My personal views on quantum mechanics is that it seems like a good theory which makes lots of useful statements and predictions about cases in the low energy regime. Its various interpretations are experimentally indistinguishable to date and so don't matter at the current time.]

>> No.4846219

>believing in QM
>not superior Laplacian determinism

Shiggy diggy.

>> No.4846247

>>4846205
Probably not. It's damn hard to say. But assuming that quantum effects are genuinely random, in 1000 years the chances are that something different will have happened at some point, that effects the coin toss guy in some way. But there's way too many variables to be sure of anything.

About the randomness, randomness is when an effect has no cause (someone please correct me if this is wrong). I'm in no way fit to explain photon polarization, or any other quantum phenomena, you'd have to get a book.