Quantum weirdness

Advances in the investigation of the physical universe we live in.

Re: Quantum weirdness

Postby Typhoon » Sat Jan 02, 2016 2:54 pm

Simple Minded wrote:
noddy wrote:
Simple Minded wrote:
these types of replies kinda make me feel sorry for Typhoon as a moderator. PhD's must get lonely for intelligent, adult conversation at times.....


thats what talking to yourself is for.


also splains the fondness for girly pics.


In most countries, scientists in the physical sciences are often notorious hound dogs.

[The Steve Buscemi character, called Rockhound, in Armageddon is an amusing fictional example.]

It is only in the US that the Big Bang Theory stereotype of the nerd has some validity.

Many renowned physicists had/have unconventional personal lives.

Einstein had numerous multiple affairs including a simultaneous mother + daughter pair who fought over him.

Landau was notorious as a lady's man.

Feynman was a known lady's man.

Schrodinger had two wives, believed in free love, and is said to have come up with his famous equation between bouts of wild sex with a colleague's wife at a mountain cottage retreat.

C. N. Yang's second wife is some 60 years his junior.
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Re: Quantum weirdness

Postby Typhoon » Sat Jan 02, 2016 3:38 pm

Simple Minded wrote:
Typhoon wrote:
Simple Minded wrote:
Typhoon wrote:That the physical universe operates according QM at the fundamental level has now been established by experiments.

The local reality objections of Einstein and others are now D.O.A.

Whether people are comfortable, or not, with this empirical reality is frankly irrelevant.
The problem for many people it that QM is different from their everyday macroscopic experience.

Anyways, to understand QM, one should as a minimum understand the double-slit experiment.


A very sensible explanation, yet also very religious sounding. Perhaps reality is determined primarily by one's faith. :?

Which mountain are you climbing or descending...... right now? ;)


Not sure how it is "very religious sounding".

I'm not aware of any religion based on statistically significant empirical evidence acquired under reproducible conditions.

Rather all religions that I can think of are based on metaphysicals claim that require belief, or in my case, a suspension of disbelief.
A set of historical irreproducible results.

....

It's a problem as old as civilization. Euclid is said to have replied to King Ptolemy's request for an easier way of learning mathematics that

there is no Royal Road to geometry.


My previous comments were made somewhat tongue in cheek, ;)


So I gathered.

Simple Minded wrote:but this is exactly what I was eluding to. To those who have made the effort and expended the discipline, Calculus, Differential Equations, or QM is understandable, and useful as tools to obtain further understanding of the world.

The "scientific expert" can make the same claim to the less experienced/less practiced outsider as the "religious expert." "Duplicate my hours of study (or prayer) in my field of expertise, and you will agree with my perspective."



Agreed.

Simple Minded wrote:To expect the concert pianist, and the figure skater, who both have 20,000 hours of practice in their respective fields, to agree is naïve.

Now to the outsider/less studied, what to think when QM experts or the religious experts disagree?

Climate science for example. Different lines of reasoning, seem very similar to different types of faith. Disagree, get excommunicated, and hopefully, there is another church down the road that will accept your thinking.


One major difference between QM and "climate science" is that the former is based on lab experiments with the degrees of freedom highly constrained whereas the latter is based entirely on observational data with many known and unknown degrees of freedom. In other words, many labs can perform and/or reproduce the same QM experiments whereas there is only one earth and that one earth is a dynamic driven nonlinear system far from thermodynamic equilibrium. I.e., a system with many known unknowns and probably even more unknown unknowns.

Simple Minded wrote:The answer of course is that "science is never settled" but simply the best available method with our current level of understanding/information/practice/tools. As you have noted, "experts" have a lousy track record in predicting the future. QM at work? (tongue in cheek)

Funding, politics, and the desire for fame muddy the water. The recent article someone posted that the "popular views change when the rock stars of current accepted opinion die" was an excellent example.


Agreed.

It is interesting that three very different fields currently have "rock star" problems.

The first is HEP theory, high energy elementary particle physics theory, wherein a group of people who have devoted their professional careers to string theory, a hypothesis with no testable predictions after 30 years of intense effort, go around promoting string theory as an established scientific theory to the lay public*.

The second is astrophysics theory, wherein a group of people who have devoted their professional careers to big bang theory, a hypothesis with known multiple problems, go around promoting multiverses as a solution and as an established scientific theory to the lay public.

The third is "climate science", wherein a small group of no-rate scientists have managed to raise a weak speculative hypothesis, mostly likely nothing more than an artifact of systematic biases in data analysis and of gross underestimation of statistical and systematic uncertainties, to the level of a global quasi-religious dogma with fanatical adherents among the lay public. It is here that one encounters scientists being regarded as an infallible priesthood.

As for QM, it has passed all precision experimental tests to date.
The rival local reality theories have not, and can thus be ruled out, and no one has proposed, despite nearly a century of criticisms, another viable alternative theory to QM. So until someone does, I'll stick with QM and leave the supposed philosophical questions and objections to others.

*Some of these proponents hubris is of an entirely new level in that they advocate rejecting the scientific method in that string theory need not make and pass testable experimental predictions.
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Re: Quantum weirdness

Postby Simple Minded » Sat Jan 02, 2016 4:14 pm

Parodite wrote:
Simple Minded wrote:Weinberg's statement seems sensible. Imagine how many topics could be substituted for QM in the above sentence. Which is nothing more than saying "Today, I or we know only what we know. Tomorrow we may know more, or no longer believe what we believe today."

I think there are some theories out there that the human brain is consistently being re-wired based on knowledge and experience.

Fred, Bill, Joe, and Sam have each spent 20,000 hours studying music, religion, physics, and paranormal activity. Why would you expect them to experience reality similarly?


I don't think it is that hopeless. Just one example where Fred Bill Joe and Sam are being fooled by pop-sci folk who tell them what happens in the double slit experiment:



How you connected "hopeless" to any on my posts astounds me. The aspect of humanity that I find endlessly fascinating and entertaining, especially in cyberspace, is that no matter what one posts, the interpretation is entirely up to the reader/observer. It will be a truly dull world when human communication is perfected.

We're all psychics when it come to predicting the non published intent/perspective of others... and we all suck at it. Equality at last! :P

One expects the laymen, with knowledge a mile wide and in inch deep to misunderstand each other, IMSMO, it is good to know that "experts," with knowledge an inch wide and a mile deep do the same.

It would not surprise me if most discoveries, scientific and otherwise are due to miscommunication or error.
Last edited by Simple Minded on Sat Jan 02, 2016 4:23 pm, edited 1 time in total.
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Re: Quantum weirdness

Postby Simple Minded » Sat Jan 02, 2016 4:16 pm

Typhoon wrote:
Simple Minded wrote:
Nonc Hilaire wrote:
noddy wrote:
Nonc Hilaire wrote:I keep watching the 'Beautiful Women' and 'Sex' threads for evidence from Typhoon's double slit experiments, but I am starting to have my doubts regarding the existence of this phenomenon.


http://www.iflscience.com/health-and-me ... two-vginas

Amazing. One for everyday; one for special occasions.


. . .

these types of replies kinda make me feel sorry for Typhoon as a moderator. PhD's must get lonely for intelligent, adult conversation at times.....

. . .


Please don't worry on my account in this regard. I have plenty of people, friends and/or colleagues,
with whom I can and do discuss physics and other fields of science and engineering.
.


also tongue in cheek
the good news: there appears to be about 320 million different opinions about America is.
the bad news: except for mine, they're all wrong.

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Re: Quantum weirdness

Postby Simple Minded » Sat Jan 02, 2016 4:18 pm

Typhoon wrote:Feynman was a known lady's man.

Schrodinger had two wives, believed in free love, and is said to have come up with his famous equation between bouts of wild sex with a colleague's wife at a mountain cottage retreat.



Schrodinger's obsession with pussy is well documented. The rest is news to me.

see, I am willing to learn. ;)
the good news: there appears to be about 320 million different opinions about America is.
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Re: Quantum weirdness

Postby Nonc Hilaire » Sat Jan 02, 2016 4:56 pm

Einstein had numerous multiple affairs including a simultaneous mother + daughter pair who fought over him.


Hence his famously explosive theory of relativity.
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Re: Quantum weirdness

Postby Typhoon » Sat Jan 02, 2016 6:26 pm

Simple Minded wrote:
Typhoon wrote:
Simple Minded wrote:
Nonc Hilaire wrote:
noddy wrote:
Nonc Hilaire wrote:I keep watching the 'Beautiful Women' and 'Sex' threads for evidence from Typhoon's double slit experiments, but I am starting to have my doubts regarding the existence of this phenomenon.


http://www.iflscience.com/health-and-me ... two-vginas

Amazing. One for everyday; one for special occasions.


. . .

these types of replies kinda make me feel sorry for Typhoon as a moderator. PhD's must get lonely for intelligent, adult conversation at times.....

. . .


Please don't worry on my account in this regard. I have plenty of people, friends and/or colleagues,
with whom I can and do discuss physics and other fields of science and engineering.
.


also tongue in cheek


To elaborate, given the turn in the discussion:

1/ The upper, facial, cheek; and

2/ My own

:wink:
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Re: Quantum weirdness

Postby Parodite » Sun Jan 03, 2016 1:02 am

Simple Minded wrote:
Parodite wrote:
Simple Minded wrote: Fred, Bill, Joe, and Sam have each spent 20,000 hours studying music, religion, physics, and paranormal activity. Why would you expect them to experience reality similarly?


I don't think it is that hopeless. Just one example where Fred Bill Joe and Sam are being fooled by pop-sci folk who tell them what happens in the double slit experiment:



How you connected "hopeless" to any on my posts astounds me.


Sorry, I thought you were serious, I was wrong. ;) I mean, I give specifics pertaining to the thread title and you respond with something so general and unrelated to anything I wrote here I thought you meant to suggest that we might as well close this thread being a hopeless case to further explore. So I thought.. it isn't that hopeless. 8-) Glad to know that perhaps this was not your point.
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Re: Quantum weirdness

Postby Parodite » Sun Jan 03, 2016 1:15 am

Typhoon wrote:As for QM, it has passed all precision experimental tests to date.
The rival local reality theories have not, and can thus be ruled out, and no one has proposed, despite nearly a century of criticisms, another viable alternative theory to QM. So until someone does, I'll stick with QM and leave the supposed philosophical questions and objections to others.


You misrepresent, and keep misrepresenting the controversy. No one tries to dispose of QM. Some physicists are not totally happy with qm because they feel it lacks ontological relevance. Or that it still not meshes well with macro physics and gravity. I'm just trying to figure out about the alleged quantum weirdness, what it is about and what not. A lot of smoke and mirrors there.
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Re: Quantum weirdness

Postby Simple Minded » Sun Jan 03, 2016 1:34 am

Parodite wrote:
Sorry, I thought you were serious, I was wrong. ;) I mean, I give specifics pertaining to the thread title and you respond with something so general and unrelated to anything I wrote here I thought you meant to suggest that we might as well close this thread being a hopeless case to further explore. So I thought.. it isn't that hopeless. 8-) Glad to know that perhaps this was not your point.


No problem bro. The unanticipated response is what keeps us posters and them quantum mechanics interested in the subject matter. ;)

It would only be hopeless if I had to publish something that sounded knowledgeable on QM in the next few weeks in order to make the mortgage payment.

Luckily, I count on string cheese theory as a source of income..... ;)
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Re: Quantum weirdness

Postby Simple Minded » Sun Jan 03, 2016 1:55 am

Typhoon wrote:
Agreed.

It is interesting that three very different fields currently have "rock star" problems.

The first is HEP theory, high energy elementary particle physics theory, wherein a group of people who have devoted their professional careers to string theory, a hypothesis with no testable predictions after 30 years of intense effort, go around promoting string theory as an established scientific theory to the lay public*.

The second is astrophysics theory, wherein a group of people who have devoted their professional careers to big bang theory, a hypothesis with known multiple problems, go around promoting multiverses as a solution and as an established scientific theory to the lay public.

The third is "climate science", wherein a small group of no-rate scientists have managed to raise a weak speculative hypothesis, mostly likely nothing more than an artifact of systematic biases in data analysis and of gross underestimation of statistical and systematic uncertainties, to the level of a global quasi-religious dogma with fanatical adherents among the lay public. It is here that one encounters scientists being regarded as an infallible priesthood.



The first two sound very much like "religion" to the untrained ears attached to my untrained brain. Or perhaps, using the rock star analogy, entertainment is a better description. If I can get someone to enjoy and buy my published theories, it is identical to getting someone to enjoy and buy my songs. Income for me, entertainment for them. Whether the lyrics to my songs are fact or fiction are irrelevant to both my need for income, and their need for entertainment.

I think Michio Kaku may be one of the current rock stars. Whether he is full of it or not, I have no clue.

"Climate science" seems even worse than religion. More like Tulip bulb mania. Or doomer porn. An infinite number of data points are available, and those selected are not only correct, but represent all the rest accurately to 1/1000ths of a degree? Defies any form of reasonable belief.

How to explain the popularity? Those raised in first world countries have no concept of weather variability? Proposing that modern satellite measurements (modern faith) correspond accurately to tree ring data and ice cores? Ignoring data that does not fit the hypothesis.

To me it seems more like confessing First World Guilt buys one a seat at the Compassionate lunch table on one hand, a simple quest for money and power on the other hand.

Similarities to buying dispensations is staggering. Living on earth is original sin.... luckily, we have the cure.
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Re: Quantum weirdness

Postby Typhoon » Sun Jan 03, 2016 7:42 am

Simple Minded wrote:
noddy wrote:
Simple Minded wrote:
these types of replies kinda make me feel sorry for Typhoon as a moderator. PhD's must get lonely for intelligent, adult conversation at times.....


thats what talking to yourself is for.


also splains the fondness for girly pics.


Perhaps, but then how does one explain that the number of views for the girly pics thread greatly exceeds that of all other threads? :wink:
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Re: Quantum weirdness

Postby Simple Minded » Sun Jan 03, 2016 2:01 pm

Typhoon wrote:
Simple Minded wrote:
noddy wrote:
Simple Minded wrote:
these types of replies kinda make me feel sorry for Typhoon as a moderator. PhD's must get lonely for intelligent, adult conversation at times.....


thats what talking to yourself is for.


also splains the fondness for girly pics.


Perhaps, but then how does one explain that the number of views for the girly pics thread greatly exceeds that of all other threads? :wink:


either you have good taste, or all OTNOTer's are closet scientists with PhD's......... probably the former. ;)
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Re: Quantum weirdness

Postby Typhoon » Sun Jan 03, 2016 6:37 pm

Simple Minded wrote:
Typhoon wrote:
Simple Minded wrote:
noddy wrote:
Simple Minded wrote:
these types of replies kinda make me feel sorry for Typhoon as a moderator. PhD's must get lonely for intelligent, adult conversation at times.....


thats what talking to yourself is for.


also splains the fondness for girly pics.


Perhaps, but then how does one explain that the number of views for the girly pics thread greatly exceeds that of all other threads? :wink:


either you have good taste, or all OTNOTer's are closet scientists with PhD's......... probably the former. ;)


A third and simpler explanation: most of the viewers are guys.

Fortunately, a Ph.D. is not required. At least not yet . . .

Occam's Razor :wink:
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Re: Quantum weirdness

Postby Simple Minded » Mon Jan 04, 2016 11:46 am

Typhoon wrote:
A third and simpler explanation: most of the viewers are guys.

Fortunately, a Ph.D. is not required. At least not yet . . .

Occam's Razor :wink:


No doubt also true. But you are being too modest. :)

speaking of how quantum weirdness interfaces (yep, there's a pun in there) with pictures of hot women.......

http://www.news.com.au/lifestyle/relati ... 9244937207

I thought the internet was just one big virtual penis..... or maybe penii

HP, nother reason why ME people emigrate to the west.... :P

noddy, why do Stralians always break all the important news stories....
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Re: Quantum weirdness

Postby Typhoon » Mon Jan 04, 2016 2:40 pm

Parodite wrote:
Typhoon wrote:As for QM, it has passed all precision experimental tests to date.
The rival local reality theories have not, and can thus be ruled out, and no one has proposed, despite nearly a century of criticisms, another viable alternative theory to QM. So until someone does, I'll stick with QM and leave the supposed philosophical questions and objections to others.


You misrepresent, and keep misrepresenting the controversy. No one tries to dispose of QM. Some physicists are not totally happy with qm because they feel it lacks ontological relevance. Or that it still not meshes well with macro physics and gravity. I'm just trying to figure out about the alleged quantum weirdness, what it is about and what not. A lot of smoke and mirrors there.


You're right that there is a lot of smoke and mirrors out there in that what you call "quantum weirdness" has attracted far more than it's fair share of crackpots on the internet promoting not-even-wrong expositions.

In macrophysics, quantum coherence is typically destroyed by the many-particle random position - momentum due to heat. The transitions to superconductivity and superfluidity as temperatures approach absolute zero are two examples of macroscopic quantum phenomena. I don't think that many physicists have an issue with this.

Quantum gravity is entirely another level of difficulty in that despite intense effort, since the earliest days of QM, no one has yet figured out how to properly quantize space-time.

A good lay survey of the problems and the current state-of-the-art with regards to attempts at quantum gravity:

What Are Quantum Gravity's Alternatives To String Theory?
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Re: Quantum weirdness

Postby Parodite » Thu Jan 07, 2016 10:07 am

Thank you for the links. Maybe there are also some fundamental questions left to be asked about quantization. What exactly happens when an atom jumps from one energy state to another for instance? When I walk from a > b the distance is covered in discrete steps. But jumping from one leg to another does not happen via magic steps emerging from a magical hat; there are transitions between those steps. Maybe ideas exist how this "discrete" jumping in qm occurs mathematically in an otherwise differentially calculated universe that you know of?

For us laymen I found those two excellent videos that go back to basics first and with historical background.





Looking forward to the 3rd forthcoming on qm and its friggin' weirdness.
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Re: Quantum weirdness

Postby Typhoon » Fri Jan 08, 2016 3:25 pm

Parodite wrote:Thank you for the links. Maybe there are also some fundamental questions left to be asked about quantization. What exactly happens when an atom jumps from one energy state to another for instance? When I walk from a > b the distance is covered in discrete steps. But jumping from one leg to another does not happen via magic steps emerging from a magical hat; there are transitions between those steps. Maybe ideas exist how this "discrete" jumping in qm occurs mathematically in an otherwise differentially calculated universe that you know of?

. . .


I think you're trying to relate everyday experience to QM.

The two are fundamentally different.

A lot of clever people have spent a lot of time trying to come up with a supposedly more fundamental "gears, levers, and wheels" underlying mechanism for QM. Zero successful results to-date.

All evidence to-date is that QM is the fundamental description of nature.

Note that QM describes how, energy eigenstates in your example above, not why. This is physics in general.

In QM, one sets up and solves the time-independent Hamiltonian* to get the energy eigenstates of the system, for example, the hydrogen atom.

That's it.

Transition between energy states is by the aborption or emission of a quantum of energy - a photon of light:

Image

[The first three spectra are the emission spectra of excited gases of hydrogen (H), mercury (Hg), and neon (Ne), respectively.
The bottom spectrum is the absorption spectrum of hydrogen.]

*Hamiltonian mechanics
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Re: Quantum weirdness

Postby Parodite » Sun Jan 10, 2016 12:21 pm

Typhoon wrote:
Parodite wrote:Thank you for the links. Maybe there are also some fundamental questions left to be asked about quantization. What exactly happens when an atom jumps from one energy state to another for instance? When I walk from a > b the distance is covered in discrete steps. But jumping from one leg to another does not happen via magic steps emerging from a magical hat; there are transitions between those steps. Maybe ideas exist how this "discrete" jumping in qm occurs mathematically in an otherwise deferentially calculated universe that you know of?

. . .


I think you're trying to relate everyday experience to QM.

The two are fundamentally different.


I expect that to be the case but am not there yet. Right now I'm cutting my way through loads of "not even wrong" nonsense, language abuse and PR of snake oil salesmen who sell QM as one would try to sell a magicians toolbox and manual. "A particle that can be a two places at the same time! A dickhead that goes through two sl*ts at the same time and interferes with itself! Come and see the magic!" 8-) (I understand.. they need funding too and want to raise public interest in their work)

Probably I end up in the agnostic church of Feynman... where simply no ontological claim is made about things unknown, unobserved/measured. But as a physicist there was no doubt in his mind: QM is very weird. Don't even try to make sense of it. But I defy my own expectations here and assume he was mad and surrendered to this God called Unknoweability. It is a religious kinda reflex when the going gets tough. :ugeek: (perhaps even a Jewish thing)

A lot of clever people have spent a lot of time trying to come up with a supposedly more fundamental "gears, levers, and wheels" underlying mechanism for QM. Zero successful results to-date.


I know. But it isn't clear to me so can't subscribe to that. Mechanics is supposed to be about gears, levers. and wheels. QM is also and still full of them. The particle-like behavior as observed in qm experiments for instance. Even the double-slit experiment is a purely mechanical event with causes and effects. They may not be totally understood but that doesn't make things necessarily weird or different from the usual gears, levels and wheels models that rule most of physics even today.

All evidence to-date is that QM is the fundamental description of nature.


But there is no gravity and general relativity in QM as of yet.

Note that QM describes how, energy eigenstates in your example above, not why. This is physics in general.


Progress starts with a why-question and then through observation, theory and experiment a how-answer emerges when results can be reproduced under controlled conditions. Then how-answers usually give rise to new why-questions and so science rolls forward. Why is the buck stopping at the eigenstates and no further why allowed or possible?

This is one of the things that intrigues me and for which there may be an answer: is there a "look no further beyond QM" because 1) in QM we have reached a practical limit to investigate these matters any further, 2) from QM theory and all experiment it follows naturally there simply isn't anything above or beyond the QM model possible; no hidden variables (local nor non-local), or other known and unknown unknowns are feasible. Usually one encounters the latter claim: but I haven't found the rationale or proof for that.

A physicist once explained it like this, as I remember it: In theory it is always possible that there is more physics involved in QM that we are not aware of but nothing to date points to what that could or should be. QM works and predicts fine without the need to add or remove anything.

I would think that in any case there is a practical limit to investigate the nature of very small systems and to how bigger systems behave as multi-particle quantum systems. But if an ontological statement can be made that the qm description is fundamental and complete... that is a bridge too far. Also given the problems of QM with gravity and general relativity.

It seems safer to assume that all theory and practice, also QM, are approximations within a limited domain of validity. I'm skeptical a theory of everything will ever be "complete" enough to satisfy everybody. The eternal "why" will always peep through the cracks.

In QM, one sets up and solves the time-independent Hamiltonian* to get the energy eigenstates of the system, for example, the hydrogen atom.

That's it.

Transition between energy states is by the absorption or emission of a quantum of energy - a photon of light:

Image

[The first three spectra are the emission spectra of excited gases of hydrogen (H), mercury (Hg), and neon (Ne), respectively.
The bottom spectrum is the absorption spectrum of hydrogen.]

*Hamiltonian mechanics


Yes, this is also explained in the two videos I posted on QM made easy.
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Re: Quantum weirdness

Postby Typhoon » Tue Mar 15, 2016 6:49 pm

A excellent lay review of QM:

Forbes - "Bee" | 10 Quantum Truths About Our Universe

Appreciation to Forbes for publishing this level of article.
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Re: Quantum weirdness

Postby Parodite » Fri Feb 24, 2017 1:19 am

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Re: Quantum weirdness

Postby Typhoon » Fri Feb 24, 2017 6:33 am

Parodite wrote:


QM is a strictly linear theory with the all important principle of linear superposition of states.

The experiment, extrapolated as a model for the pilot wave theory, is governed by the highly non-linear equations of fluid dynamics.

So, no.
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Re: Quantum weirdness

Postby Parodite » Tue Feb 28, 2017 7:44 pm

Typhoon wrote: QM is a strictly linear theory with the all important principle of superposition.


I think the video tries to make possible physical sense of superposition beyond the mathematical formalism. Superposition and collapse of the wave function are mathematical descriptions, what they mean/represent physically is open for debate and a controversy still.

The Trouble with Quantum Mechanics - Steven Weinberg

I like the Feynman approach to safely remain agnostic about the physical reality of things before a quantum measurement. Is a "wave-particle in a superposition when all possible states (outcomes) exist at the same time?" Makes no linguistic sense.

Claims about the un-observed are not helpful it seems to me. I prefer terms like "unknown" "undecided" and leave it at that. So a legit phrase would be: the mathematical formalisms and their proven reliability to predict and be applied in technology, suggest that before a quantum measurement (mathematically: the collapse of the wave function), it is as-if a wave-particle exists in a superposition of all possible outcomes "at the same time". With the emphasis on as-if. Same with non-locality claims: as-if a particle can be at two different places at the same time.

The experiment is governed by non-linear equations.


You mean the experiment in the video?

Not sure this is relevant: harmonic oscillations in classical physics yield linearity. In the video the wave that goes with the bouncing particle is a standing wave.

https://www.youtube.com/watch?v=qu-jyrwW6hw

and

http://www.ks.uiuc.edu/Services/Class/P ... F/chp4.pdf
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Re: Quantum weirdness

Postby Typhoon » Wed Mar 01, 2017 11:49 pm

Parodite wrote:
Typhoon wrote: QM is a strictly linear theory with the all important principle of superposition.


I think the video tries to make possible physical sense of superposition beyond the mathematical formalism. Superposition and collapse of the wave function are mathematical descriptions, what they mean/represent physically is open for debate and a controversy still.

The Trouble with Quantum Mechanics - Steven Weinberg



Lots of very bright people are uncomfortable with QM.

None as yet have come up with a viable testable alternative.

Parodite wrote:I like the Feynman approach to safely remain agnostic about the physical reality of things before a quantum measurement. Is a "wave-particle in a superposition when all possible states (outcomes) exist at the same time?" Makes no linguistic sense.


That is a limit of language, not of nature.

Parodite wrote:Claims about the un-observed are not helpful it seems to me. I prefer terms like "unknown" "undecided" and leave it at that. So a legit phrase would be: the mathematical formalisms and their proven reliability to predict and be applied in technology, suggest that before a quantum measurement (mathematically: the collapse of the wave function), it is as-if a wave-particle exists in a superposition of all possible outcomes "at the same time". With the emphasis on as-if. Same with non-locality claims: as-if a particle can be at two different places at the same time.


I don't worry much about the linguistics, as mathematics is the language of nature.

Parodite wrote:
The experiment is governed by non-linear equations.


You mean the experiment in the video?



Yes.

Parodite wrote:Not sure this is relevant: harmonic oscillations in classical physics yield linearity.


No. The solution of the linear Schrodinger equation with a quadratic restoring potential yields a quantized harmonic oscillator.

Parodite wrote:In the video the wave that goes with the bouncing particle is a standing wave.




Lovely. Except that no one has come up with a underlying medium, such as water, that would act as a "pilot wave" to "guide" an electron.

Reminds one of the luminiferous aether hypothesis of the late 19th century that was thought to be necessary for the propagation of light.

Analogies can only take one so far.

There are further issues. QM based on the Schrodinger equation is only an approximation and is incomplete.

One has to reconcile QM with the constraints of special relativity:

The consequences of relativistic QM [RQM], the Dirac equation, are the existence of antimatter and the spin of the electron [and positron].

As far as I'm aware, no one has successfully written down a RQM for the de Broglie-Bohm pilot wave hypothesis.

However, this is not the end of the story, by any means.

For example, RQM comes close to predicting the correct difference between the 2S 1/2 and 2P 1/2 energy levels of the hydrogen atom and the magnetic moment of the electron, but not close enough. RQM it turns out, is only another higher level of approximation.

To achieve agreement between theory and experiment required the development of quantum field theory [QFT for the EM field, quantum electrodynamics - QED, by Schwinger, Tomonaga, Feynman, and Dyson].

[Aside. The history of this heroic intellectual effort is documented here:

https://www.amazon.com/Selected-Papers- ... +schwinger ]

QFT is required to described the fundamental EM and weak and strong nuclear forces in nature.

As far as I'm aware, no one has successfully written down a QFT for the de Broglie-Bohm pilot wave hypothesis.

QFT is the required description of fundamental quantum processes in nature.



If you wish to learn QM, then I can suggest no better source than

QM; Vols 1 and 2

by Cohen-Tannoudji, Diu, and Laloe

https://www.amazon.com/Quantum-Mechanic ... 047116433X

The chapter on the quantization of the harmonic oscillator is classic.

Although the MIT OpenCourse is also certainly worth viewing.

Btw, the quantum harmonic oscillator (QHO) and the ladder operator formalism of Dirac
are fundamental to the development of quantum field theory.

For example, the excitations of the EM field correspond to the energy levels of the QHO.
The ladder operators become the field creation - annihilation operators.
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Re: Quantum weirdness

Postby Parodite » Sat Mar 04, 2017 3:52 pm

Typhoon wrote:
Parodite wrote:I like the Feynman approach to safely remain agnostic about the physical reality of things before a quantum measurement. Is a "wave-particle in a superposition when all possible states (outcomes) exist at the same time?" Makes no linguistic sense.


That is a limit of language, not of nature.


Of course. But this limit is often not taken into account when people with supposed authority talk about QM are actually selling bad poetry to the public instead of physics. Bad language has inspired many gullibles to go on a spiritual ride with the magic of quantum mechanics making claims about human consciousness for which there is no coherent argument let alone experimental evidence.

Parodite wrote:Claims about the un-observed are not helpful it seems to me. I prefer terms like "unknown" "undecided" and leave it at that. So a legit phrase would be: the mathematical formalisms and their proven reliability to predict and be applied in technology, suggest that before a quantum measurement (mathematically: the collapse of the wave function), it is as-if a wave-particle exists in a superposition of all possible outcomes "at the same time". With the emphasis on as-if. Same with non-locality claims: as-if a particle can be at two different places at the same time.


I don't worry much about the linguistics, as mathematics is the language of nature.


I would call math the grammar of nature, and nature being multilingual. Even so, part of what physicists do, as opposed to pure mathematicians, is wonder ponder who/what is doing the talking. Sort of analogous to a Turing test.

Parodite wrote:In the video the wave that goes with the bouncing particle is a standing wave.


[youtube]...[/youtube]

Lovely. Except that no one has come up with a underlying medium, such as water, that would act as a "pilot wave" to "guide" an electron.


I'm happy to leave that to physicists who feel the need to prove such a thing. :)

Reminds one of the luminiferous aether hypothesis of the late 19th century that was thought to be necessary for the propagation of light.


But such an "aether" as a concept is qualitatively not much different from something mysterious like "a force field". What is a force field in "empty space"?

The "aether" seems to me more like a provisional soundbite that points to the idea that "nothingness" in regions of space-time cannot be considered empty in a literal sense. Another way of saying that one can safely assume that physical reality is indivisible. That whatever objects, forces, fields we identify.. they cannot be considered to co-exists in pure isolation interacting via something like a medium of pure nothingness. What "glues" everything together turning the sum of parts into an indivisible whole? My 2 cents: we won't find that glue.

Analogies can only take one so far.


Indeed. But analogy and contrast have always been great tools for discovery.

There are further issues. QM based on the Schrodinger equation is only an approximation and is incomplete.

One has to reconcile QM with the constraints of special relativity:

The consequences of relativistic QM [RQM], the Dirac equation, are the existence of antimatter and the spin of the electron [and positron].

As far as I'm aware, no one has successfully written down a RQM for the de Broglie-Bohm pilot wave hypothesis.

However, this is not the end of the story, by any means.

For example, RQM comes close to predicting the correct difference between the 2S 1/2 and 2P 1/2 energy levels of the hydrogen atom and the magnetic moment of the electron, but not close enough. RQM it turns out, is only another higher level of approximation.

To achieve agreement between theory and experiment required the development of quantum field theory [QFT for the EM field, quantum electrodynamics - QED, by Schwinger, Tomonaga, Feynman, and Dyson].

[Aside. The history of this heroic intellectual effort is documented here:

https://www.amazon.com/Selected-Papers- ... +schwinger ]

QFT is required to described the fundamental EM and weak and strong nuclear forces in nature.

As far as I'm aware, no one has successfully written down a QFT for the de Broglie-Bohm pilot wave hypothesis.

QFT is the required description of fundamental quantum processes in nature.


Interesting. Maybe big-bang (or big bounce) physics could give clues to that? After all.. from that point 13.6 billions years ago nature/cosmos evolved to what it is now. Just my 2 cents.



If you wish to learn QM, then I can suggest no better source than

QM; Vols 1 and 2

by Cohen-Tannoudji, Diu, and Laloe

https://www.amazon.com/Quantum-Mechanic ... 047116433X

The chapter on the quantization of the harmonic oscillator is classic.

Although the MIT OpenCourse is also certainly worth viewing.

Btw, the quantum harmonic oscillator (QHO) and the ladder operator formalism of Dirac
are fundamental to the development of quantum field theory.

For example, the excitations of the EM field correspond to the energy levels of the QHO.
The ladder operators become the field creation - annihilation operators.


Thanks.

Forgot which discovery, but something when Einstein (i think) added a provisional glitch in his equations to get a solution.. and later this glitch turned out to be a famous constant. Going back and forth between the math of physics and experimentation/observation, sometimes observe things that don't fit the math yet or vice-versa making the math fit and then hunt for the potential thing missing in the physical world, must be very rewarding! In my next life I want to have a wee bit more talent for math though. The probability distribution for that to happen is unknown unfortunately. Maybe it is in the aether.
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