Quantum Mechanics - for those looking to take the next step

[Bad Hussar]

The craziest Quantum Mechanics experiment I've seen recently is the Delayed Choice Quantum Eraser. It takes things a step further from the normal double split proving that the detection device isn't what's causing the waveform to collapse. If there is "information" available about which slit the photon passed through then we will see the recorded data show a particle. If that information is completely erased before reviewing the results then the recorded results will show the wave pattern. The existence or non-existence of the "which path" information is determining the results. If the "which path" information is later "erased" it will change the pre-recorded results to show a wave pattern. Somehow going back in time it seems.

https://www.youtube.com/watch?v=U7Z_TIw9InA

Ja. The best explanation I've heard about how this could be, strictly from "popular science" accounts, is that a pilot wave is sent out at about the speed of light, reaches it's target, and then somehow returns faster than the speed of light to the source. Travelling faster than light results in it moving back in time, and the net effect is that the particle "knows" what it will encounter as it sets off.

I'm well aware that the above paragraph is exactly what the OP is rallying against. Think the idea is from a John Gribbin book. I have no real defense. It's just that waves travelling faster than light, and therefore backward in time seems like the most elegant, and least weird, explanation for what we observe in the double slit and similar experiments.

I actually quite like mathematics, though, and have seen the Suskind book at my local bookstore. So will probably grab it later this week.

 

[TonySandos]

Mathematics > physics > engineering studies > biological studies > anthropological studies > history > philosophy > psychology > sociology

 

[Hades]

that photogenic astrophysicist black guy with no credentials to speak of.

I'm looking at a list of Tyson's research papers, and judging from the titles plenty of math is involved.

Yeah I kind of ran on with that sentence. The hipsters cherry-picking hodgepodges of bullshit had no credentials. Neil Degrasse Tyson does have credentials. He seems to contribute on a lot of research according to Wikipedia.

 

[Menace]

Neil D. Tyson is a very average astrophysicist as far as I can tell. He went to some decent institutions and published some papers, none of which are particularly earth shattering. He is probably an effective communicator, and that is laudable. But he is beloved by the losers of reddit to a point well beyond reason. I hate to say this in this thread, but really it's a form of meta racism because he's so against type. Anyway, that's neither here nor there.

 

[Wutang]

I hate the constant dick riding that surrounds NDT but at the same time I don't put the blame on him. That rests squarely on his fanboys. I don't know high level of a scientist he is but as long as he's competent I think that's enough for him to do what he does which is basically be a PR guy for science that talks to the general public. That's what he is famous and lauded for and it has to be admitted that he is effective at it.

 

[Hades]

He has published some decent papers that are worthy of his standing within the community and many of them are such that he was the primary collaborator (particularly his earlier papers in the late 80s). His research did push forward the realm of astrophysics somewhat (to the extent that all do) but yeah, his work is not earth shattering like something that Stephen Hawking came up with. There's nothing wrong with that though.

 

[Menace]

Agree on that Hades. He appears to be a competent scientist. The fault is in his fanboys.

 

[H1N1]

Cannot recommend the work of Sir Roger Penrose, who is currently the Emeritus Rouse Professor of Mathematics at Oxford, and one of the worlds leading mathematicians and theoretical physicists. I've been reading his book 'The Emperor's New Mind', regarding the possibility of Strong AI, and it is completely fascinating.

I would have to respectfully disagree with the guys here who suggest that this is a waste of time for anyone who doesn't 'need' to study it. To me, the study of maths and physics is the most essential past time for any intelligent and thoughtful man. Whether you are atheist or religious, to study maths and physics is to try to know 'God', to strive after enlightenment, or to understand the human condition.

Furthering your understanding of maths and physics furthers your understanding of yourself, the world around you, and your ability to grapple with the great mysteries of life. Satisfaction of intellectual curiosity is perhaps the defining feature of advanced intelligence, and if you are an intelligent man, what greater knowledge or understanding could you strive for than to comprehend God/the universe.

What has become clear to me, as someone who came to maths and physics late, is that maths, physics and philosophy are all inextricably linked, and that only through their dedicated study can you possibly come to understand the world around you, and grapple with the greatest questions that have faced humanity since the ancient civilizations. I do not believe there is a more noble aspiration for the human spirit that to understand complex science, and through it to hold informed beliefs on the nature of the universe, God, and life on earth.

I truly believe that we have arrived at a point in our evolution whereby philosopher, theologian, scientist and mathematician cannot be meaningfully distinct. Penrose himself, a former atheist (I believe - never met the bloke), believes that his mathematical discoveries reveal the nature of 'God' (not necessarily in the religious, bearded man sense).

Again, I have to disagree with those who would discourage the OP, and encourage all thoughtful men to throw themselves at the study of maths and physics with what might formerly have been referred to as a 'religious zeal'. Contrary to the assertion that science has been a significant driver for the modern, nihilistic world, I would suggest that real science holds the key to salvation from a meaningless, materialistic existence, and represents our greatest opportunity to find real meaning in life.

 

[Hades]

I would have to respectfully disagree with the guys here who suggest that this is a waste of time for anyone who doesn't 'need' to study it. To me, the study of maths and physics is the most essential past time for any intelligent and thoughtful man. Whether you are atheist or religious, to study maths and physics is to try to know 'God', to strive after enlightenment, or to understand the human condition.

Furthering your understanding of maths and physics furthers your understanding of yourself, the world around you, and your ability to grapple with the great mysteries of life.

I would encourage everybody to to increase their understand of maths first and physics second. I would further temper their enthusiasm by suggesting they start with the basics first and do it properly. Khan Academy will do it right. The best part is that you don't have to suffer through the material that much and grind through lots of problems.

 

[Quintus Curtius]

Great thread.

The farthest I've ever taken these studies is to read a few of those popularized books you find on the subject, of the type that you can find in bookstores or the library.

What little I do know is mind-blowing.

But I do agree with the OP that if you can understand the math of these ideas (de Broglie's wave equation, Psi functions, etc.) you will get far more out of it.

The problem is, of course, that it is very difficult to learn advanced mathematics on your own. I've never taken the time to do it, but hats off to those who do.

Maybe someone who has wrestled with these mathematical alligators can recommend some good books on these subjects; books that are rigorous enough to expose us to the hard stuff, but not so advanced to be beyond our reach.

.

 

[Wutang]

Furthering your understanding of maths and physics furthers your understanding of yourself, the world around you, and your ability to grapple with the great mysteries of life. Satisfaction of intellectual curiosity is perhaps the defining feature of advanced intelligence, and if you are an intelligent man, what greater knowledge or understanding could you strive for than to comprehend God/the universe.

What has become clear to me, as someone who came to maths and physics late, is that maths, physics and philosophy are all inextricably linked, and that only through their dedicated study can you possibly come to understand the world around you, and grapple with the greatest questions that have faced humanity since the ancient civilizations. I do not believe there is a more noble aspiration for the human spirit that to understand complex science, and through it to hold informed beliefs on the nature of the universe, God, and life on earth.

This is indeed my main reason for wanting to studying all of this. I'm very attracted to philosophy and metaphysics but I can't shake the feeling that without having more of a grounding in math/physics I'm somehow missing the entire picture. I don't intend to earn my bread from this knowledge and I don't think I have the intelligence and vision to really make any big contributions to the field but I would simply be happy just to be able to have an understanding of it.

 

[Bad Hussar]

Great thread.

The farthest I've ever taken these studies is to read a few of those popularized books you find on the subject, of the type that you can find in bookstores or the library.

What little I do know is mind-blowing.

But I do agree with the OP that if you can understand the math of these ideas (de Broglie's wave equation, Psi functions, etc.) you will get far more out of it.

The problem is, of course, that it is very difficult to learn advanced mathematics on your own. I've never taken the time to do it, but hats off to those who do.

Maybe someone who has wrestled with these mathematical alligators can recommend some good books on these subjects; books that are rigorous enough to expose us to the hard stuff, but not so advanced to be beyond our reach.

.

I'd recommend playing around with mathematics software like "Mathematica". The graphing functions are great, and allow you to visualise a problem and its solution. Men are almost universally visual, so if you can think of a problem in terms of images it helps enormously.

 

[Gamma]

Thanks for the feedback guys.

I know mathematics is a chore. And this may all feel a waste of time. But if you look at the four videos I mentioned by DrPhysicsA. That will be enough to give you a clear insight into what Quantum Mechanics is really about. In terms of the Dirac notation and mathematical modelling involved.

In terms of the basics. No complicated mathematics are involved. Just a bunch of scary looking symbols (which are easy to grasp once they are explained). At least as learning up to Hesineberg's Uncertainty Principle is concerned.

I am useless at maths - and I had no problems following those lessons. And with those four hours I felt I had finally learned more about the true nature of QM than I had from reading dozens of "popular science" books.

---------------------

Now I have got the basics out of the way with my first couple of posts - I want to move onto some really fascinating stuff.

Nick Herbert is a really interesting thinker in quantum mechanics. He wrote a great book on the subject in the 80's:

http://www.amazon.com/Quantum-Reality-Beyond-New-Physics/dp/0385235690/ref=asap_bc?ie=UTF8

He also has the simplest proof for Bell's Theorem. This is well worth checking out since it is the most elegant and important idea in all of physics:

http://quantumtantra.com/bell2.html

Anyway - an interesting thing about this remarkable man is that he proposed a faster-than-light telegraph 1981. This was a very profound idea since it basically doubles up as time machine which allows you to send messages to the past. His idea was so ingenious that even Richard Feynman could not figure out why it would not work.

You can find the details here:

http://www.scientificamerican.com/article/mistakes-faster-than-light-telegraph-that-wasnt/

Anyway - this idea caused a lot of controversy in the physics community since everyone who saw it was convinced there had to be a flaw in the idea. And there was. What is cool is that this failed thought experiment led to an important new theorem in quantum mechanics called the 'No Cloning Theorem'. You can see a simple explanation of it here. Simple that is for those of you who have followed the advice of my original post and learned a little about the Dirac notation that underpins quantum mechanics.



This 'No Cloning Theorem' also means a Star Trek style teleportation device will never be possible. Sadly. The laws of physics simply do not allow for it.

For those interested - here is another book recommendation. It is a useful book that covers a lot of the most interesting ideas in QM. Such as Bell's Theorem and the No Cloning Theorem. It is a short book and easy to read. But it covers this area in a rigorous way and touches on some of the maths as well (but in a reader friendly manner).

http://www.amazon.com/gp/product/3319054724?keywords=bells theorem&qid=1444167938&ref_=sr_1_6&sr=8-6

I will finish by talking a bit more about John Bell. He was nominated for the Nobel prize in Physics just before he died in 1990. And there is no doubt he would have eventually won a Nobel prize for his remarkable 'Bell's Theorem'.

Ever since then the word has being that the experimenters who helped prove Bell's Theorem will receive a Nobel prize in recognition for their work. And as a belated recognition of the genius of John Bell. So mark down the names of John Clauser and Alain Aspect since they are odds on favourites to win the Nobel prize for Physics one day. The work of John Bell is far too important to pass without recognition from the Nobel committee. Since it is probably the most important discovery in all of physics.

An interesting thing about Bell's Theorem is that is a 'No Go Theorem'. That means that logically it has to be correct. If you came back to Earth in a billion years time - irregardless of what else science has proved or disproved there is 100% certainty that Bell's Theorem will still hold. This is not so much a scientific theory as a mathematical proof. Which can never be proved wrong. It is a deep metaphysical truth about the true nature of reality. It is very rare that physics comes across knowledge of this sort.

The funny thing is that Bell's Theorem disproved the Hidden Variables version of QM that Albert Einstein was a believer in. And as a result - the work he devoted the last 30 years of his life to has absolutely no scientific value whatsoever. Since he was looking for a way to reconcile Hidden variables with QM. As such his work from this period can literally be burned unread since it must be wrong.

Sorry Albert!

 

[Wutang]

So turns out the OP was cardguy. No wonder - always found his threads to be very high quality.

 

[poutsara]

I truly believe that we have arrived at a point in our evolution whereby philosopher, theologian, scientist and mathematician cannot be meaningfully distinct.

agree

 

[poutsara]

So turns out the OP was cardguy. No wonder - always found his threads to be very high quality.

OP is Cardguy? I was actually liking this thread.