Author Topic: quantum mechanics  (Read 1190 times)

shankle

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quantum mechanics
« on: December 20, 2016, 11:19:33 PM »
                 12-20-2016

    I am not a physicist.
   My knowledge of quantum mechanics is zero.
    I watched a program on TV that was hosted by a physicist.
   He discussed 3 subjects one of which was an argument that
   Norweigen Bohr and Einstein had on light theory.
   Another was a test of quantum mechanics. He placed two blocks
   of wood about 1 foot apart. Then he spun two quarters at the
   same time and stopped the 1st quarter with his hand and the
   2nd quarter with his hand a second later. He did this about 6
   times. All six times the quarters were heads and tails. Never
   two heads or two tails.
   An example in Bridge makes me wonder about the above result.
   There are 13 spades in a deck of cards. My partner bids 1 spade.
   This means he has 5 spades and if I have 3 spades I bid two spades.
   Now we know the opponents have 5 spades. 66% of the time they
   divide 3/2.   4/1 and 5/0 are rare.
   I didn't hear a clear explanation of the spinning coins result
   and as far as I could tell it has something to do with quantum
   mechanics.
   Your thoughts please.
            

jimg

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Re: quantum mechanics
« Reply #1 on: December 21, 2016, 02:07:07 AM »
Sounds like nonsense to me.   

From experience, the spades will usually be split 1-4, regardless what the odd say.

As computer programming experts, we know what round off error is.  You can only represent accuracy to the number of bits you have to work with.  It seems to me that the effects scientists "observe" with quantum mechanics, etc.  are just do to roundoff error in our reality.  After all, the whole subject is based upon quanta, or units.  There are minimum units of length, time, mass, etc.  They are mistaking the effects they are seeing as real when in actuality, it is just the difference of one bit change in reality.

We all know here in the matrix, that everything is just a simulation on a computer.

GoneFishing

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Re: quantum mechanics
« Reply #2 on: December 21, 2016, 05:02:29 AM »
...
We all know here in the matrix, that everything is just a simulation on a computer.

If so , where is the One who knows how to control that "everything" ?

rrr314159

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Re: quantum mechanics
« Reply #3 on: December 21, 2016, 12:52:03 PM »
@shankle, The spinning coins illustrate entanglement, I suppose. When two particles are entangled with opposite spins, if one is spin up the other must be spin down. But each, considered individually, seems in all respects perfectly random, like the tossed quarters.

I can answer any question you might have about this topic, assuming I'm in the mood.

@jimg, yes "round-off error" is a good candidate for a partial explanation of QM. Of course it's more complicated than that, but you can in fact explain Planck's quantum of action along those lines.

I don't know if reality is a computer simulation, nor do I expect we'll ever know. But it's a very good and fruitful explanation. In about 20 years, I reckon, it will become the dominant paradigm in physics. We have to wait for the current generation to die off. BTW I was pushing it enthusiastically 20 years ago - 40 years too soon.

@GoneFishing, if it's a simulation then Who's the programmer?? It's better to ignore that question, the topic is controversial enough as it is.
I am NaN ;)

GoneFishing

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Re: quantum mechanics
« Reply #4 on: December 21, 2016, 09:21:08 PM »
...
@GoneFishing, if it's a simulation then Who's the programmer?? It's better to ignore that question, the topic is controversial enough as it is.
It's easy - TrustedInstaller  :biggrin: He always comes at night ...   :redface:

BTW For a programmer It's a natural way of thinking about the universe as a huge sandbox, virtual machine, game etc.

Imagine if you were    an architect    or    beekeeper    or carpenter    or doctor  -
How would you think about the universe , its goal and creator ?     

hutch--

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Re: quantum mechanics
« Reply #5 on: December 22, 2016, 10:09:48 PM »
There is always a solution to rounding, instead of decimal or even computer 0/1, we all (if you are old enough) learnt fractions at school and one third x 3 still makes 1 without any rounding error. Computer calculate in powers of 2, humans have 10 fingers and neither have the precision of fractions.
hutch at movsd dot com
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rrr314159

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Re: quantum mechanics
« Reply #6 on: December 23, 2016, 03:02:37 PM »
Sure, you can eschew floating point and use fractions (rational numbers), keeping track of numerator and denominator as (relatively prime) integers. But, assuming there's a limit to the size of the integers, you'll still run into rounding error sooner or later.

In fact the correct analogy to Planck's constant is the time slice granularity of a presumed time-share simulator. Or, simplest possible analogy, the granularity could be a single instruction. That, and many other details, I didn't bother to discuss, assuming no one's interested.
I am NaN ;)

shankle

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Re: quantum mechanics
« Reply #7 on: December 24, 2016, 02:03:45 AM »
It's not that I am not interested but most of these explanations are
way out of my purview.

The comment about the Bridge percentage is not correct. Bridge experts(not me)
have decided that the 3/2 split will occur 66% of the time. 1/4 or 5.0 is rare.

I reference  to what Nan said "spinning coins in opposite directions". Would spinning
them in the same direction make any difference? 

FORTRANS

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Re: quantum mechanics
« Reply #8 on: December 24, 2016, 05:20:18 AM »
Hi,

   In most explanations of entanglement, you start with a {something}
with no spin that decays into two like particles with spin.  To conserve
spin, one must be spinning in a direction opposite of the other.  Note
that "spin" is a different phenomenon for quantum particles than for
macroscopic objects.

   If you found a way to guarantee that two particles had identical spins,
then they could spin in the same direction.  But that does not seem
easy to do in the common explanations of entanglement.  Particles
with spin two are gravitons in most theories.  No one has yet seen
one, much less have it decay into two like, stable, spin one particles.

   I think photons might be used in that way, but memory is fuzzy
with the holidays.  I will let you do the search on that subject.

Happy holidays,

Steve

rrr314159

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Re: quantum mechanics
« Reply #9 on: December 24, 2016, 07:57:18 AM »
shankle>> It's not that I am not interested but most of these explanations are way out of my purview.

I'm particularly useful for vague "intelligent layman"-type questions. When I said I could answer any question "you" had, I meant you specifically - not an expert. 45 years ago I was Ok with advanced math questions also, but it's been a long time since I could pass my orals. This is your opportunity to ask the type of question which "real" experts sneer at. They're usually lousy at explaining things to laymen, because they don't really understand it. They just learned to manipulate the equations and solve them by rote - like me, 45 years ago.

shankle>> The comment about the Bridge percentage is not correct. Bridge experts(not me) have decided that the 3/2 split will occur 66% of the time. 1/4 or 5.0 is rare.

This is a simple application of binomial theorem - Pascal's triangle. The number of ways to make the possible distributions are 1, 5, 10, 10, 5, 1 (you probably recognize that sequence). So chance of 3-2 is 20/32 = 5/8 = 62.5%; 4-1 = 5/16, 5-0 = 1/16.

I guess it's possible, nevertheless, that @jimg is right. Maybe in practice it often comes out 1-4. Here's a possible explanation. That split is better for your opponents than 3/2, obviously. The guy holding 4 spades is more likely to let you have your spades. Thus in practice - when you actually play it out - wouldn't be surprised if your opponents are split 1-4, more often than one would suppose from the stats.

shankle>> I reference  to what Nan said "spinning coins in opposite directions". Would spinning them in the same direction make any difference?

The coins are only an analogy or illustration of spins entangled opposite (Bell state psi+, or psi-). Spinning them in opposite directions, or not, doesn't matter. I didn't say anything about it, some misunderstanding there. BTW I'm not "Nan", but rrr314159 - NaN means "Not a Number", the tag line is a reference to "The Prisoner" with Patrick McGoohan :-)

@FORTRANS, there's some confusion here. @shankle is talking about opposite "spin" directions, or not, in the coin analogy. You're talking about opposite spins, or not, in actual QM experiment.

You're right, most QM experiments and gedankens use spin-0 decay to generate two fermions with opposite spins, +-1/2 hbar; or photons with opposite polarizations. But it's very easy to consider spins in the same direction. For one thing a photon of energy >= 1.022 MeV can produce electron-positron each with positive spin 1/2 (or, both negative). But the easiest way is to simply invert one detector 180 degrees! May seem like cheating but it's perfectly legitimate. In this way we can talk about the Bell state phi+ (or psi-, entangled spins in same direction) instead which is simpler conceptually. Also of course with a quantum computer we can create any Bell state as easily as another.
I am NaN ;)