Quantum Theory in 10 minutes

[ch3mist]

The shortest summary of quantum mechanical reality I know of would be this: The dimensionality of the wave packet is not always negligible, although it often is.

[The Good Reverend Roger]

The shortest summary of quantum mechanical reality I know of would be this: The dimensionality of the wave packet is not always negligible, although it often is.

Filthy heathen.  Quantum mechanics is when God cheats. 

And an excuse for physicists to kill cats.  Like they needed one.

[Freeky]

The shortest summary of quantum mechanical reality I know of would be this: The dimensionality of the wave packet is not always negligible, although it often is.

That's not a summary, that's someone pretending they know what the hell they're talking about by using big words they found in some book.

[LMNO]

The shortest summary of quantum mechanical reality I know of would be this: The dimensionality of the wave packet is not always negligible, although it often is.

Wrong.  The shortest summary of quantum mechanical reality is:


"When shit gets really small, shit gets really weird."

[ch3mist]

The shortest summary of quantum mechanical reality I know of would be this: The dimensionality of the wave packet is not always negligible, although it often is.

That's not a summary, that's someone pretending they know what the hell they're talking about by using big words they found in some book.

Someone's in a mood...

Yes, that is a summary of how quantum mechanics relates to the reality we perceive. When the dimensionality of the wave packet is negligible you get the special case of quantum mechanics known as classical mechanics... Or as LMNO just stated:

"When shit gets really small, shit gets really weird."

[LMNO]

Yes, that is a summary of how quantum mechanics relates to the reality we perceive. When the dimensionality of the wave packet is negligible you get the special case of quantum mechanics known as classical mechanics... Or as LMNO just stated:

Hold on... You're saying that as if there are two separate mechanics.  There aren't. There is only QM.  That is the only level of reality.  All others are approximations brought on by the limitations of our own perceptions.  In other words, the "dimensionality of the wave packet" is never negligible.  You just can't tell the difference.


Don't personalize QM.  It doesn't care.

[Triple Zero]

I think he wanted to say "when wavepacket-blah is negligible, classical mechanics is a sufficient description [in the context where the wave-blah is negligible]"

[LMNO]

Yeah, that works.  But now I'm realizing that his definition doesn't suit the purpose of explaining QM; it explains when NM (Newtonian Mechanics) can be substituted for QM.

Another semi-snarky but completely true definition: "QM is non-intuitive."

[ch3mist]

Yes, that is a summary of how quantum mechanics relates to the reality we perceive. When the dimensionality of the wave packet is negligible you get the special case of quantum mechanics known as classical mechanics... Or as LMNO just stated:

Hold on... You're saying that as if there are two separate mechanics.  There aren't. There is only QM.  That is the only level of reality.  All others are approximations brought on by the limitations of our own perceptions.  In other words, the "dimensionality of the wave packet" is never negligible.  You just can't tell the difference.


Don't personalize QM.  It doesn't care.

It seems like one hell of an assumption to claim that anything is "the only level of reality." Prior to the 1900's Newtonian mechanics was considered a complete description. QM showed that this classical mechanics was only a special case of a more complete description. Why assume that QM is complete when it could just as likely be another special case of an even more complete description?

QM accurately describes phenomena that the classic mechanics fails to describe. Before the atomic revolution we simply lacked the ability to observe such phenomena and thus failed to recognize the failings of our physics. As we continue to observe more and more fundamental levels of reality we may well begin to observe phenomena that QM in its current state fails to accurately describe.

[LMNO]

Well, you can certainly say that QM may not be the final level of reality, but it's the most fundamental we know of right now.

And the most fundamental level is the level that "is" reality.  NM has been found to be incomplete, and therefore not what reality "is". 

Reality doesn't exist on multiple levels.  It exists on one level. 

This might help explain what I'm talking about, especially this, and specifically this:

The classical world is strictly implicit in the quantum world, but seeing from a classical perspective makes everything bigger and more complicated.  Everyday life is a higher level of organization, like molecules versus quarks - huge catalogue of molecules, six quarks...I am going to talk as if the quantum world is the really real and the classical world something far away.  Not just because that makes it easier to be a native of a quantum universe, but because, at a core level, it's the truth... I am going to take a strictly realist perspective on quantum mechanics - the quantum world is really out there, our equations describe the territory and not our maps of it, and the classical world only exists implicitly within the quantum one.

[The Good Reverend Roger]

Oh, the ownage.

[Freeky]

Someone's in a mood...

Someone's setting themselves up for a shitty time here at PD...

[Triple Zero]

he really does sound like another Requia ...

hey ch3mist, if you want to stick around here, try less of the pedantry. I already believe you're smart. Ish. No need for it.

[Mesozoic Mister Nigel]

Someone's in a mood...

Someone's given me just about all the data I need to conclude he's a misogynistic little prick.

[Jasper]

I like model dependent realism.