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(Medium)   Reconciling quantum theory and cosmology is a 20th century problem that has lingered into the 21st century. Now one physicist thinks he knows why quantum effects vanish on macroscopic scales   (medium.com) divider line 93
    More: Interesting, quantum mechanics, space-time, quantum, universe, quantum superposition, self-energy, superposition principles, Roger Penrose  
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5043 clicks; posted to Geek » on 02 Jan 2014 at 2:51 PM (37 weeks ago)   |  Favorite    |   share:  Share on Twitter share via Email Share on Facebook   more»



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2014-01-02 02:47:10 PM
Visual depiction of me trying to understand that:

upload.wikimedia.org
 
ZAZ [TotalFark]
2014-01-02 02:52:38 PM
I need to think about this more.

The "big rip" conjecture says the expansion of the universe will affect smaller and smaller scales. Either that is false, or the 60 meter limit is just the value at this instant, and it will get smaller. I do like the idea of living in a 60 meter wide universe, insulated from the storm around. Kind of like the end of the Cities in Flight SF series where our heroes go off alone into micro-universes.
 
2014-01-02 02:55:11 PM

Three Crooked Squirrels: Visual depiction of me trying to understand that:

[upload.wikimedia.org image 265x240]


Visual depiction of me reading that:

i1214.photobucket.com
 
2014-01-02 02:58:42 PM
Purely theoretical at this time, as the article states, but would be interesting to devise an experiment around.

(And watch several theoretical physicists' heads asplode, regardless of the outcome.)
 
2014-01-02 03:00:19 PM
Um, it's not actually that complex, the effects do persist at the macro level, they just don't scale as hard as what we regard as 'classical' effects once you get above a certain length scale.

The same effect occurs with classical physics becoming... different at different scales.  Look at gas behavior, look at it a particle at a time and it's completely classical, shove it up to dealing with trillions of particles and you get pressure as a governing force.
 
2014-01-02 03:00:21 PM
One idea put forward by physicists such as Roger Penrose is that the influence of gravity at macroscopic scales acts like a measurement causing a quantum superposition to collapse into a single observable state.

"Gravity is the universe observing itself into reality," said the physicist after ripping a hit on his bong.
 
2014-01-02 03:07:09 PM

Barry Lyndon's Annuity Cheque: One idea put forward by physicists such as Roger Penrose is that the influence of gravity at macroscopic scales acts like a measurement causing a quantum superposition to collapse into a single observable state.

"Gravity is the universe observing itself into reality," said the physicist after ripping a hit on his bong.


As a guy on acid in college told me, "It's all just a spiral, man.  Can't you see them?  The whole universe is spirals, man."
 
2014-01-02 03:09:56 PM

FitzShivering: Barry Lyndon's Annuity Cheque: One idea put forward by physicists such as Roger Penrose is that the influence of gravity at macroscopic scales acts like a measurement causing a quantum superposition to collapse into a single observable state.

"Gravity is the universe observing itself into reality," said the physicist after ripping a hit on his bong.

As a guy on acid in college told me, "It's all just a spiral, man.  Can't you see them?  The whole universe is spirals, man."


The guy on Bath Salts just tried to eat my face.
 
2014-01-02 03:12:57 PM
weminoredinfilm.files.wordpress.com
 
2014-01-02 03:16:42 PM

FitzShivering: As a guy on acid in college told me, "It's all just a spiral, man. Can't you see them? The whole universe is spirals, man."


You could probably make a decent drinking game out of "Is this a quote from a physicist or a really high college kid?"
 
2014-01-02 03:17:21 PM

FitzShivering: Barry Lyndon's Annuity Cheque: One idea put forward by physicists such as Roger Penrose is that the influence of gravity at macroscopic scales acts like a measurement causing a quantum superposition to collapse into a single observable state.

"Gravity is the universe observing itself into reality," said the physicist after ripping a hit on his bong.

As a guy on acid in college told me, "It's all just a spiral, man.  Can't you see them?  The whole universe is spirals, man."


4.bp.blogspot.com
Agrees.
 
2014-01-02 03:19:34 PM

FitzShivering: Barry Lyndon's Annuity Cheque: One idea put forward by physicists such as Roger Penrose is that the influence of gravity at macroscopic scales acts like a measurement causing a quantum superposition to collapse into a single observable state.

"Gravity is the universe observing itself into reality," said the physicist after ripping a hit on his bong.

As a guy on acid in college told me, "It's all just a spiral, man.  Can't you see them?  The whole universe is spirals, man."


We'll ride the spiral to the end and may just go where no one's been.

/spiral out
 
2014-01-02 03:20:12 PM
TFA: In other words, every galaxy in the cosmos is accelerating away from us.

2/10
 
2014-01-02 03:21:37 PM
So is the farking cat dead or not?
 
2014-01-02 03:24:15 PM

BigLuca: So is the farking cat dead or not?


It's dead, Jim.
 
2014-01-02 03:24:24 PM
The paper doesn't seem to involve any "math" (gauge fields, spacetime tensors, etc.)

This is its summary picture:
arxiver.files.wordpress.com
 
2014-01-02 03:28:06 PM
OK, so I have a bit of an issue with how they phrased things in this article.  Specifically, the 60m. What does this 60m limit refer to? Is it an absolute point of reference, ie the Earth will end up in 60m chunks due to expansion (if there is nothing that reduces it smaller first? Or is it that if there is another observable particle within 60m then expansion can't occur? In which case the Earth itself is not subject to inflation, though empty spaces around it would be, if there is no stuff we can measure there?

For example, galaxies appear to be redshifted away because there are gaps more than 60m between us and them that have no observable (to us) matter.

Here's a thought experiment to illustrate what I am talking about. There are three people in a line, each 30.5 meters away from each other. Tom is 30.5 meters from Dick, who is 30.5 meters away from Harry. The space between Tom and Dick would not be expanding, according to this. Neither would the space between Dick and Harry. Would the 61m gap between Tom and Harry would be subject to expansion, even though there is no expansion between the two pairs?

Or would this only hold true if there was no way of establishing absolute distance between Tom and Harry, and we rely on quantum effects such as redshifting to determine relative distances and direction?

The implications of either are pretty damned interesting, and I'd love to see a followup that addresses this aspect of the hypothesis.
 
2014-01-02 03:36:12 PM
 
2014-01-02 03:36:57 PM
Every quantum discussion I read makes me go from thinking I'm an above average, smart guy, to just realizing how stupid I really am.  It's like an instant knock-down on the ladder of humility.  Most tough subjects I can at least get an idea or faint clue what they're talking about, but with this stuff it might as well be Dumbledore explaining how magic works.
 
2014-01-02 03:38:17 PM

BolloxReader: OK, so I have a bit of an issue with how they phrased things in this article.  Specifically, the 60m. What does this 60m limit refer to? Is it an absolute point of reference, ie the Earth will end up in 60m chunks due to expansion (if there is nothing that reduces it smaller first? Or is it that if there is another observable particle within 60m then expansion can't occur?


60m is the length-scale on which interactions resulting from the expansion of the universe necessarily force a state collapse.  It's not the  only interaction that can force a state collapse (and thus, by the slightly fuzzy logic of TFA, cause classical physics to dominate) it just gives sort of a hard limit of "anything bigger than this won't have superposition or tunneling effects associated with it".

The math probably works out something like deriving Heisenberg's uncertainty principle, if you remember doing that back in college physics, just with different founding forces.  Start with the wave formulation, throw guiding forces at it until something sticks.
 
2014-01-02 03:39:05 PM

BolloxReader: OK, so I have a bit of an issue with how they phrased things in this article.  Specifically, the 60m. What does this 60m limit refer to? Is it an absolute point of reference, ie the Earth will end up in 60m chunks due to expansion (if there is nothing that reduces it smaller first? Or is it that if there is another observable particle within 60m then expansion can't occur? In which case the Earth itself is not subject to inflation, though empty spaces around it would be, if there is no stuff we can measure there?

For example, galaxies appear to be redshifted away because there are gaps more than 60m between us and them that have no observable (to us) matter.

Here's a thought experiment to illustrate what I am talking about. There are three people in a line, each 30.5 meters away from each other. Tom is 30.5 meters from Dick, who is 30.5 meters away from Harry. The space between Tom and Dick would not be expanding, according to this. Neither would the space between Dick and Harry. Would the 61m gap between Tom and Harry would be subject to expansion, even though there is no expansion between the two pairs?

Or would this only hold true if there was no way of establishing absolute distance between Tom and Harry, and we rely on quantum effects such as redshifting to determine relative distances and direction?

The implications of either are pretty damned interesting, and I'd love to see a followup that addresses this aspect of the hypothesis.


In your thought experiment your Dick is being stretched and inflated.
 
2014-01-02 03:39:38 PM

BolloxReader: OK, so I have a bit of an issue with how they phrased things in this article.  Specifically, the 60m. What does this 60m limit refer to? Is it an absolute point of reference, ie the Earth will end up in 60m chunks due to expansion (if there is nothing that reduces it smaller first? Or is it that if there is another observable particle within 60m then expansion can't occur? In which case the Earth itself is not subject to inflation, though empty spaces around it would be, if there is no stuff we can measure there?

For example, galaxies appear to be redshifted away because there are gaps more than 60m between us and them that have no observable (to us) matter.

Here's a thought experiment to illustrate what I am talking about. There are three people in a line, each 30.5 meters away from each other. Tom is 30.5 meters from Dick, who is 30.5 meters away from Harry. The space between Tom and Dick would not be expanding, according to this. Neither would the space between Dick and Harry. Would the 61m gap between Tom and Harry would be subject to expansion, even though there is no expansion between the two pairs?

Or would this only hold true if there was no way of establishing absolute distance between Tom and Harry, and we rely on quantum effects such as redshifting to determine relative distances and direction?

The implications of either are pretty damned interesting, and I'd love to see a followup that addresses this aspect of the hypothesis.


Dude, you are so high right now
 
2014-01-02 03:44:41 PM

Barry Lyndon's Annuity Cheque: "Gravity is the universe observing itself into reality," said the physicist Deepak Chopra after ripping a hit on his bong.


FTFY.
 
2014-01-02 03:45:01 PM

Frozboz: Every quantum discussion I read makes me go from thinking I'm an above average, smart guy, to just realizing how stupid I really am.  It's like an instant knock-down on the ladder of humility.  Most tough subjects I can at least get an idea or faint clue what they're talking about, but with this stuff it might as well be Dumbledore explaining how magic works.


Funnily enough, reading any kind of literary criticism makes me feel exactly the same way. In fact, just participating in a book club discussion with other middle-class people can make me feel that way -- "We read the same book, and all I got out of it was a story".
 
2014-01-02 03:45:54 PM

BolloxReader: Here's a thought experiment to illustrate what I am talking about. There are three people in a line, each 30.5 meters away from each other. Tom is 30.5 meters from Dick, who is 30.5 meters away from Harry. The space between Tom and Dick would not be expanding, according to this. Neither would the space between Dick and Harry. Would the 61m gap between Tom and Harry would be subject to expansion, even though there is no expansion between the two pairs?


I think its more like this.
Tom, Dick and Harry are very hyper little kids that bounce around / vibrate. You put them on an stretching/expanding surface. At less than 60 m difference by looking at two kids you can't tell if the fabric has actually stretched and pulled them apart, of if they simply have moved apart on their own?
 
2014-01-02 03:46:33 PM

FitzShivering: As a guy on acid in college told me, "It's all just a spiral, man. Can't you see them? The whole universe is spirals, man."


Well, that's technically true. It looks like this:

www.leaningtowerofpisa.net
 
2014-01-02 03:48:50 PM

BolloxReader: There are three people in a line, each 30.5 meters away from each other. Tom is 30.5 meters from Dick, who is 30.5 meters away from Harry. The space between Tom and Dick would not be expanding, according to this. Neither would the space between Dick and Harry. Would the 61m gap between Tom and Harry would be subject to expansion, even though there is no expansion between the two pairs?


No, the space is expanding, we just couldn't tell experimentally except between Tom and Harry. As the Hubble Constant increases, this distance of uncertainty shrinks.
 
2014-01-02 03:49:28 PM
60 meters? That's gonna be a BIG computer.
 
2014-01-02 03:50:10 PM

czetie: Funnily enough, reading any kind of literary criticism makes me feel exactly the same way. In fact, just participating in a book club discussion with other middle-class people can make me feel that way -- "We read the same book, and all I got out of it was a story".


Eh, those are different problems.  People don't understand literary analysis usually because they don't have the broad knowledge base required... just read a lot and it'll come, you don't really have to train in a specific skill you don't already have, just expand what you've got.

People have trouble with QM usually because they're trying to start with the physics, never having learned the math that forms the basis of the language QM is written in.  Trying to learn QM without at least mastery of vector calculus and basic set theory is sort of like tackling your literary analysis issue without ever having learned to  read, period.
 
2014-01-02 03:50:37 PM

Frozboz: Every quantum discussion I read makes me go from thinking I'm an above average, smart guy, to just realizing how stupid I really am.  It's like an instant knock-down on the ladder of humility.  Most tough subjects I can at least get an idea or faint clue what they're talking about, but with this stuff it might as well be Dumbledore explaining how magic works.


Don't feel stupid. Arguing quantum theory is like trying to win at make-believe.
 
2014-01-02 03:50:59 PM
You really want to bake your noodle, read about how time only exists if you're entangled in the Universe.
 
2014-01-02 03:54:03 PM
FTA:  In other words, every galaxy in the cosmos is accelerating away from us.

So, intergalactic collisions are one less thing I have to worry about? Whew.
 
2014-01-02 03:56:02 PM
www.strangefunkidz.com
 
2014-01-02 03:57:43 PM

BolloxReader: Is it an absolute point of reference, ie the Earth will end up in 60m chunks due to expansion (if there is nothing that reduces it smaller first?


No, it's like you don't register the effect 60m away. it's not 60m sections.

It's like if you look at a forest far away you might only see a green field and can no longer see specific trees but the trees closer to you you can identify individually. Those other trees are not magically turned into a see of green because you see them that way.

It's the same thing. The quantum effects only have a certain radius that things effect each other.
 
2014-01-02 04:00:08 PM

HairBolus: BolloxReader: Here's a thought experiment

Your question seems related to "How can the universe be expanding faster than the speed of light when nothing can go faster than the speed of light".


Well, that is actually easy to answer. Lots of things travel faster than the speed of light... it's just that those things never go slower than the speed of light, they don't cross that barrier. I knew since middle school when I looked at the summary of results of the Fermi Accelerator and their implications for physics (for a project on antimatter for a science fair) that the whole "nothing goes faster than light" is a gross oversimplification of "If it starts out slower than the speed of light then it will never go the speed of light." If you consider the Big Bang as an instant effect (ie taking no time at all, literally happening between the ticks of an atomic clock) then there could be many things going faster than the speed of light that we are simply unable to measure in a meaningful way. I'm talking subatomic particles with no mass, here. And the fabric of the universe (if such an artificial mental construct can be legitimately reified, which is essentially what we do to model mass and gravity) would have been born at that speed.

And one thing to keep in mind is that we can only observe as far as light has traveled, and for all we know expansion has always maintained a general constant speed but we simply can't detect it because we can't see beyond a certain radius, and we are seeing localized eddies. Hell, it could even be "expansion" friction caused by rubbing up against some other universe, slowing the expansion of both over a localized area. Not that it would be meaningful for us in any way that I can see if that were the case. We have to live with the universe and rules we live in.

I don't have a problem with that notion at all. As long as quantum effects only exist on a level below the Planck length, certain things make sense. They are confined to oddball situations that may make for fun discussions but keep the universe that we experience nice and predictable like it always has been. That is a comfort. If we suddenly say that quantum effects are limited to 60m due to observable effects of expansion, I would really like to know what it is we are actually measuring with that distance. Those kinds of limits don't "just happen." They are hard boundaries because of how forces interact in fundamental ways. Unless it is tied in some causal way to gravity, it would seem to require a new sort of force or new type of interaction between existing forces to explain that break.

That there is a limit at which quantum and classical forces operate is pretty obvious and it would be cool to nail it down. I just want to see something more than a thought experiment because I can show you a thought experiment that proves that my half dozen unsold movie scripts make me a millionaire even after partnering with a lawyer and taxes. But my bank just doesn't agree with that assessment. I'd like to see more details, in other words, something more solid before I go around telling people that they've found the quantum limit.
 
2014-01-02 04:05:07 PM

theorellior: You really want to bake your noodle, read about how time only exists if you're entangled in the Universe.


So not only is gravity the universe observing itself into reality, I experience time because my quantum bits are buzzing at the frequency of the universe. I'm going to go lie down now.
 
2014-01-02 04:05:32 PM

ReverendJynxed: Frozboz: Every quantum discussion I read makes me go from thinking I'm an above average, smart guy, to just realizing how stupid I really am.  It's like an instant knock-down on the ladder of humility.  Most tough subjects I can at least get an idea or faint clue what they're talking about, but with this stuff it might as well be Dumbledore explaining how magic works.

Don't feel stupid. Arguing quantum theory is like trying to win at make-believe.


... No?

You realize certain portions of quantum mechanics (including uncertainty.. or, at least, either uncertainty OR non-locality) have been demonstrated via experiment, right? (For instance, the Bell Theorem)
 
2014-01-02 04:10:19 PM
ih2.redbubble.net

July 3rd, 3085. Everyday I hear and I see eternity, I am frozen in all of my knowledge of forever. But I belong only to one girl, nowhere can I see more clearly than into her heart. When Beth feels heartbreak, I'm stranded in the stitchy and void, helpless to comfort her, for I am just a horse. Sleep now, Bravest Warriors, and dream of doors and keys and Ralph Waldo Pickle Chips, today something unnatural has slipped into your universe, an auctive of death, a tentacle of time, it is the final gift and it is not for you, Beth does not know it now, but this gift is for her.
 
2014-01-02 04:10:20 PM

MindStalker: BolloxReader: Here's a thought experiment to illustrate what I am talking about. There are three people in a line, each 30.5 meters away from each other. Tom is 30.5 meters from Dick, who is 30.5 meters away from Harry. The space between Tom and Dick would not be expanding, according to this. Neither would the space between Dick and Harry. Would the 61m gap between Tom and Harry would be subject to expansion, even though there is no expansion between the two pairs?

I think its more like this.
Tom, Dick and Harry are very hyper little kids that bounce around / vibrate. You put them on an stretching/expanding surface. At less than 60 m difference by looking at two kids you can't tell if the fabric has actually stretched and pulled them apart, of if they simply have moved apart on their own?


Ah, so the space is still expanding it just that on a scale smaller than 60 meters you can't measure it? If that's right it makes much more sense than whatever the article said.
 
2014-01-02 04:11:45 PM
So the Universe is about 180 feet off, and we're going to need volunteers to move it a little that way.
 
2014-01-02 04:13:37 PM

Frozboz: Every quantum discussion I read makes me go from thinking I'm an above average, smart guy, to just realizing how stupid I really am.  It's like an instant knock-down on the ladder of humility.  Most tough subjects I can at least get an idea or faint clue what they're talking about, but with this stuff it might as well be Dumbledore explaining how magic works.


It's like all the scientists got together and were like 'Fark, I don't know how things work, but we can't let anyone else know that, so let's make some really crazy shiat up and see what happens!'
 
2014-01-02 04:14:44 PM
Were any physicists trying to measure cosmological expansion on scales of less than 60m to begin with?
 
2014-01-02 04:38:26 PM
Wait... Gravity is the universe observing itself into reality? Man, id love to read more on this. I haven't heard that analogy before.

/can't really keep up with theories of the universe.
 
2014-01-02 04:40:12 PM
I am the Excession.
 
2014-01-02 04:48:06 PM
i.imgur.com
 
2014-01-02 05:04:18 PM

Corvus: It's like if you look at a forest far away you might only see a green field and can no longer see specific trees but the trees closer to you you can identify individually. Those other trees are not magically turned into a see of green because you see them that way.


So this is less a problem with quantum theory than it is with our means of observation?

// which, I guess, covers ALL the problems in quantum theory?
// HALP
 
2014-01-02 05:12:46 PM
I always figured it was some wibbly wobbly thing to do with field flux through a number of dimensions. The more dimensions they act over the greater the flux over the radius from a point.
 
2014-01-02 05:13:08 PM
yeah but watch a theoretical physicist try to solve an emotional problem and you won't feel as inadequate.
 
2014-01-02 05:41:07 PM
The universe is a spherical region seven hundred and five meters in diameter.
 
2014-01-02 05:54:37 PM
The whole "expanding universe" thing is derived from the FRW equations, which are Einstein's equations when the universe contains nothing but perfectly homogenous gas/dust/radiation/stuff. This is what makes the entire monstrous system of nonlinearly coupled PDEs reduce to a simple scale factor a(t) from which we measure the expansion rate (da/dt) and the acceleration (d2a/dt2).

The universe isn't homogeneous except on literally cosmological billion-light-year scales anymore. The FRW equations do not apply on scales smaller than galactic clusters. Problem, article?

Color me skeptical... very skeptical. That this article was devoid of anything that required LaTeX doesn't help.
 
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