Register | Sign In


Understanding through Discussion


EvC Forum active members: 65 (9162 total)
2 online now:
Newest Member: popoi
Post Volume: Total: 915,819 Year: 3,076/9,624 Month: 921/1,588 Week: 104/223 Day: 2/13 Hour: 0/1


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   Why Parallel Universes?
Mike Holland
Member (Idle past 484 days)
Posts: 179
From: Sydney, NSW,Auistralia
Joined: 08-30-2002


Message 46 of 67 (140225)
09-06-2004 1:40 AM
Reply to: Message 33 by Primordial Egg
08-27-2004 8:22 PM


Re: quantum suicide
PE, this is in response to the reference you sent me.
I have at last managed to wade through ‘The Role of Decoherence in Quantum Theory’. Did you post this as a joke? It reads like an essay in Post-Modernism. I have never heard the term ’Decoherence’ before, but it sounds like things falling apart, with the inevitable result of ’Incoherence’. My spell-checker doesn’t like it either. I suggest you choose references from an Encyclopaedia of Science rather than an Encyclopaedia of Philosophy! I checked it all out in my 'Feynman Lectures', published in 1961, and it was all there expressed in simple english.
Anyway, the article does not say anything that I had not read decades ago, and I could not find any relevance to the multiple-universe interpretation of quantum-field collapse (decoherence?).
So, back to the subject of parallel universes splitting from each other.
Firstly, I can see two possible processes of ‘splitting’. Either the whole universe splits apart in one go, or the else split initiates in that volume where the collapsing quantum field had a non-zero amplitude, and then propagates over the rest of the universe at the speed of light. This latter process could be likened to spreading two sheets, one on top of the other, and then lifting the top one at its centre. The separation spreads outwards in a circle.
In the first case, our local space is being split continuously by ‘quantum collapses’ that occur all over the universe. If the universe is infinite, we have an infinity of splits at every instant.
In the second case, we have splits arriving here all the time, from events in distant space and time. For example, an electron being absorbed by a molecule somewhere in a distant galaxy a thousand million years ago! In this case the number of splits may not be quite infinite if the universe has a finite past - but what difference will it make?
So what is the point of talking about a quantum collapse event splitting the universe into two (or more) parallel universes when at the same time an infinity of splits take place due to other events?
That bullet goes through your head in an infinity of infinities of universes, and it doesn't go through in another infinity of infinities of universes. Which infinity is greater?
Mike.

This message is a reply to:
 Message 33 by Primordial Egg, posted 08-27-2004 8:22 PM Primordial Egg has replied

Replies to this message:
 Message 47 by Primordial Egg, posted 09-07-2004 7:55 PM Mike Holland has replied

  
Primordial Egg
Inactive Member


Message 47 of 67 (140789)
09-07-2004 7:55 PM
Reply to: Message 46 by Mike Holland
09-06-2004 1:40 AM


Re: quantum suicide
Hi Mike,
I have at last managed to wade through ‘The Role of Decoherence in Quantum Theory’. Did you post this as a joke? It reads like an essay in Post-Modernism. I have never heard the term ’Decoherence’ before, but it sounds like things falling apart, with the inevitable result of ’Incoherence’. My spell-checker doesn’t like it either. I suggest you choose references from an Encyclopaedia of Science rather than an Encyclopaedia of Philosophy! I checked it all out in my 'Feynman Lectures', published in 1961, and it was all there expressed in simple english.
Decoherence is now a proper proper physics term, honest. You can see references to it in all sorts of physics publications e.g:
Page not found | American Institute of Physics
http://www.physics.uiuc.edu/...hlights/entangled-photons.htm
http://physics.nist.gov/MajResProj/QuantumInfo/quantum.html
Home – Physics World
http://www.uni-protokolle.de/buecher/isbn/3540411976/
I wasn't making the word up! Does your spell checker like the word "inflaton", or "hadron" or "p-brane"?
You're right though, I saw you're initial question, thought to myself "decoherence", googled it, saw an article that covered it in some depth which I skimmed and was going to use in an answer to you and then ran out of time, so posted the link instead. With the benefit of hindsight, I would instead have posted the link I posted in a later message:
The Everett Interpretation
which is less clunky and more relevant. My apologies if you felt your time was wasted - I don't think the article I originally linked to was that bad though.
So I guess its incumbent upon me to attempt more explanation this time and less linking. I'm not an expert and all my info comes from reading non-technical books and articles, but I'll give it a go:
Firstly, I can see two possible processes of ‘splitting’. Either the whole universe splits apart in one go, or the else split initiates in that volume where the collapsing quantum field had a non-zero amplitude, and then propagates over the rest of the universe at the speed of light. This latter process could be likened to spreading two sheets, one on top of the other, and then lifting the top one at its centre. The separation spreads outwards in a circle.
I don't really understand what you mean by a parallel universe propagating at the speed of light. What's propagating through what?
My take on it is to imagine Schrodinger's cat, set up the experiment as normal and then throw out the cat and put yourself in the box. According to your assistant outside the box (who subscribes to the Copenhagen interpretation), you are in a state of quantum superposition, 50% alive and 50% dead. According to the many worlds interpretation you are either dead or alive. I'm pretty confident that either dead OR alive other would accord with what you experience, so of the two its only the MWI which allows for a sharply defined version of what we can describe as reality, in terms of agreement between different observers.
With MWI, a universe branches off everytime a new measurement is made - e.g on the two slit experiment the universe branches off once the photon hit the detector, with all physically allowable possibilities being realised. In fact the only rational explanation for single photons building up an interference pattern which is dependent upon the paths available to it must indicate that the photon is interfering with another photon somehow. The MWI provides all the necessary predictive power that QM has without any of that pseudoscientific mumbo jumbo about a conscious observer or the nature of reality being "mysterious".
In the first case, our local space is being split continuously by ‘quantum collapses’ that occur all over the universe. If the universe is infinite, we have an infinity of splits at every instant.
In the second case, we have splits arriving here all the time, from events in distant space and time. For example, an electron being absorbed by a molecule somewhere in a distant galaxy a thousand million years ago! In this case the number of splits may not be quite infinite if the universe has a finite past - but what difference will it make?
I'd agree with the first case and not sure about the second case. We can only observe the Universe we're in. This may sound tautological, but the chances are that we're in a Universe which is in no way out of the ordinary.
Its only recently that MWI vs Copenhagen has moved from a pithy and fruitless debate between philospophers and renegade physicists to growing speculation that it might actually be testable, of which quantum suicide is probably the most outlandish (and my favourite) example.
Well, actually there's an extension of this that say's imagine there was a freakishly bizarre quantum event which stopped you from dying at the very moment you would normally die in the majority of universes. In at least one universe these freakish events would continue to be experienced by you again and again and again....you'd never die. So, the argument goes, if the MWI is accurate, we are ALL effectively immortal. Personally, I can't see the flaw in the logic here although even Tegmark himself doesn't go this far. I'm not about to go jumping off any roofs to test it out just yet though.
That bullet goes through your head in an infinity of infinities of universes, and it doesn't go through in another infinity of infinities of universes. Which infinity is greater?
Well that's the nub you see - the whole point of the experiment. Let's simplify it a bit and say there's a 99% chance of you dying.
So in 99% of all universes you are no longer conscious of anything, your assistant is left to scoop your quivering brain matter off the floor.
In 1% of universes you are still conscious, albeit slightly soiled.
The key here is realising that what is it that YOU experience as you undergo the experiment will always be the 1% of cases - how could you possibly experience anything else?
Hope that was clearer. Sorry once more for the duff link.
PE
This message has been edited by Primordial Egg, 09-07-2004 07:00 PM

This message is a reply to:
 Message 46 by Mike Holland, posted 09-06-2004 1:40 AM Mike Holland has replied

Replies to this message:
 Message 48 by Mike Holland, posted 09-08-2004 2:56 AM Primordial Egg has replied

  
Mike Holland
Member (Idle past 484 days)
Posts: 179
From: Sydney, NSW,Auistralia
Joined: 08-30-2002


Message 48 of 67 (140888)
09-08-2004 2:56 AM
Reply to: Message 47 by Primordial Egg
09-07-2004 7:55 PM


Re: quantum suicide
Thanks PE. Therre was one sentence in the article that I really couldn't take seriously - 'Suppression of interference can be an extremely fast process, depending on the system and the environment considered'. You have to watch closely, or you might miss it!
But back to the speed of splitting. Do you imagine it as instantaneous? We perform the classical Schrodinger's cat experiment and open the box to find a dead cat (hope this example doesn't upset you). Then does Ygab on planet WW23W in the Andromeda galaxy immediately become two Ygabs in two separate universes? Even though the probability wave of the cat did not extend that far? You keep using the suicide example, with an action in our immediate present, but I am trying to see the process in relation to quantum events millions of light-years away.
Mike.

This message is a reply to:
 Message 47 by Primordial Egg, posted 09-07-2004 7:55 PM Primordial Egg has replied

Replies to this message:
 Message 50 by Primordial Egg, posted 09-08-2004 3:37 PM Mike Holland has not replied

  
portmaster1000
Inactive Member


Message 49 of 67 (141000)
09-08-2004 3:35 PM


The PC and reality overload
With the advent of billions of microprocessors performing millions of binary operations per second, would there be a parallel universe for an error in each of the binary operations? Let's say in our universe, a binary operation correctly returns a 1 in another universe does that operation return a 0 causing an error? If so, the Information Age has increased the rate of parallel universe creation by a great deal. Can we ever overload reality with too many parallel universes?
Not trying to be overly serious with this post... just curious
thanx
PM1K

Replies to this message:
 Message 51 by Primordial Egg, posted 09-08-2004 3:43 PM portmaster1000 has replied

  
Primordial Egg
Inactive Member


Message 50 of 67 (141002)
09-08-2004 3:37 PM
Reply to: Message 48 by Mike Holland
09-08-2004 2:56 AM


Re: quantum suicide
I hadn't really considered the speed at which the universes "peel" away - off the top of my head, I would imagine this to be instantaneous (rather like when a measurement is made on an entangled particle it has an instantaneous "effect" on its entangled partner), but not really sure why this is important.
If we think of Ygab performing a Schrodinger's cat experiment in her laboratory then I suppose that, yes, we split at the instant the experiment is performed. The probability wave of the cat spreads out across the whole universe, as far as I can recall.
PE

This message is a reply to:
 Message 48 by Mike Holland, posted 09-08-2004 2:56 AM Mike Holland has not replied

  
Primordial Egg
Inactive Member


Message 51 of 67 (141003)
09-08-2004 3:43 PM
Reply to: Message 49 by portmaster1000
09-08-2004 3:35 PM


Re: The PC and reality overload
ah but what about all those other universes where the development of microprocessors happened much earlier?
PE

This message is a reply to:
 Message 49 by portmaster1000, posted 09-08-2004 3:35 PM portmaster1000 has replied

Replies to this message:
 Message 52 by portmaster1000, posted 09-08-2004 4:48 PM Primordial Egg has not replied

  
portmaster1000
Inactive Member


Message 52 of 67 (141022)
09-08-2004 4:48 PM
Reply to: Message 51 by Primordial Egg
09-08-2004 3:43 PM


Re: The PC and reality overload
Primordial Egg writes:
ah but what about all those other universes where the development of microprocessors happened much earlier?
I'm all for blaming them when reality falls apart...
If we can have a universe where all coin tosses always come up heads can we have a universe where every operation of every microprocessor errors out all the time?
thanx
PM1K

This message is a reply to:
 Message 51 by Primordial Egg, posted 09-08-2004 3:43 PM Primordial Egg has not replied

  
nipok
Inactive Member


Message 53 of 67 (141529)
09-11-2004 10:05 AM


Unparalleled
It is the very like possibility that at each split point one of the two occurrences takes place and the other does not take place. It is much more likely that our reality is the only reality and there are no parallel universes that split off. It would seem to me that a paradigm that needs to include virtual particles and parallel universes must really have some significant bruises to require such absurd band-aids. It is time we begin to step backwards and peel off layers, not of parallel universes but layers off the current paradigm. Peel off the band-aids on top of band-aids on top of band-aids and lets start examining the underlying need for the first band-aid and see if there isn’t a better way to heal the paradigm. Once we can examine the plausibility of sub-point particles its funny how things like Feynman Renormalization, perturbation theory, parallel universes, vacuum fluctuations, and others all go out the window when we examine the option of sub-point particles and stop putting band-aids on top of band-aids. Build a better foundation and you will have a better house.

Replies to this message:
 Message 56 by Wounded King, posted 10-26-2004 5:12 AM nipok has not replied

  
The Dread Dormammu
Inactive Member


Message 54 of 67 (152992)
10-26-2004 4:04 AM


Identical hubble volumes
According to "Scientific American" There are at least 4 kinds of possible paralell universes. My personal favorite is the kind that can exsist right in our own space time. If our universe is realy infinite, (99.99 percent of universes with a microwave backround like ours should be infinte), AND There are limited number of possible confiugrations of matter inside any hubble volume (a hubble volume is the only volume of space we could ever see and interact with since objects outside of our hubble volume are accelarating away from us faster than the speed of light) then if you look out far enough in our OWN universe there is a hubble volume out there that is identical to our own! (though you could never actualy see or reach it)
Well I guess there doesnt HAVE to be one identical to our own but after a certian point they DO have to start repeating themselves.
Here's why using a handy metaphore:
In a Math class I took where we deturmened that there HAD to be a number of people living in new york city that had an identical number of hairs on their heads. If the maximum number of hairs on the human head is the maximum aria possible for a human scalp times the maximum possible number of hairs per square inch. Then any city with more residents then the maximum possible number of hairs nessesaraly has to have a number of people with an identical number of hairs on their heads. (It turns out that new york is such a city).
In the same way a space time with infinite hubble volumes will have some hubble volumes with identical configurations of matter.
In fact since it appears that on a realy large scale space is uniform (big foamy bubbles of superclusters). Then you don't have to go nearly as far to find identical hubble volumes (since there are no hubble volumes of completly empty space or ones with a maximum amount of matter)
Sadly we will never be able to reach these paralell identical hubble volumes. But I don't mind there is plenty to explore here in our own quant little hubble volume some 30 billion light years in diamiter.

Replies to this message:
 Message 55 by The Dread Dormammu, posted 10-26-2004 4:24 AM The Dread Dormammu has not replied
 Message 57 by The Dread Dormammu, posted 10-26-2004 8:12 AM The Dread Dormammu has not replied
 Message 58 by 1.61803, posted 10-26-2004 10:33 AM The Dread Dormammu has not replied

  
The Dread Dormammu
Inactive Member


Message 55 of 67 (152994)
10-26-2004 4:24 AM
Reply to: Message 54 by The Dread Dormammu
10-26-2004 4:04 AM


Regarding Time Travel
Brian Greene has a great explanition of time travel in his latest book. "The Fabric Of the Cosmos"
Basicly he says that there are 2 stances you can take on time travel that are not rife with parodox. The first stance is that when you travel back in time you merely travel to a paralell universe that is similar to you own. If you go back in time and attempt the cleche' killing of your own father, you can go ahead and kill him with no reprocussions because he is merely one of an infinie number of identical fathers. A parallel "you" will not be born in this universe but you (the one that killed your father) won't wink out of existance because you still have a father back in your own universe.
This is a very unristrictve kind of time travel in that you can do whatever you want and then see the reprcussions without worrying that you will wink out of existance. Remember you can travel forward in time just by accelarating so that if you wanted to see what a world would be like without you in it ala "it's a wonderful life" all you have to do is hop in your space ship and travel at a nice relativisitc speed.
The second interpretation is much more restrictive but still doesn't allow for paradox. It is my personal favorite becase it makes for good short stories.
In this interpretation of time travel When you travel back in time you DON'T go to a parralell universe. There is no need for multiple universes.
So what happens when you go back to kill daddy? You can't. Why not? Becase you exsist! and therefore couldn't have traveled back in time to prevent your own existance. The paradoxes come from the misconception that when you travel back in time, time "starts again" from where you arrive. But it doesn't! Everything has already happend.
If in the future you wind up going back in time, you are ALREADY there! When you travel back you can't "change things" to make a "second past." That past already exsits WITH your changes. Space time is then seen like a frozen river or a loaf of bread (Greene's term). If we could look at a time traveler outside of space time we would see his/her whole trajectory through space time as one solid unmoving shape.
I like this second intepretation best even if it does imply a kind of fatalistic deturminisum.

This message is a reply to:
 Message 54 by The Dread Dormammu, posted 10-26-2004 4:04 AM The Dread Dormammu has not replied

  
Wounded King
Member
Posts: 4149
From: Cincinnati, Ohio, USA
Joined: 04-09-2003


Message 56 of 67 (152995)
10-26-2004 5:12 AM
Reply to: Message 53 by nipok
09-11-2004 10:05 AM


Re: Unparalleled
So since you don't believe in virtual particles and vacuum fluctuations, how do you explain the Casimir effect?
TTFN,
WK
This message has been edited by Wounded King, 10-26-2004 04:13 AM

This message is a reply to:
 Message 53 by nipok, posted 09-11-2004 10:05 AM nipok has not replied

  
The Dread Dormammu
Inactive Member


Message 57 of 67 (153007)
10-26-2004 8:12 AM
Reply to: Message 54 by The Dread Dormammu
10-26-2004 4:04 AM


Re: Identical hubble volumes
I was wrong. Our hubble volume is actually Much much larger than that.

This message is a reply to:
 Message 54 by The Dread Dormammu, posted 10-26-2004 4:04 AM The Dread Dormammu has not replied

  
1.61803
Member (Idle past 1504 days)
Posts: 2928
From: Lone Star State USA
Joined: 02-19-2004


Message 58 of 67 (153033)
10-26-2004 10:33 AM
Reply to: Message 54 by The Dread Dormammu
10-26-2004 4:04 AM


Re: Identical hubble volumes
The dread doormamu writes:
But I don't mind there is plenty to explore here in our own quant little hubble volume some 30 billion light years in (sic)diamiter.
Not to mention the fact that our own planets oceans are largely unexplored.
This message has been edited by 1.61803, 10-26-2004 09:55 AM

"One is punished most for ones virtues" Fredrick Neitzche

This message is a reply to:
 Message 54 by The Dread Dormammu, posted 10-26-2004 4:04 AM The Dread Dormammu has not replied

  
SoulSlay
Member (Idle past 5611 days)
Posts: 44
From: billy's puddle, BC
Joined: 10-26-2004


Message 59 of 67 (153147)
10-26-2004 8:34 PM


The best way to kill your enemy (and get away with it)
To support the 'Dread Dormammu'
If you were to travel back in time (in your own universe) and kill your father, not much would happen, other than your mother being alone the rest of her life. If you are already in the year 1970(or whatever) to kill your father, you exist. After you kill him, he will fall down, and you will feel stupid. You will not discontinue existing. The atoms that make you up will not disperse back into the steak you ate when you were 4. If you then hop back into your time machine and come back to the present, you will still exist. The only difference is that you will not have been born in your new reality, but only in your old reality, and therefore nobody will know who you are. So I guess if you want to get away with murder, go back in time and kill your dad first...It's just the smartest thign to do...

Replies to this message:
 Message 60 by The Dread Dormammu, posted 10-26-2004 10:31 PM SoulSlay has not replied
 Message 61 by The Dread Dormammu, posted 10-26-2004 10:45 PM SoulSlay has not replied

  
The Dread Dormammu
Inactive Member


Message 60 of 67 (153187)
10-26-2004 10:31 PM
Reply to: Message 59 by SoulSlay
10-26-2004 8:34 PM


NO!
You said,
"If you were to travel back in time (in your own universe) and kill your father, not much would happen, other than your mother being alone the rest of her life. If you are already in the year 1970(or whatever) to kill your father, you exist."
No, according to the second unchanging theory YOU COULD NOT KILL YOUR FATHER if you traveld back in time to before you were born. Or if you could kill him you came into exsistance through some means that didn't nessesitate your father being alive before you were born.
In the second determainistic veiw there are NO multiple versions of history you either had a father that you went back in time and killed or you don't.
If the second determainstic veiw of spcaetime is correct then you only come into existance ONE way and history does NOT change even when you travel through time. If you remember your mother telling you that your father was killed by some mysterios stranger then maybe you did kill him. But One thing is certan, when you return to your own time you will find it is exsactly the same as when you left it*.
*Again according to the determanistic veiw of time travel.

This message is a reply to:
 Message 59 by SoulSlay, posted 10-26-2004 8:34 PM SoulSlay has not replied

  
Newer Topic | Older Topic
Jump to:


Copyright 2001-2023 by EvC Forum, All Rights Reserved

™ Version 4.2
Innovative software from Qwixotic © 2024