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Quantum Weirdness 108: Many Interacting Worlds

“Let your soul stand cool and composed before a million universes.”–Walt Whitman

“I believe we exist in a multiverse of universes.”–Michio Kaku

Note: at this point I am assuming anyone reading this has some handle on what Quantum Weirdness is, as well as the Copenhagen and Many Worlds interpretations thereof.  If you do not, go back and read the previous installments in this thread.

Much of this  Quantum Weirdness Primer thread , and it’s bigger sibling The Millennium Conjectures, has dealt with the two most popular interpretations of so-called quantum weirdness:  The Copenhagen interpretation and The Many Worlds interpretation.**   It should be noted that there are several other interpretations, but these two have garnered probably the most support among theoretical physicists.   I have joked that I personally am in an appropriate super-position on this question, simultaneously believing in both.  But like the wave function of a sub-atomic particle, my uncertainty has now collapsed into favoring a single interpretation that is not exactly either one.

This interpretation is called Many Interacting Worlds.   It professes a multiverse of interacting universes–which differs from the Everett’s Many Worlds interpretation in a very vital way.    Everett postulated that at each quantum “dice roll” the universe would split into alternate universes for each outcome.  These universes are forever separated and cannot communicate with or influence each other. Many Interacting Worlds states that there are a multitude of pre-existing nearby universes that interfere with each other on the quantum level, giving rise to the apparent weirdness.

From the standpoint of Schroedinger’s cat, we can look at it this way.   The Copenhagen Interpretation, views the cat as in a superposition of states, simultaneously alive and dead until an intelligent observer looks in the box.  The Many Worlds interpretation views the universe as splitting into two otherwise equal copies, one in which the cat is dead and one in which the cat is alive.  Each observer finds out which one he is in when he looks in the box.  The Many Interacting Worlds  interpretation effectively says that there are a multitude of nearly-identical universes that interfere with each other creating the quantum weirdness effects, ultimately determining whether the cat is alive or dead from your observation point.  Identical observers in parallel universes may see a different outcome.   The key difference is that the parallel universe in Many Interacting Worlds are not created at each quantum junction point–they already exist and interfere with each other giving rise to the phenomena of quantum weirdness.

Confused?  Well, as Feynman said, “nobody understands quantum mechanics.”   But here is an article describing the Many Interacting Worlds interpretation and its proponents claim that it may be testable.

 

**In his recent book, Our Mathematical Universe, Max Tegmark says “parallel universes are not a theory, but a prediction of certain theories.”  Specifically, there are two:  Eternal Inflation, which suggests what Tegmark defines as Level 1 and Level 2 multiverses,  and Quantum Mechanics, which gives rise to his Level 3 and Level 4 multiverses.  A detailed description of these multiverses is available on Tegmark’s web site.

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Conjecture #5: Quantum Solipsism (Part two)

“I’m not afraid of death.  I just don’t want to be there when it happens.”–Woody Allen

I conjecture:  In a Many Worlds quantum multiverse, each individual consciousness represents a distinctly different universe.

Part Two:  Quantum suicide and quantum immortality

Warning:  Professional stunt blogger.  Closed course.  Do not attempt at home.

To recap where we left off in our last episode,  the first part of Conjecture #5 suggested that, in a universe where the Many Worlds interpretation of quantum mechanics holds sway, each conscious entity represents its own distinct universe.   I called this Quantum Solipsism.  This differs somewhat from Conjecture #4, which suggested that in a universe governed, at least philosophically, by the Copenhagen interpretation,  our consciousness represents a composite of all the potential, but not real, universes.   This brings us to part two of Conjecture #5.

Quantum Immortality

Bold notions can sometimes breed extreme potential consequences.   When Hugh Everett posited the Many Worlds interpretation of quantum weirdness in 1954,  he didn’t just espouse it, he lived it.  He believed that in a world where every sub-atomic event splits off into a real alternate universe for every possible quantum outcome, that one’s own consciousness would always survive in some of them.  Quantum Immortality.  So he ate, drank and smoked himself to an early death–at least in the universe of everyone reading this post–by the age of 51.  His son expressed anger over his father’s failure to take care of himself.  His wife initially did not comply with his wishes to have his ashes disposed of in the trash, though eventually she did.   You think his views are extreme?  Or did he live on forever in a never ending series of alternate universes?  Consider this:  the quantum view of the second law of thermodynamics is purely a statistical one.  The reason all the air molecules in a room never seem to migrate to one corner is purely a matter of probability.  There are  staggering orders of magnitude more ways for them to be relatively evenly distributed.  But if every possible combination of such molecules actually exists as a real entity,  then somewhere  there is a universe where you suffocated last night because the air molecules in your bedroom did exactly that while you slept.   And somewhere, there is a universe where Hugh Everett’s ashes reassembled themselves and he woke up in a dumpster.

Quantum Suicide

This brings us to the ultimate in extreme ideas.  Quantum Suicide.  Originally conceived by Hans Morovec  in 1987 and further developed by Max Tegmark, it is a thought experiment designed to prove once and for all if the Many Worlds interpretation of Quantum Mechanics is correct.    If you recall from my Quantum Weirdness 101-107 series,  the Copenhagen interpretation sees the cat as neither dead, nor alive, until an intelligent observer intervenes.  The Many Worlds interpretation, sees the the creation of two separate universes, one each for a dead cat and a live cat, and the observer only finds out which one he is in when he looks in the box.   The quantum suicide gun re-creates the Schrodinger’s Cat experiment from the point of view of the cat.  Theoretically, it could prove the many world’s interpretation, though there are a couple of hitches.  If Many Worlds holds true,  the subject would be the only one it would be proved to;  if it does not hold true, the subject would be dead, period.  See the video below for a complete explanation, and as stated in the warning above, do not attempt this at home.  I sure won’t.  On the other hand, I can think of a few people I wish would try it…

(Video Credit: AliceandBobTV)

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Time Out: Time Out Time Out Time Out Time Out Time Out Time Out Time Out…..

“Science is more amazing than science fiction.”–Brian Greene

Bubble, Bubble toil and multi-trouble...

Bubble, Bubble toil and multi-trouble…

As much fun as it is to speculate about alternate or parallel universes,  many have said to me,  it is silly to even try if there is no way to prove or disprove their existence.  You might as well speculate on how many angels can pirouette on the head of a pin.  Because there is no empirical means of proof.  Or is there?  In the last couple of weeks I have seen not one, but two suggestions that physical evidence may have indeed been found for the existence of alternate planes of reality.  And they point to two distinctly different types of alternate universes.  The ideas behind them are not new…but growing evidence is beginning to support the possibility–if not the absolute proof–that they are real.   The first is in the microwave background radiation–the infant footprint of the early universe if you will.  Brilliant and controversial physicist Roger Penrose now asserts that circles in the background radiation–anomalies that should not exist by any known cause within our current universe–are proof of a cyclical universe with repeated big bangs. One might call this a serial, rather than parallel, multiverse. It turns out, though, that this also is possible evidence for the “bubble” multiverse theory discussed by Brian Greene in the video linked below.  His most recent book, The Hidden Reality, is a discussion of the current state, in theory and possible practice, of the various multiverse concepts.

A second possible proof,  of a different type of multiverse (and let’s not forget that Max Tegmark defines four different levels of multiverse) has also been in the news again recently.  It suggest an alternate universe described by M-Theory, where another universe may sit in a higher dimensional space infinitesimally close to us, yet unable to interact in any way.  Except one, that is.  Gravity.  And some astrophysicists interpret otherwise unexplained gravitational influences in the cosmos as possible proof of this theory.

Where do I stand on this?  As stated in my post on possibilianism, I prefer possibilities to certainties; it makes existence far more interesting.  But I must admit:  I am secretly wishing to be able to travel to a parallel universe where that library book I forgot to return in 1989 isn’t 24 years overdue.

http://science.discovery.com/tv-shows/brink/videos/brink-multiple-universes.htm

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Conjecture #2: Inevitability (Part 1)

I Conjecture:  In an infinite multiverse we must exist.

Part One: Inevitable existance

“Everything not forbidden is compulsory.”–

T.H.White, The Once and Future King

The quote above is from fiction;  in reality is anything but.  It has been echoed by Nobel physics laureate Murray Gell-Mann and effectively, if not literally, by many other scientists.  The message of the random, probabilistic nature of the sub-atomic quantum world is clear:  given enough matter, energy and 4-dimensional space time, anything that is physically possible will eventually happen.  If you roll the dice enough times, you will get every possible result.  If you add an infinite multiverse–and remember, the many worlds interpretation  of the multiverse is only one of four types of postulated multiverse–then it is conceivable that every possible set of physical laws exists somewhere.   To some, this may appear to be just a restatement of the anthropic principle, and they may be right.  Others may say that just the mere fact that we do exist makes this a moot point, and perhaps that could be construed as what I am saying.  Admittedly we are getting down to semantics and philosophy as much as science.

But to reiterate this conjecture flat out,  we exist because it is impossible for us not to.  The justification for this statement is hardly original, and the statement itself has at least been alluded to by philosophers since the ancient Greeks.  Friedrich Nietzsche expounded it as The Eternal Recurrence. It is the notion that, in a Universe that is infinite in either space or time, everything physically possible must recur ad infinitum.   If that is the case, then it follows that it is inevitable that we would exist in the first place and inevitable that we will exist again and again in our current form as well as in every every possible variation.   MIT cosmologist Max Tegmark,  who as stated in a previous post defined the four levels of “other universes” in the multiverse, has taken this concept to an almost bizarre extreme.  He has specifically calculated how far you would have to travel to find another earth with an exact copy of yourself–if and only if our local universe extends infinitely beyond the 13.7 billion light year horizon that we are able to observe.    The number makes the Douglas Adams description of the universe as “mind-bogglingly big” appear to be sub-atomically small.  It is, in light years, a 1 followed by something like a million billion billion zeroes.  I don’t even know how to post that in scientific notation on WordPress. So if our existence is inevitably going to repeat itself in an infinite universe or multiverse, does it not follow that our existence is inevitable in the first place?  No, it does not.  This does not answer the question as to why there is something in the first place, rather than nothing. In part two of this conjecture I will address this question in both scientific and philosophical terms.  And the ultimate answer regarding the impossibility of non-existence will come from the same source as my justification for the conjecture of infinity.

All text in this post ©2012 Mark Sackler

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Conjecture #1: Infinity (Part Two)

I conjecture:  The concept of infinity could not exist in a finite universe.

Part Two:  The Possibility of Infinite Space

“The universe is a big place, perhaps the biggest.”– Kurt Vonnegut

Douglas Adams called the universe “mind-bogglingly big.”  But “mind-bogglingly big” pales next to infinitely big.  And while the question of space being infinite may be somewhat easier to get around than time, it is certainly no bargain.

The first problem is that Vonnegut is dead-on right.  Our universe is only possibly the biggest place.  It used to be that “universe” meant everything.  But then the concept of “multi-verse,” with countless alternate or parallel universes, began to creep into astrophysics and cosmology.  To make matters worse, there is not just one potential level of parallel universe proposed, but four.*  So far.  Physicist and author Paul Davies argues that the concepts, while fascinating to contemplate, amount to philosophy–or even religious faith–if you can’t test them.   David Deutsch, among others, disagrees and deduces that the many worlds interpretation of quantum mechanics is the only one that makes sense, in terms of scientific explanation.  I’ll have more background on the various arguments surrounding interpretations of quantum mechanics–particularly The Copenhagen Interpretation vs. all others–in future posts.

Getting back to the question of infinity of our universe and/or the multiverse, there is indeed some scientific investigation aimed at determining the potential infinity of our own visible universe.  It involves the topology of its three-dimensional space and whether it is flat or curved.   I can’t go into details, as it involves rather advanced calculations from observations of the Cosmic Background Radiation–the earliest remnants of the Big Bang we are able to detect with current technology.  But the weight of the existing evidence seems to be pointing towards a flat topology that could be infinite.  Add that to the possibility of countless alternate universes of various kinds,   and I will assume for our purposes that space is at least potentially infinite.  [For a discussion of actual vs. potential infinity, see the Wikipedia article].   In the final installment on this conjecture, I will address one dimension of existence that I feel without doubt is potentially infinite: human imagination.    For an extended, if somewhat dramatic discussion of the possibility of an infinite universe, watch the video linked at the bottom of this article.

7-year universe image of background microwave radiation from NASA’s WMAP probe. (2010)

*As classified by MIT cosmologist, Max Tegmark

Text of this post ©2012 Mark Sackler.

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