post

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.

post

Quantum Weirdness 107: Bell’s Inequality

Note:  I said in Quantum Weirdness 106 that I was done with this series for now.  There are two possibilities here.  Either my definition of “for now” is a very short time, or I have branched off into an alternate universe where the term “done for now” has no meaning.**  Then again, I could have branched off into an alternative universe where, instead of writing this post, I would be lying on a Mediterranean beach next to a super-model in a string bikini.   I wish.

**Okay, I might just have have lied.

“God does not play dice.”–Albert Einstein

“Quit telling god what to do.”–Niels Bohr

It’s complicated.  And this just about reaches the limit of my own understanding.

The whole point of Einstein’s comment is that he could not accept the random nature of the quantum world.  He could not accept that quanta of matter and energy, and all their itinerant properties, only exist as probabilities until we observe  them.  He felt that there must be hidden variables that gave them these properties whether anyone was watching or not.  “I’d like to think the moon is there whether I am looking or not,” he said.

He was wrong.  Well, I don’t know about the moon, as that invokes the infamous Schrödinger’s Cat problem and it’s obfuscation of the Copenhagen Interpretation.  But for those tiny little quantum bits of stuff, it seems as if he blew it.

It all boils down to two papers.  The first was a 1935 paper by Einstein, along with colleagues Nathan Rosen and Boris Podalsky that proposed a thought experiment to demonstrate that there are only two possible explanations for certain properties of quantum mechanics: either there are hidden variables governing the quantum world, or else, as Einstein called it “spooky action at a distance.”  This has become known as the EPR paradox.

The second was a 1964 paper by John S. Bell, proposing an equation and related experiment that could be used to determine which of the alternatives is correct.  This became known as Bell’s inequality.

The technology did not yet exist, though, to make the measurements required to determine the solution to Bell’s equation. That did not occur until Alain Aspect, et al, performed an experiment in 1981 that proved, finally, that Einstein was wrong: no hidden variables exist; it’s spooky action at a distance.  At least, that is,  until further notice.

A  fairly facile explanation of the concepts and history is available here (including a brief touching on their relationship to Schrödinger’s Cat) and some subsequent contrary opinions here.  Or for those who can’t (or prefer not to) read, see the video that follows.  Confused?  One of the greatest scientific minds of the 20th century, Richard Feynman, said that nobody understand quantum mechanics.  Boy, does that give me free rein to get crazy with conjecture #5: Quantum Solipsism.   There may actually be a universe where I finally write and post it.

Whew.

post

Quantum Weirdness 106: Are dreams real?

 “Reality is wrong.  Dreams are for real.”–Tupac Shakur

It has been advocated–I can’t recall by whom–that our sleep dreams may actually be real events in an alternate universe.   I doubt it;  that’s too far over the top for my taste.  But the following unusual dream–one I’ve actually had–will serve for now as my final installment of the Quantum Weirdness Primer.   It’s a fitting intro to my next two conjectures, both of which deal with the possible nature of consciousness in relationship to quantum physics.  The dream was short and unexciting, but opened up a Pandora’s box of questions.

The Infinite Office Building

The Flatiron building as it appeared around the time of my father's birth in 1919.  It wasn't actually in the dream, but it's just too cool not to include.

The Flatiron building as it appeared around the time of my father’s birth in 1919. It wasn’t actually in the dream, but it’s just too cool not to include.

I am working in an art-deco era office building in the Flatiron District of Manhattan.  It is a beautiful, clear spring day and the New York skyline fills my panoramic view.  I get up to go to the water cooler when a realization hits me.  This is an infinite office building with an infinite number of floors.  Every floor represents an alternate universe–an infinity of them.   Every possible universe that I could, or possibly do exist in, is here.   I ponder the implications and head toward a back staircase to explore.  Which way should I go? Up or down?  Where will it bring me?  But a chilling thought hits me just as lift my hand to open the exit door leading to the stairs.  What if I can’t find my way back?  Sure, this specific universe that I currently exist in must reside somewhere within an infinity of universes.   But by definition, if I explore starting from this one, there will always be a finite number behind me and an infinite number ahead of me.  I would likely never find my way back within my lifetime, or perhaps even an infinite number of lifetimes.  I lower my hand, go back to my office,  and wake up.

The dream is reminiscent of David Hilbert’s concept of the Infinity Hotel, an explanation of which is in the entertaining short video below.  Strangely enough, I first heard of this idea two weeks after having the Infinite Office Building dream, when I read about it in detail in David Deutsch‘s The Beginning of Infinity.  In any case, the conclusion I reached from my hesitance to explore, was a realization that maybe it really doesn’t matter how many potential or actual universes there are if we are only conscious in one.  Or one at a time.  Or does it?  I’ll discuss these enigmas in my next two Millennium Conjectures, after a finite number of intervening posts.   [Video credit: The Open University]

post

Quantum Weirdness 105, Review: How to teach Quantum Physics to Your Dog

        “I have a very good nose. I can sniff into extra dimensions. They’re full of evil squirrels. With goatees.”–

Chad Orzel’s dog, in How to Teach Quantum Physics to Your Dog.

Chad Orzel is my kind of guy.  If it wasn’t for the fact that How to Teach Quantum Physics to Your Dog was copyrighted in 2010, I would have sworn he had read my Law of Canine Chaos before writing the following.

Sound waves are pressure in the air.  When a dog barks, she forces air out through her mouth and sets up a vibrations that travel through the air in all directions.  When it reaches another dog, that sound wave cause vibrations in the second dog’s eardrums, which are turned into signals in the brain that are processed as sound, causing the second dog to bark,  producing more waves, until nearby humans get annoyed.  [emphasis mine]

Amen, brother.

But the point is, he explains and summarizes beautifully–and expands upon lucidly–all the points in my first four Quantum Weirdness posts.  He does so in a manner clear enough that, if you can’t understand it, at least your dog will.  Maybe the pooch can then explain it to you. Either way,  I recommend it highly.  Unfortunately, though,it seems to be out of print in the US.   It is available, mostly from the UK, from various resellers on ebay and barnesandnoble.com.  Orzel has also written How to Teach Relativity to Your Dog and How to Teach Physics to Your Dog.  Before you know it, those clever mutts will be running the LHC at CERN.  I doubt they will be looking for the Higgs Boson, though.

Copyright 1984, Chronicle Features

post

Quantum Weirdness 104: Heisenberg’s Uncertainty

“Doubt is unpleasant, but certainty is ridiculous.”–Voltaire

Heisenberg may be dead, but his uncertainty principal is alive and kicking.
(Image credit unknown)

It was the end of the Newtonian worldview.   Early in the 20th century relativity and quantum mechanics created a new scientific outlook on reality–counter-intuitive and downright….well…weird.  The final nail in the coffin of so-called Newtonian determinism was put forth by one Werner Heisenberg in 1927: the uncertainty principle.   Simply stated, you can’t exactly know both the momentum and location of a quantum object.  The more precisely you know one, the less precisely you know the other.   And while recent news headlines suggest to some that Heisenberg has been overturned, this is absolutely NOT the case.   It was thought that the very act of measuring a quantum particle added to the uncertainty, but that was never really part of Heisenberg’s equation–which in fact can also apply to macroscopic phenomena like sound and water waves.  So while a team from the University of Toronto was able to devise a means to measure a quanta (such as an electron or photon) with minimal increase in uncertainty, even they admitted “the quantum world is still full of uncertainty, but at least our attempts to look at it don’t have to add as much uncertainty as we used to think!”

Heisenberg’s principle plays a critical role in something that is rather significant in the foundations of modern philosophy, and as I see it, civilization itself.  That would be how we view the future.  This will be explained in the next conjecture.

Here is a simple video demonstration of the concept by Walter Lewin of MIT–a single-slit experiment.

If you’re brave enough to tackle the math, here is a link to another video from Mind Bites that explains it in terms so simple even I can understand it.  Er…maybe.

post

Quantum Weirdness 103: How Many Worlds?

“There is no question that there is an unseen world. The problem is, how far is it from midtown and how late is it open?” –Woody Allen

For the quantum physics-uninitiated, get ready for the weirdest of the weird: the many worlds interpretation of quantum mechanics.

In Quantum Weirdness 101, we talked about the wave-particle duality of sub-atomic quanta, and how they appear to be in a superposition of every possible trajectory and location until an observer measures them.

In Quantum Weirdness 102, we discussed The Copenhagen Interpretation, which basically states that reality is just fuzzy on that level.  They are only potential trajectories–probabilities–interfering with each other, and this doesn’t have a measurable effect on our everyday macro world.   But we also visited Schrödinger’s infamous cat–the mind experiment that poked a colossal hole in  Copenhagen.

Image Credit: University of Oregon, 21st Century Science

The Copenhagen interpretation remained the most popular explanation for decades, in spite of Schrödinger.   But in 1957 cosmologist Hugh Everett made an astonishing proposal.  He suggested that the particles themselves–not merely their probabilities–interfere with one-another.  In this interpretation, they actually take every possible trajectory, each in an alternate universe.  Effectively every physically possible history exists in a huge–possibly infinite–number of alternate universes. So when we look in the box containing that possibly dead or alive cat it is actually in two universes: alive in one, dead in the other.   We just see it in the one we are in.   Taken to the extreme, every one of us would exist in a countless number of alternate universes.   Some would be imperceptibly different from ours, in others we might not even recognize ourselves or the the world around us.  And while Everett was mostly ignored or derided in his day, his many worlds interpretation has become a leading explanation of quantum weirdness, rivaling even Copenhagen.

So where do I stand?  Agnostic.  It is a rather optimistic world view.  I hope it’s true; I’m afraid it isn’t.  But many of the world’s top physicists now lean towards many worlds, and David Deutsch, among others, makes some very convincing arguments using deductive reasoning if not direct evidence.  I will leave it at this: it is a strong possibility that greatly influences my millennium conjectures. For more detailed background, check out the Wikipedia articles on The Many Worlds interpretation,  as well as general overview of quantum mechanics interpretations.   Or if you prefer, here is an entertaining video, shamelessly lifted from YouTube.

post

Quantum Weirdness 102: Equal Time for the Cat

“I don’t like it, and I’m sorry I ever had anything to do with it.”
Erwin Schrödinger  (referring to Quantum Mechanics).

What better follow up to The Equation of Canine Chaos, then the infamous tale of Schrodinger’s Cat?

In Quantum Weirdness 101, we saw that the double-slit experiment revealed the wave-particle duality of sub-atomic quanta, and the fact that these troublesome little bits behave as if they are everywhere they could possibly be at once until an observer looks for them.  While the experimental proof that this happens is rock-solid, the explanation for what causes it is anything but.  For decades after its original discovery in the 1920’s, the predominant interpretation—essentially, in fact, the only one—was the so-called Copenhagen Interpretation.  It essentially states that the universe is just fuzzy on the sub-atomic level, it doesn’t affect our everyday macro-world, and we mortals should not worry about it otherwise.  Critics have said it is really no interpretation, and some facetiously call it the “shut-up-and-calculate” interpretation.   In 1935, Erwin Schrodinger posed perhaps the most famous mind experiment in all of physics to show that theoretically the Copenhagen Interpretation makes no sense.  More recently, physicists have been able to succeed in creating this quantum superposition with larger and larger bits of matter, which tends to shoot empirical holes in Copenhagen.

Anyway, this witty video does a good job of explaining the concept behind Schrodinger’s Cat.  And I’m pretty sure that no cats were harmed in its making—much to the chagrin of my dogs.

In the next installment: the many worlds interpretation of quantum weirdness.

video

Quantum Weirdness 101:  The Double-Slit Experiment

“Anyone who is not shocked by quantum theory has not understood it.”–

Neils Bohr

With apologies to Douglas Adams–don’t panic!  Although an understanding of a few basic concepts of quantum mechanics will be helpful in following some of the Millennium Conjectures, it’s actually not that hard to grasp.  No math is needed.  The following video gives a clear and entertaining description of the wave-particle duality of the sub-atomic world.   If you weren’t already familiar with the concept, this should give you what you need to “get it.”   What it won’t allow you to do is come to grips with it, or even believe it.  But you’d better believe it.  Quantum theory is one of the most rock solid, experimentally verified fields in all of science.   And whether you believe it or not, don’t even think of explaining it.  The world’s most brilliant physicists have been debating the implications for decades and are nowhere near a consensus.   If you’d like a little more after the video, including a description of some of the leading explanations, here is a text primer.

%d bloggers like this: