Monday 8 March 2010

A Brief History Of Quantum Physics

Although at first this post may seem to have little to do with Lost, when you begin to consider the "alt" timeline playing out this season you will realise it has much relevance.

Quantum Physics
What is it?

Quantum - The smallest amount of a physical quantity that can exist independently.
Physics - The science that deals with matter, energy, motion, and force.

Essentially, quantum physics is the smallest parts of everything, so small in fact that it is impossible to measure these tiny parts. Instead, we must rely on mathematical theories, supposition, guesswork - like a typical episode of Lost, then.

Quantum physics, it is said, differs so far from "classical" physics as to completely defy "classical" laws of physics. It is this scientific rebellion that allows for the creation of theories such as alternative universes, time travel and deep space exploration - again, pretty much a typical episode of Lost.

So, how do we begin to explain that which cannot be seen, measured, understood or explained? Well, the simplest answer would be - we don't! I stop typing, you stop reading and we all go on with our lives.

But, there's no fun in that, is there?


The 1920s - Niels Bohr
"The Copenhagen Interpretation"

"Anyone who is not shocked by quantum theory has not understood it" - Niels Bohr.

Niels Bohr is widely regarded as the forefather of quantum theory. Although quantum mechanics, and thus quantum physics, had already been discussed and debated for many moons pre-Bohr, it was he who first attempted to explain this mysterious world in terms of classical physics.

Bohr suggested that, when observed, the quantum world becomes fixed and that we can use these measurements to describe a future state of whatever was observed. However, pre-observation, the quantum world exists in a rather random, chaotic existence.

This line of thought takes a lot to wrap your head around, so let's fast-forward a decade and view an experiment that you may be familiar with.


The 1930s - Erwin Schrodinger
"Schrodinger's Cat"

In 1935, seeing that quantum physics was essentially saying that every possibility of every state of every tiny part of everything always exists all the time until someone, somewhere, observes something, at which point reality collapses into one single, identifiable state - realising that this was a bit of a bizarre, some would say ridiculous, way to think about things, Schrodinger made an almost throwaway remark that many have taken to heart as a serious explanation of quantum physics theory.

Schrodinger's Cat - an experiment that involves locking a cat in a room with a machine, free of any kind of tampering, that after one hour will either kill the cat or not. Now, without observation, the room can be said to compose equally of parts dead cat and parts alive cat. Once the room has been observed, it becomes obvious there is either a dead or an alive cat, but until that time the room has both.

This paradoxical experiment was created in response to a theory called quantum entanglement, which derides quantum physics. Entanglement states that, taking quantum physics into account, an object can no longer be adequately described without mentioning all possible versions of that object, whether they exist or not. This fact turned many scientists away from the process of quantum physics, including Albert Einstein, who compared himself as a "gambler" more than a scientist if he had to take quantum physics into account.

"I find the idea quite intolerable that an electron exposed to radiation should choose of its own free will, not only its moment to jump off, but also its direction" - Albert Einstein.




The 1950s - Hugh Everett
"The Many-Worlds Interpretation"

Although Hugh Everett never coined the phrase "Many-Worlds" (that credit came later from Bryce Seligman DeWitt), he nevertheless provided the foundation for the "MWI". This explanation of quantum physics explains that, rather than being specific to a single observer, every version of everything must play out somewhere, and that no one person can conceive of these infinite possibilities.

Now, rather obviously, all these infinite versions of events cannot exist in one place, on one plane of existence. So it is that we get many worlds, many planes in which these events can take place. This is, apparently, backed up by the mathematics of quantum physics theory, but many leading quantum physicists, including Niels Bohr, essentially laughed in the face of the "Many-Worlds Interpretation", setting quantum theory back several decades.


The 1970s - Bryce Seligman DeWitt
Many-Worlds revisited

In a case of being in the right place at the right time, Bryce Seligman DeWitt resurrected Everett's theories by proposing that these "Multi" worlds were in fact parallel universes, existing in a dimension that is both spatially related to ours yet still isolated from ours, creating links, but extremely weak ones, between our universe and others.

This came at a time when scientists were beginning to accept that there may be far more dimensions in existence than those we had previously conceived of (as many as 11, as the 1990s may have shown us). The more dimensions that can exist, the more chance there is of understanding quantum physics and thus creating a singular theory of everything.


The 1980s - Various
"Quantum Decoherence"


Building upon Bohr's "Copenhagen Interpretation", the 1980s produced the theory of quantum decoherence, which aimed to show that it was not observation that caused quantum particles to fall into a particular state, but rather interaction with classical particles that caused the quantum particles to select an irreversible state, given the impression that observation creates reality.

Although these investigations have yet to yield conclusive evidence to prove, or disprove, the many theories of quantum physics, it does go some way to explaining why certain quantum states appear to conform to both (or either) of the Copenhagen or Many-Worlds interpretations.


The 1990s - Various
Splitting The Theories


In 1995, Edward Witten, a man being touted by some as "Einstein's successor", proposed a new 'super' string theory, the "M-Theory". This theory essentially shows that if we can conceive of a plane of existence that encompasses 11 dimensions, then we can finally begin to explain everything in relation to everything, in something called the multiverse.

I think it best if I leave string theory alone at the moment, but suffice to say Witten's proposals both encompass parallel universes, yet at the same time re-imagine how we think of parallel universes at the moment. If successful, the "M-Theory" (or "membrane") may be able to finally show the absolute truth of the matter.

Fast forward slightly to 1998, Max Tegmark put his own spin on the Schrodinger's Cat experiment by placing a human observer in the role of the Cat. This observer, now aware of the experiment, is said to be taking part in "Quantum Suicide" and furthermore "Quantum Immortality". The experiment differs slightly in that Schrodinger's Cat had one hour in which to either be alive or dead. In Tegmark's experiment, the observer/subject runs through a similar 50/50 chance of dying every 10 seconds. Each time this 10 second loop (see: Lost) elapses, the subject either dies or lives - either way, the experiment continues on regardless.

Every 10 seconds, it can be said a parallel universe exists. The subject is aware that, if he has survived, although he has an exact 50% chance of surviving again, in pure mathematical terms his chances of survival is in fact reduced (see: the film 21 for a good layman's term explanation of odds and statistics). After a certain length of time, the surviving subject(s) can come to perceive theirselves as immortal, while their deceased counterparts are, in some dimension, merely dead.

These experiments I cannot explain in simpler terms, and in fact many greater minds than I have resigned this thought process to the category of "we have to wait for the theory of everything to explain just what in the heck this all means". So let's move on.


The 2000s - Various
Piecing It All Together


In 2001, Neil Turok and Paul Steinhardt composed a new proposal to challenge what is already a challenging concept - the "Big Bang Theory". While the Big Bang theory is generally considered to be an explosion which began the rapid expansion and evolution of our universe, Turok and Steinhardt instead proposed that this explosion was the result of two parallel universes colliding, creating what they term the "Ekpyrotic Universe" (Greek for disastrous fire - read into that what you will).

This is but one recent example of how quantum physics, and the parallel worlds it has conceived of, is being applied to the practicalities of our universe.

"All structures that exist mathematically exist also physically" - Max Tegmark.

Back now to Max Tegmark, that great thinker who conceived of "Quantum Suicide" and "Quantum Immortality". A quick sidenote - while many take "Quantum Immortality" to mean that conscious beings must, in some form, live forever, Tegmark himself criticises this thought process.

Tegmark has began classifying parallel universes, and parallel universe theories, into four main categories - category I deals with universes beyond the sight of our own, but which have similar properties. Category II also lie beyond our sight but may have different properties. Category III are contained within the "Many-Worlds Interpretation", and Category IV universes may not even conform to the same laws of physics as our own - to put it blunt, category IV is inconceivable to us.

Also emerging in the 2000s is "Quantum Computing", where the principals of quantum physics and quantum mechanics are applied to computing - bits becoming qubits (quantum bits), etc. This should, hopefully, provide faster, better, more efficient, and generally astounding ways to handle data, mathematics and general geekery. It is worth mentioning, but has little to do with the parallel universes we as Losties are interested in.

What does concern us is deep space travel, and in specific black holes. In pop-culture terms, a black hole is a place in space where the laws of physics break down and anything possible can happen. Some scientists, such as mathematician Louis Crane, have been thinking about deep space travel and alternative fuels. One such fuel could be to harness the power of black holes at some point in the future.

This has led to ethical discussion on the balances of reward/danger of created a man-made black hole, owing to its unknown qualities. Lee Smolin has theorised that when a black hole is created, so too is another universe, accessible through the black hole. He goes on to suggest that some universes are more susceptible to creating black holes than others, and that our own universe could in fact be no more than an infant universe created not from a Big Bang (either isolated explosion or the result of two universes colliding), but in fact from a black hole created in some other universe.

This, he describes, is Charles Darwin's "Natural Selection" on the grandest scale - a universe contains intelligent life that desires to explore deep space for more intelligent life and in doing so creates black holes which in turn create intelligent life, and so on. Universes that harbour intelligent life have more of a chance of creating new universes - those that do not become evolutionary dead-ends. So we could, in essence, be playing "god" if we begin creating black holes.


Those People
In Brief


Max Planck - Began the quantum theory ball rolling by trying to explain how light can exist as both a wave and a particle; won a Nobel prize in 1918.
Niels Bohr - Began to explain quantum theory with the idea that observation creates reality; used this to explain the structure of the hydrogen atom (and thus all future understanding of all atoms); won a Nobel prize in 1922; worked as a consultant to the Manhattan Project (read: atomic bomb (read: Jughead)).
Erwin Schrodinger - Created the 'Schrodinger's Cat' experiment to show the fallacies of quantum physics; inadvertently created the de facto touchstone for all discussion on quantum physics; won a Nobel prize in 1933.
John Wheeler - Colleague of Niels Bohr and supervisor of Hugh Everett; developed nuclear fission (splitting the atom); is often credited with coining the terms 'wormhole' and 'black hole' (although technically the latter was coined by an audience member at one of his lectures for NASA).
Hugh Everett - The man who began explaining quantum physics in terms of multiple worlds/parallel universes; earned the scorn of many quantum physicists, including Niels Bohr; left the scientific/theory world to concentrate on warfare and weaponry.
Bryce Seligman DeWitt - Expanded upon Everett's theories and gained them some credit.
Neil Turok - Proposed that the 'big bang' was actually the collision of two parallel universes, explaining the pattern of irregularities that exist throughout 'our' universe.
Max Tegmark - Has began classifying the various 'multi-verse' theories and consolidating Schrodinger, Bohr and Everett's theories into one, beginning with "Quantum Suicide" and "Quantum Immortality" thought experiments; has provided mathematical arguments for the 'multiverse' theory; has attempted to classify all parallel universes.
Edward Witten - Creator of the "M-Theory" which describes 11 dimensions.
Louis Crane - Quantum gravity researcher; deep space travel thinker.
Lee Smolin - Physicist concerned with quantum gravity and string theories; looks at quantum physics in terms of biology and "natural selection"/evolution.
All of the above - Trying to bring about Albert Einstein's "General Theory Of Relativity" and merge with quantum theory to bring about an understanding of, basically, everything.


Those Theories
In Brief


Quantum particles exist on such a small scale they don't even conform to normal laws of the world of physics - in short, anything is possible!

Every possible version of every possible atom cannot possibly be contained within our world, so to make quantum physics possible, we need several universes.

There are various theories dealing with these multiple universes - none can be proven correct or incorrect at this point in time.

These infinite and unknown possibilities has led to many a great sci-fi imagining, including the TV show Lost.


Fin

So, there you have it. If you want more info, Google the above names, theories or simply "quantum mechanics" - I guarantee you won't find anything written in a more straightforward, down-to-Earth way, however.

If you enjoyed this article, I have more coming, so stay tuned! Hopefully I can refine this even further in a more simpler to understand manner.

Please leave a comment telling me what you thought - the good and the bad, please.

2 comments:

  1. Dude that must have taken you a while. Good stuff though. I've read a lot about quantum mechanics but like Einstein I'm more of a relativity guy for the same reasons...I don't like the chance aspect. Anyways, one thing you are missing: the grand unification theory. The theory that says all forces in nature are really one force and thus the same rules of physics apply to them all. This would mean the rules of quantum do govern classical physics, E&M and relativity...

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