MWH+Theory



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Hugh Everett
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[|Hugh Everett], depicted above, is the founder of the many (or multiple) worlds hypothesis theory. He came up with the original idea one night while he was talking with his friend about "ridiculous things about the implications of quantum mechanics." In the following weeks this idea grew into a more developed theory. Everett didn't like how the rules of quantum mechanics only applied in a mathematical world, not in the one people inhabit.

Before Everett's theory, the accepted reason for this exclusion of the macroscopic world was that it was simply separate from the microcosm. Cornell University physicist N. David Mermin explained it this way: "Quantum mechanics is a device for enabling us to make our observations coherent, and to say that we are inside of quantum mechanics that quantum mechanics must apply to our perceptions is inconsistent." This approach is called the Copenhagen Interpretation. When Everett's student adviser, John Archibald Wheeler, took a copy of his student's thesis to some of the big names of quantum physics, Bohr and Peterson, and Alexander W. Stem, they dismissed it and called it theology, not science. Wheeler was hesitant to confront the famous scientists and argue for Everett's ideas, and ended up writing them a nearly apologetic letter. In the letter he stated that the theory wasn't trying to change quantum mechanics, just expand on it. But Everett didn't agree with that at all. He replied that "The Copenhagen Interpretation is hopelessly incomplete because of its a priori reliance on classical physics...as well as a philosophic monstrosity with a "reality" concept for the macroscopic world and denial of the same for the microcosm."

Everett later took a research job at the Pentagon in order to avoid being drafted. Wheeler convinced him to eventually publish a much-shortened version of this original thesis, but it didn't get much attention. Everett continued to work in the government and founded his own company, but never returned to quantum physics.

Eventually, people started to look at his ideas seriously. There are still many people who don't agree with the theory, but most people do find it to be a mathematically sound explanation. "When I think about the Everett theory quantum mechanically, it is the most reasonable thing to believe. In everyday life, i do not believe it." Many scientists agree with this-they just don't think that the branching possibilities seen in universal wave functions represent actual realities that exists. Others, like Sir Roger Penrose, think that gravity is what keeps these alternate universes from splitting off from this one. Others do believe in all parts of Everett's theory. David Deutsch, a theoretical physicist, has based much of his work towards building a quantum computer on this theory. "All possible events, all conceivable variations on our lives, must exist, says Deutsch. We live not in a single universe, he says, but in a vast and rich 'multiverse.'"

In any case, Everett started the discussion that will probably continue for many years to come. As his student adviser said, "The questions he brought up were important."

Importance

 * The Many Worlds Hypothesis revolves around the concepts of measurement and outcome. When there is more than one possible outcome, we can only observe one possible outcome, not a combination of them What about the other possibilities? What causes us to get the answer we do when we make an observation? In a nutshell, the question that Everett addressed was: **How and why does the unique world of our experience emerge from the multiplicities of alternatives available in the superposed quantum world?  Everett's concept of multiple universes eliminates this problem. . The notion that at each observation the universe splits as to repeat each and every possible outcome is the conclusion to which Everett came.In a documentary titled "Steven Hawking's Universe: An Answer to Everything", [|Darwin's Theory of Evolution] is related to the Many Worlds Hypothesis. The question proposed applies Darwin's Theory of to the development of the universe. what if the universe undergoes the same evolutionary process as living things? The video explains how Darwin's theory explains that the abundant variety we see among living organisms is the result of a rational process: [|Natural Selection] . Darwin was able to explain something that most saw no logical reason for. The Multiple Worlds Hypothesis is similar in that we long have accepted outcomes as they are, as a result of chance, but we are beginning to advance ourselves beyond that. "Steven Hawking's Universe: An Answer to Everything" describes the universe as a complex self organized system, the result of a natural process. This notion, and the thought of the Many Worlds Hypothesis as a whole is far from being proven, but it is an important step towards understanding the world in which we live.

Chemical Explanation of Many Worlds Hypothesis
The Many Worlds Hypothesis was created at an alternative to the [|wave function] collapse of the Copenhagen interpretation. In order to understand the Many Worlds Hypothesis, it is important to understand the idea of the wavefunction. A wavefunction is the simultaneous existence of all of an objects possible states. With the widely accepted Copenhagen interpretation, a quantum particle, or quanta, exists in all its possible states until a measurement of the quanta is taken, at which time the quanta "collapses" into one of its states, the state which is observed. This assumes that the quanta did not exist in this state until it was observed. The MWH, however, assumes that the wavefunction always follows its "wave equation" and therefore can exist in the same state independent and regardless of observation. In fact, it looks at the entire universe as a single physical system, having its own infinitely complex wavefunction (Note that in Everett's terms, the universe is the combination of all the split worlds, so the physical system described is all the split worlds together). When a quantum particle interacts with something, the universe divides so that that particle may continue to exist in all forms of its wavefunction, albiet in separate universes. Every possible outcome of the interaction ends up being represented. .

The "splitting" of the universe is not some cataclysm cosmic event that is even noticeable, rather it can be thought of as a branching, where one possible reality goes one way and one possible reality goes another. This explains why although infinite possibilities exist, we only experience one.This branching results in an enormous amount of realities, possible infinite, for every interaction in this universe or any parallel universe. Simply stated this means that whenever anything in the universe comes to an impasse, both or all possibilities occur but in separate universes. Atoms and molecules are interacting always. Since the Many Worlds Hypothesis proposes that all possibilities are presented, only in different universes, it is suggesting that there are an unfathomable amount of parallel universes, and countless more being produced every millisecond. Where are these universes? What is the force that causes them to be? Is there any tangible evidence? These are the questions that scientists ask themselves everyday. Although the Many Worlds Hypothesis has yet to be backed by hard evidence, it has yet to be disproved, so it is in the consideration of many.

Schrodinger's Cat
Schrodinger's Cat is a thought experiment that is often used as a demonstration of the Copenhagen interpretation, which is ironic because the experiment was originally proposed to poke fun at the Copenhagen interpretation. The experiment can also be used as demonstration of the MWH, the alternative to the Copenhagen interpretation. The experiment is simple: a cat is placed in a box with a lump of radioactive material. If the material emits a particle, the particle will be recorded by a device that will then release a poison into the box, killing the cat.

[[image:http://www.babble.com/CS/blogs/strollerderby/2009/11/800px-Schrodingers_cat.png width="717" height="388" align="center"]]
Since its impossible to know whether the particle will be emitted, its impossible to know whether the cat is alive or not until the box is opened. In fact, the Copenhagen interpretation would imply that the cat is neither alive nor dead but a superimposition of both, until the box is opened at which time the system collapses into one of its wave function states (alive or dead). The MWH suggests that at any point a particle could be emitted, the world branches off into two realities, one where the cat lives and one where it dies. The observer has no affect on the system, so essentially the observer is just carried along for the ride when the universe splits. This allows the MWH hypothesis to offer an alternative to the idea of the observer who defines the system in the Copenhagen interpretation.

[[image:http://static.howstuffworks.com/gif/quantum-immortality-1.gif align="right" caption="http://static.howstuffworks.com/gif/quantum-immortality-1.gif"]]
First it should be stressed that Quantum Suicide is a thought expiriment. **DO NOT TRY THIS AT HOME**. The idea behind Quantum Suicide is, like Schroedinger's cat, based around quatum probabilities. But instead of a vial of poison, this man holds a gun. The gun has a device that measures the spin of a quark, a small quantum particle. A quark can be either spin up or spin down. If this device finds the quark to be spin up, the gun will just click. If the quark is measured as spin down, the gun will fire and the man will die. The man fires. The universe branches in two, one where the quark is spin up and one where it is spin down. The spin up man survives, the spin down man does not. The man fires again, and the same series of events transpire. To a bystander in one of the universes, at some point the man will die. But to the man, the gun just keeps clicking, forever, in a theoretical phenomenon called **Quantum Immortality **. This idea may seem odd because to people in this universe, death is final and irrefutable. But with the Many Worlds Hypothesis this universe is just an offshot of an infinite number of universe splits behind us. In this universe, this man just died, but in some parallel universe, he's still alive and pulls the trigger again. Since he can't perceive his own death, he is only going to perceive the universe in which he lives. And lives, and lives. Quantum immortality suggests an interesting idea: does anyone ever die? If someone dies in a car crash, friends and relatives would mourn them and then move on, and that persons time as a conscious being would have come to a close.But if the Many World's Hypothesis is correct, that person saw the other car coming and then swerved away. They lived their life out. They can only percieve the situation in which they died, as could anyone. This would imply that consciousness could survive through all dangerous experiences, though it might be percieved by others as death. It is also impossible to disprove this theory. All people know about death is from their experiences of seeing other people who, in this universe, die. If the MWH is true, every conscious organism will survive every near death experience it ever faces unless there is a statistical impossibility of survival, in which case there would be no other reality except death.

Many Worlds Mario
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In the video above, the well known video game "Super Mario" is used to portray the concept of the **Many W​orlds Hypothesis. Every time Mario performs an action that could have multiple outcomes, he is multiplied. Each 'version' of Mario then experiences a different outcome. The Marios cannot interact with each other because, while the universe splits into many possible outcomes, each Mario perceives only one. The video doesn't show the actual splitting of universes but in order for the Marios to interact they would have to perceive an infinite amount of universes all superimposed on top of each other! **

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