Monday, October 24, 2011

The Interpretations of Quantum Physics

The following interpretations are theories to explain what is really going on behind Quantum Mechanics. Each theory has unique basic concepts and they are not necessarily mutually exclusive since there is some overlap of concepts.

Schrödinger's cat is a thought experiment involving placing a cat in a sealed box with a vile of poison that would kill the cat if broken, a radioactive material and a gaiter counter set to drop a hammer on the vile of poison if it detects a radiometric decay event. The cat is later observed it is found to be ether alive or dead and each these interpretation has a different description of the state of the cat before it is observed.

Accirding to the Copenhagen interpretation a quantum particle does not in any one state but exists in all of it’s possible states at once. A soon as a quantum particle is observed it is essentially forced into one of the possible states and that is the state that is actually observed. Since it may be forced into a different state each time is why quantum particles behave erratically. The state of a particle being in all possible states at once is called an object's coherent superposition. When an object is observe the superposition collapses the object is forced into one of the states of its wave function. Schrödinger's cat i s seen as both dead and alive at the same time until actually observed. Ultimately the only thing that really matters are the experimental results it does not really seek to explain what it happening behind the experimental results. Currently it is the most popular interpretation, but it is losing ground.

The consistent histories interpretation was put forward by Robert Griffiths in 1984. It works backwards from the result of an experiment and says that only a few possible histories are consistent with quantum mechanics and that Quantum mechanics simply predicts the probabilities of various alternative histories Schrödinger's cat is either alive or dead but not  both Quantum mechanics just gives the probability of which it may be. This idea is not very popular because it still doesn't explain how a particle can go through two slits and interfere with itself and it is considered by some to be pretty much the same as Copenhagen.

The Transactional interpretation quantum mechanical waves as stand waves in space time that constructively interfere were the particle is  and destructively interfere every place else. These waves go both forward and backward in time. There is an "exact canceling" of waves so that is no "net" energy travels backwards in time. In the case of Schrödinger's cat tt is alive until the interference patterns line up in the sample to result in a decay event.

The Bohm interpretation or pilot-wave theory as it is also called depicts the quantum wave guides the particle. It is totally deterministic and good at explaining quantum phenomenon but requires a large number of hidden variables that can not be directly measured. The hidden variables have the side affect of rendering the interpretation untestable. Schrödinger's cat is alive until one the pilot-waves in the sample to causes a decay event.

The many-worlds interpretation sees the world as constantly splitting off into multiple universes in which every possible quantum event occurs. This fits perfectly with Evolution even the most improbable events occurred in some of these universes. With Schrödinger's cat the universe keeps spitting off into each alternative in one the cat lives and in the other dies. They both happen in different quantum universes. There is no evidence for it since the alterative worlds would be forever out of reach. While quantum interference between adjacent worlds has been suggested, the possible evidence for it. Successful interpretation of single particle interference is not unique to the Many-worlds interpretation. So acceptance of this interpretation is purely philosophical and not scientific since it can not be tested.

With the consciousness causes collapse interpretation consciousness causes collapses the quantum mechanical waves as a resuly of observation. There is supporting evidence for this though the evidence is not exclusive to this interpretation. It is compatible with General Intelligent Design as well.  This supporting evidence comes from the human brain. It turns out that synaptic activity in the brain requires quantum tunneling on demand. This shows some degree of control by the mind of quantum wave functions.  Thus view works with both New Age / Hinduism, and the Christian world view. With New Age / Hinduism it provides a way for the mind to interact with the world beyond the five senses. With the Christian world view, since God is the ultimate mind it provides a model for his interaction with our world.  Schrödinger's cat would be both alive and dead until observed then the mind of the observer would collapse the wave function choosing one or the other. It is similar to the Copenhagen interpretation in this regard.

General Intelligent Design also known as General Grand Unification (GGU) sees the waves and their collapse results from intelligent agents that determine the states resulting from the waves' collapse. These intelligent agents could be one or more intelligent beings or mechanisms preprogrammed by an intelligent being.  This is supported by evidence of synaptic activity in the brain requiring quantum tunneling on demand showing some degree of intelligent control of quantum wave functions. This interpretation fits well with the Christian world view. The idea of an intelligence controlling the universe at its fundamental level fits well with God as described in the Bible. In the case of Schrödinger's cat, the cat is a live until the controlling intelligent agent decides to cause a decay event to takes place and then the cat dies.

Theew is a demonstraitablre relationship between the mind and Quantum Mechanics that provides evidence in support for the last two interpretations consciousness causes collapse and General Intelligent Design. It turns out that the synaptic barriers of dendrite brain cells are too thick for nerve signals to classically cross. This means that nerve signals need to use Quantum tunneling to cross the dendrite synaptic barrier. The odds of the nerve signal tunneling across the dendrite synaptic barrier are 1 chance in  10,000,000,  Yet for our brains to function these tunneling events need to occur on demand this is evidence for the mind being able to control quantum phenomenon and against the naturalistic model of the mind as well.

In conclusion there are many ways of interpreting Quantum Mechanics. Acceptance or rejection of each often has more to do with philosophy than science. each fits better with some philosophical views than others and each interpretation differs in how it sees the fundamental nature of reality.

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