Thursday 9 July 2009

Superposition

Superposition:
The fact that quantum systems, such as electrons and protons, have indeterminate
aspects means they exist as possibilities rather than actualities. This gives them the
property of being things that might be or might happen, rather than things that are.
This is in sharp contrast to Newtonian physics where things are or are not, there is no
uncertainty except those imposed by poor data or limitations of the data gathering
equipment.
The superposition of possible positions for an electron can be demonstrated by the
observed phenomenon called quantum tunneling.



Notice that the only explanation for quantum tunneling is if the position of the electron
is truly spread out, not just hidden or unmeasured. It raw uncertainty allows for the
wave function to penetrate the barrier. This is genuine indeterminism, not simply an
unknown quantity until someone measures it.
It is important to note that the superposition of possibilities only occurs before the
entity is observed. Once an observation is made (a position is measured, a mass is
determined, a velocity is detected) then the superposition converts to an actual. Or, in
quantum language, we say the wave function has collapsed.
The collapse of the wave function by observation is a transition from the many to the
one, from possibility to actuality. The identity and existence of a quantum entities are
bound up with its overall environment (this is called contextualism). Like homonyms,
words that depend on the context in which they are used, quantum reality shifts its
nature according to its surroundings.

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