🚀 go-pugleaf

In article <3hc5lq$l79@cwis.isu.edu>, Eric Rude <rudeeric@cwis.isu.edu> wrote:
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)
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)Hello
)Here are some questions from some high school students:
)1. If there is no animal life present (intelligent or otherwise), when 
)the sun rises, is there color?

Consider what happens when you take a picture with a color camera.
If you are an Animist Copenhaganist, you might insist that the
picture is in a superposition of states until an animal looks at it.

More probably, you'll accept that cameras take pictures of color even
without an animal present.

If you are a Thermodynamic Copenhaganist, you'll insist that as soon as
something irreversible (involving thermodynamic processes)  happens
that it's "real".  (Of course, you'll probably waffle a bit
about what irreversible really means :-) ).  This is my own position.

An MWI advocate (Multiple Worlds Interpretation) would insist that you
become correlated with one particular picture when you observe it, but
that all possible pictures (along with all possible versions of you
looking at them) exist in at least some metaphysical sense.

)2. Is it possible (theoretically or otherwise) to split a photon? If so, 
)what would it result in?

It depends on what you mean by "split".

There are some interesting experiments involving non-linear optics which
"split" a higher energy photon into two lower energy ones.  But all of
them are complete photons.

There is another sense of "splitting" used to describe the behavior of 
photons in between times when they are observed, also known by the
technical term "superposition".  I'd suggest reading QED by Feynman
or "Quantum Mechanics and Experience" by Albert for more details
on this.  Feynman describes how photons act as if they 
took "all possible paths", and Albert talks a bit about superpositions.
I'd recommend reading Albert's Scientific American article in addition
to the book - he's more concrete and less abstract in the former which
may help understand the later.  The abstraction is likely to turn off
readers who aren't familiar with at least one example of the abstract
behaviors he talks about (IMO).  Neither uses advanced math.

However, any observed photon is a complete photon - there's no such thing as observing
as *observing* half a photon.  Another way of saying this is that
photons appear to be fundamental particles (unlike atoms, or
even protons or neutrons).