Re: To AC -- on electrons

On Mon, 12 Jun 2006 02:27:22 GMT, Zoe <muze10@xxxxxxx> wrote:


Maybe you can answer some questions I have about the wave-particle
duality of photons.

First, if a wave needs a medium in which to travel, how do photons
travel through a vacuum in which there is no medium for a wave to
travel? Do they change and act as a particle when passing through a
vacuum?

Also, in the double-slit experiment, it seems that when photons are
fed through a double slit, one at a time, with a detector to keep
track of which slit each goes through, there is no interference
pattern on the other side. Yet, without the detector, there is an
interference pattern.

The Copenhagen interpretation says that until the particle is detected
at any location along a probability wave, it actually exists at every
point, therefore it will pass through both slits, resulting in an
interference pattern. Tell me, please, is it possible for an
indivisible particle to divide and pass through both slits at the same
time?

Having come up against that oddity, I find myself speculating. Bear
with me.

What if the interference pattern, suggestive of a wave, is really due
to an optical illusion, something that the human brain gets tricked
into seeing? Since keeping track of single photons keeps the
interference pattern from developing, then maybe the wave-like
interference pattern is a result of the brain's inability to keep up
with the high-speed movements of the photons? I mean, if you don't
keep track of the photons, they move so fast and pile up so fast that
they leave the illusion of light and dark fringes? Which would mean
that photons or electrons are really only particles, never waves? The
wave-like pattern is only in the eye of the beholder?

Okay, I know I'm probably way off in left field here, but hey, it's MY
sandbox. I remember looking at a ceiling fan, and the blades were (as
usual) a blur, appearing as just a single, solid, rotating circle.
But if I followed the movements of the blades by rotating my head in
sync with the movement of the blades (yeah, I know this sounds loony)
I could once again see the individual blades of the fan.

So, could it be some form of relativity going on with the observations
in the double-slit experiment? The same way the movement of the
blades blur or separate relative to the stillness or parallel
movements of the observer, likewise the high-speed movement of photons
appears to produce interference, relative to the still position of the
scientist?

Your left field is pretty much in the same location as everyone
else's. The problem is that people look at quantum mechanics through
the rose-colored glasses of familiarity with classical phenomena of
experience with large objects that don't show those effects. So the
quantum-mechanical effects defy experience and become hard to grasp
conceptually.

First, the "wave" notion is a metaphor for a disturbance that
propagates at a certain velocity. In the case of classical
electromagnetism, it is the electric and magnetic "fields" that
wiggle. As Michelson and Morley showed, to much consternation in the
world of physics, there is no "ether" to act as a medium. Particles
like photons, of course, don't have that problem and relativity solves
the constancy of velocity problem. Light does not "become" a
particle under some circumstances and a wave under others. Rather,
the notion of a particle is appropriate for describing it under some
circumstances and the notion of a wave is better for describing it
under others. But what light really IS is another situation that is
simply not an intuitive notion. It is what it is and we have tools to
describe its behavior in all instances that we have found, sometimes
using wave-like methods and sometimes using particle-like methods as
needed.

Light (photons? waves?) ALWAYS shows interference as long we have some
means of detecting what happens. If there is absolutely no way of
telling whether or not it shows interference then there is absolutely
no way of knowing what it does. But if you try to set up an
experiment "without detectors" but then later cheat and peek into what
happened, the light "knew" you were going to look and interfered with
itself. Even a single photon "knew". No, that is not the proper way
of explaining things, but it will do.

When I took quantum mechanics, the professor told us (paraphrasing
some famous physicist whose name I forget) to forget our ideas and
stop thinking and just believe the mathematics. Set up the
foundations in a mathematical form and go with the math. It predicts
what happens and experiment confirms it. That is about all we can say
about "reality".

And no, some of the ideas really don't make sense. But when you do
the experiments, that is really what happens!


.

Relevant Pages

  • Re: nature of electrical influence
    ... >> How does emitting photons create an attraction? ... my model excludes photons as having localized particle ... photons are purely wave phenomenon. ... >> electrons, if the waves have the same frequency, but are out of phase ...
    (sci.physics)
  • Re: nature of electrical influence
    ... >>> How does emitting photons create an attraction? ... my model excludes photons as having localized particle ... photons are purely wave phenomenon. ... >>> electrons, if the waves have the same frequency, but are out of phase ...
    (sci.physics)
  • Re: Is this what a "wave" is?
    ... >> The water wave analogy still applies as well. ... i.e. to the motion of the B field past the particle. ... It appears clear to me that photons can and do ...
    (sci.physics)
  • Re: OT - Global Warming Revisited
    ... >>>Yet particle experiments in powerful colliders reveal that photons behave as though ... >> theory of quantum mechanics, we can explain the behaviour of light ... >> tend to describe light as a wave. ... Light is described in terms of particles called photons." ...
    (alt.machines.cnc)
  • Re: attractive force via particle exchange - how?
    ... >> Yes, but the point is that the disturbance, the wave itself, the ... attributable to a multitude of photons spreading outwards in all ... What we know is that neither a particle nor a ... as required by momentum conservation. ...
    (sci.physics)
Loading