Re: Experimental Evidence for Special Relativity

On Oct 18, 3:02 am, John Kennaugh <J...@xxxxxxxxxxxxxxxxxxxxxxxxxx>
wrote:
PD wrote:
On Oct 17, 4:18 am, John Kennaugh <J...@xxxxxxxxxxxxxxxxxxxxxxxxxx>
wrote:

The photoelectric effect *cannot* be explained by continuous wave theory
because continuous wave theory says that the energy spreads out evenly..
If it spreads out evenly then there is no possibility of it arriving at
a point with sufficient energy to knock an electron out of an atom. Wave
theory fails. Now Take an experiment which you would claim shows it
cannot be particles. The double slit experiment.

If the light level is reduced such that photons arrive singly at a
double slit, interference fringes are detected, it is claimed that
'interference' still takes place. I beg to differ. Not as I understand
interference at any rate. If two sine waves each amplitude unity are
interfering with each other then depending on the phase, the result is
anything from an amplitude of 2 to 0 and *any amplitude in between* e.g.
an amplitude of say 0.333 is perfectly possible.

No, this is incorrect. An interference pattern does not demand a
continuous intensity distribution.

How do you define 'interference pattern' other than a pattern which
results from the process of interference. The process of interference
requires that two things 'interfere' i.e. two things partially
cancel/reinforce each other. What is produced in this instance may mimic
interference but it is not the result of interference.  What it is in
this case is directional modulation not interference.

Sorry, no. An interference pattern is an observational phenomenon. It
is a series of maxima and minima. It *suggests* the presence of things
interfering, because the same pattern is found in other cases where
there is something clearly interfering, but you do NOT need to
establish the existence of things interfering to call the
observational phenomenon an interference pattern.

In the case of particles fired one at a time through a grating or a
dual-slit screen, what is observed on the other side is clearly an
interference pattern, regardless whether you can lay your fingers on
the things that are interfering. The presence of this pattern then
*leads* you to surmise that there are things interfering.


I don't know where you would have
ever gotten this idea. Yes, the interference pattern is "lumpy" at the
level of individual photon energy deposits. This indicates that the
particle nature of light is indispensable.

Light is made of particles.

No, I disagree. Light exhibits particle properties. This does not
allow you to conclude that light is made of particles.


However, the fact that
there is an interference pattern *at all* when the photons are emitted
one at a time is also remarkable.

Agreed.

This indicates that the wave nature
of light is indispensable.

Not at all. The physical process called interference requires that two
things interfere (partially cancel or reinforce each other). This isn't
happening. What you have is the directional probability being described
by a wave function. If I am travelling along an undulating track
shooting a machine gun at a wall the position traced by the bullets will
form a wave. That doesn't mean the bullets must be considered as waves.
It is the process determining the direction they travel which causes the
wave phenomena.

The question is 'when a photon goes through a slit what determines the
direction it will take and how does the presence of the other slit
change that'.

Add to that another very important question:
'if a single photon's direction is modulated in such a way as to produce
a facsimile of an interference pattern how is it that on mass photons do
not produce a pattern if they are not coherent?'. Clearly there is a
process which can be disrupted.

This is precisely the lesson afforded by
this real experiment -- that light exhibits *both* the qualities of
categories that up until 75 years ago, we thought were mutually
exclusive. This mutual exclusivity, it appears, was the result of
*our* categorizing phenomena known up to that point into distinct and
nonoverlapping camps, from which we concluded that things could be
waves or particles but not both. Then light revealed itself to be
something unlike anything else we had seen before and resisted this
categorization. It takes a stubborn mind to refuse to admit that light
can be something completely unlike what we had encountered up until
that point and to insist that it MUST fit into one category or the
other.

Many months ago Tom Roberts informed me that photons were point
particles with no internal structure.

Actually, we don't firmly know that either, at least not
experimentally. They may be treated that way in some models -- that
is, the object in the *model* may be treated as a point particle with
no internal structure. I think he'd be the first to agree with that
statement.

I have just read that QED says
they are standing spherical waves. That at least is a move in the right
direction - photons must be dynamic to produce wavelike phenomena -
although it does involve reinventing the aether for them to be waves in
(not of course that anyone will call it aether and not of course that
physics ever really got rid of it in the first place).

Waldron suggests that a photon contains opposite charges and that it
rotates. Whatever else Maxwell's equations show, they show there is a
link between charge and light, between charge and photons. Maxwell's
equations relate to relationships which relate to charge and nothing
else.

When such a photon passes through a slit then one variable is the
position of it w.r.t the slit middle, near one side, near the other.
Another is its orientation w.r.t the slit (it has a positive side and a
negative side). We have the field caused by the rotating charge which
can potentially affect both slits. We have the much higher numbers of
photons which do not pass through the slits which may 'prime' the slits
in some way, a process which can be disrupted if photons are randomly
orientated as in non coherent light. It falls way short of an
'explanation' but it shows that there are a number of variables to work
with.

As I say it is impossible to explain the photo electric effect using
waves but no one has proved you cannot explain wavelike phenomena with a
suitable particle model.

And you are welcome to try. Until then, there is nothing intrinsically
wrong with identifying light as something that resists categorization
into *either* a particle or a wave nature but not both.

PD
.

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