Stephen A. Lawrence wrote:
>
>
> [EMAIL PROTECTED] wrote:
>> Michel Jullian wrote:
>> > A wave packet coalescing into a point-like particle when it hits
the screen, yes that's about as close to common sense understandability
as it can get. Makes one realize the wave aspect of particles is a hard
fact.
>> >
>> > http://en.wikipedia.org/wiki/Double-slit_experiment
>>
>>
>> Any QM expert can correct any possible errors, but here's how I've
understood the double slit. Both slits are open. Before the single
photon even emits it must decide which hole it is going to go through.
To accomplish this task it is understood that the photon "plays out" the
entire process before hand, like some theatrical play. This is called
the wave function. So instantly the wave function traverses the path,
travels through both slits, and hits the detection screen, and from
there decides what path the photon will take. Supposedly the wave
function traverses at infinite velocity as if there were no time.
>
> Wheeler's delayed choice experiment shows pretty clearly that it
doesn't work that way -- you can change the target after the particle is
in flight, even after it's "gone through" the slits
To understand my interpretation you need to think in 4-dimensions. What
you said clarifies exactly what I said. Again, it appears the idea of
the photon traveling through space is invalid. Lets step through the
experiment -->
We'll refer to the appearing mirror as D.
1. D is removed.
2a. At t=0 the photon is emitted.
2b. At t=0 there's a wave function for the photon. The wave function
spreads out and extends into the *future*. You can think of the future
as a dimension.
3a. At t=1 D is activated.
3b. At t=1 there's a wave function for D (for simplicity we'll refer to
it as one function). Note, the photons wave function (from step 2b,
above) crosses this wave function.
3c. Photons wave functions collapses when it senses D's wave function.
4. At t=2 the photon strikes D.
In a nutshell, the wave function spreads across space, without the time
aspect, like tentacles extending out in time. The mirror, D, is also
made of matter that has wave functions. Do you understand it now? So
the wave functions from both the photon and the mirror decide, by
so-called laws of probability, what will take place. What occurs is
merely a result of that decision / probability.
> , and change whether you get an interference pattern or not: at the
very last femtosecond, replace the screen with a pair of telescopes that
let you tell where the flash came from; do this for every particle, and
the interference pattern vanishes. This experiment has been done.
And it's in agreement with what I said.
> You can replace the screen with the telescopes just before the
particle hits the screen and it has the same effect as replacing it
before the particle takes off. If the particle "made up its mind" before
it took off, and hence physically traversed one pre-determined slit or
the other and arrived at a pre-determined point in space where it
"expects" the screen to be, the experiment would not work as it does.
No, you're still thinking in terms of 3-dimensions.
> In any case, if it were to prescan the path as you suggest,
information would need to flow from the target to the particle
"instantly", which violates the speed limit of C and hence causality in
a relativistic universe. I.e., some observers would see the information
traveling backwards in time.
The interpretation doesn't work that way. The wave functions (plural)
make the decision, like rolling dice. The actual particle does not
arrive at its destination faster than c. It's the wave function that
instantly spreads, but the wave function is not 3-dimensional physical
object.
[snip]
Regards,
Paul Lowrance
