Problem with the two slit experiment, Observing later

Hi Good Elf,

Oh dear. What a waste of a good ripple tank ( http://www.echalk.co.uk/Science/Physics/ri...Tank/ripple.htm ) ..what has clearly failed to become clear is that intensity is (loosely) given by the square of the height of the waves passing at any particular point .. actually the RMS value would be better .. the waves move but the intensity is static .. maybe ripple tank Mk2 will have a button for 'Show intensity'. Belatedly :- where the surface is undisturbed .. those are the interference minima .. in general the brighter the waves passing a particular point -> the greater the intensity or, in the case of the single photon DSE, the greater the chance of detecting a photon at that point.

Lisa's applet ..( http://www.hmi.de/bereiche/info/dualismus/exp.java_en.html ) .. assumes the waves arriving at both slits are of the same phase and is intended to show how the intensity (the chance of detecting a photon) varies as the two paths vary from being in phase (maximum constructive interference) to 'out of phase' where there is maximum destructive interference.

By failing to apply a rigorous interpretation I think we both hoped they would be equally useful whether interpreted as waves, cavities or wavefunctions. It seems the result is that both were a complete waste of time .. sorry.

The DSE equation ( http://schools.matter.org.uk/Content/Inter...ce/formula.html ) gives you everything you need to know to understand (or ignore) either or both of the above.

The DSE equation (and the others) clearly indicate that there is interference between waves from different 'waves' (technically phase difference > 360 degrees) .. if you wish to interpret this as (by definition) showing a photon has the properties of a ray .. then a photon quite definitely has the properties of a ray .. all you need to do is look at the geometry ( http://schools.matter.org.uk/Content/Inter...ce/formula.html ) and results ( http://www.teachspin.com/instruments/two_s..._combiplot2.gif ). After looking at the results for some time I have to conclude that the explanation will involve something far more subtle than any sort of pulse

We all have to accept that there may be people 'out there' with a greater understanding of the problem than we have. I hope we would all be willing to allow them a chance to increase our understanding without first subjecting them to a full and repetitious account of our views and theories. As we have just found out.. one person can see a solution to the problems as they see them while other people may be looking for a solution to a totally different set of problems.

Best wishes,

-C2.

This post has been edited by Confused2 on Jan 25 2007, 09:30 PM

Funny story, I finally found time last weekend to get somewhat caught up on this thread. I was going to post on Monday (but ran out of time and couldn't) that I thought you guys were arguing about the same thing but from different angles... I even had this cute analogy involving dust piles and Ed Witten..... But now in catching up over the last couple of days, you guys figured it out yourselves.

YIPPEEEEE!!!

Hi Laserlight, Confused2, Montec, "THEY", Aerohead, TRoc, Fivedoughnut, Yquantum, Neil et al,

OK... Maybe I should actually point out what I mean exactly using this ripple tank applet...
http://www.echalk.co.uk/Science/Physics/ri...Tank/ripple.htm

Start Applet, Tick "Stopped". Click "Clear waves". Choose "Setup double slit". Untick "Stopped" for 1/4 second or less. After that 1/4 second or less tick "Stopped" again. Choose second row control that says "No Sources". Unclick "stopped" again and let it propagate... See how the ripples propagate to the lower margin as a very short "pulse train of ripples". The crests and troughs pass all points on the way to the lower margin. Everywhere (no nodes anymore) except the dispersion minima actually gets equal maxima and minima so all points are exposed almost equally on the screen margin (as if a photographic film was there). This is fine for a ripple tank but it is not what happens with light. No matter how many photons are in that one pulse it does not emulate in any way what light actually does... its impulse response. In reality for a "real" coherent pulse of light you would get your "steady state" result for even the very shortest pulse... a single sync pulse (neglecting the point about each photon hits one point and builds up that pattern on a detector). If you were measuring intensity summed over time at the lower margin with a storage photomultiplier array for that one single pulse, a very large areas receive a near uniform "pulse" illumination. This is what ripple tanks actually do. This response for light differs from the response the applet has for steady state continuous wave. In the real world one single photon or one single photon wavefront will still produce your complete interference pattern "seeking all paths" ... you do not need to wait for the system to reach equilibrium. Only spatial coherence is required to build up the interference pattern, not temporal coherence (if such a thing could be defined). For a series of photons or photon pulses from the same distant source (even if separated by large gaps of time) some areas of the screen would not receive any illumination ever.... while others will receive illumination as successive maxima and minima only if allowed to reach equilibrium over some time. This applies also to intervening regions as well. They also have this existing standing wave pattern.

What we see is the third image with "advanced and retarded waves" producing standing waves and not the first or second image here...
+ =
It is the only "sane" resolution... Wheeler-Feynman Absorber Theory with the Cramer Transactional Interpretation of Quantum Mechanics as I have been saying. This gives the expected impulse response of the system. Ripple Tanks do not give this result since they only involve "retarded waveforms".

You can run the sequence again by Ticking stopped. Clear waves. Choose "one plane source, one frequency". Untick "Stopped" for 1/4 second. Tick "Stopped" after 1/4 second. Select "No sources". Untick "Stopped". Run to completion again. You should see this image as a single moving wavelet...

Click to enlarge... I have stopped it but in fact it will be moving and without other "waves" to interfere with will not have a standing pattern. This is crucial to understanding the DSE... absolutely crucial. Understand?

If you do understand and still disagree then we are unable to agree at all since I am using the observed experimental results and you are using something else.

Cheers

This post has been edited by Good Elf on Jan 26 2007, 12:07 AM

C2-

Hmmm, I disagree with this assessment. The intensity of the wavefront
follows the ISL, the frequency remains the same, the momentum stays the same,
and the energy of an individual photon remains the same.

A wavefront can only interfere with itself. In the case of a standing wave, the wave
is reflecting back on itself and will either constructively or destructively interfere
with itself. Remember, a wavefront has a fixed timing relationship to itself only.
Subsequent wavefronts have a different relative timing relationship that is delayed
by at least a wavelength in timing and spacial distance. (think back to your
radar days and the finned dummy load waveguide configuration, that was
designed to reflect the incoming energy back onto itself causing self cancellation
and heat generation)
In the case of a radar signal, the reflected waves crossed thru the transmitted
waves and were still returned to the receiver as the phase relationships of the return signals changed, but did not cancel as long as the phase was changing.

My point being that each wavefront only interferes with itself

Regards,
LL

GE,

I think the stop motion picture of the wavefront that you posted shows that the
cancellation and phase timing shift has already occurred in the immediate wall
vicinity just behind the slits. The advancing wavefront clearly shows how the
signal cancellation has caused phase and timing distortions to the advancing
wavefront. The advancing (and already distorted) wavefront just projects the
distortions onto the screen as the wavefronts expand. The non-cancelled energy
bands light up the bright intensity bands on the screen.

Are we in agreement on this point?

LL

This post has been edited by Laserlight on Jan 26 2007, 12:34 AM

Hi Laserlight, Confused2, Montec, "THEY", Aerohead, TRoc, Fivedoughnut, Yquantum, Neil et al,

I think so... but you need to duplicate the applet setup, as I have shown, to indicate the particular effect I am trying to show... the spreading without nodes and antinodes in the first couple of cycles. These defects themselves are not the antinodes, they can form antinodes as they merge to form a "bubble".

You can see here the static pattern of nodes and anti-nodes "illuminated" by the passing wave packet envelope. I am not specifically discussing Visser's Analysis (no such details appear on this applet). I am discussing just what way the wave-tank does not emulate light... the most important aspects that are not shown by a simple wave tank that is programmed on a simple "Real Number" model of the waves interfering and mixing with themselves.

If you look at the defect animation you will see that these defects extend...
Click on Figure 4 or click here...
http://www.opticsexpress.org/view_media.cfm?umid=3815
Click on Figure 6 or click here...
http://www.opticsexpress.org/view_media.cfm?umid=3816
These animations are able to be saved as gif's. The second shows a field of spreading defects "periodically" filling space to the edge of the gif boundary... and obviously beyond but not shown. As the slit widens, each side a mirror symmetric image of the other side of the slit. Also importantly is the first illustration which shows how the defects "merge" as the slit is dynamically widened to produce "super-brightening" in the residual zone if everything is correctly arranged. See how the defects stream out from source at critical spacing and obviously other super-bright patches cannot be shown in this less detailed illustration... Fig 6.

As far as I can tell these defects extend to "infinity" well beyond the boundary of the gif image. The defects are of great importance near the actual slit especially when the slit is narrow. The super-bright (anti-nodes) zones continues to widen and form optical images on a screen of the external world as "pinhole cameras" within the envelope of defects which are along the margins of the widening aperture. These defects will continue to infinity if allowed but initially when the slit is exceedingly narrow they only appear as evanescent features near the slits and then they suddenly string out to infinity as far as the gif boundary permits. Clearly they are part of the issue of spatial packet frequency dispersion (packets are made up of more than one frequency and this extra frequencies lead to the defects as well). There are unseen nodes and anti-nodes throughout the space not represented at all. Aside from the topological charge these are already known to be the result of Orbital Angular Momentum (OAM)... also not discussed or dealt with. Remember this?
Optical Analog of Uncertainty Principle
This is where the spin comes in. There are two types of spin and one of them is OAM which is the symmetric packet orbital rotation as opposed to axial packet rotation... the Isospin. Because of Boson states the photons all have some of each. Only OAM can be zero but a photon must always have Isospin. So we have charge, spin and parity all occurring within the one packet (a single event)... Interfering with itself, resulting in all of this.

A lot is going on in these spaces with the refractive index as well. That is also not specifically shown and that point is extremely important... maybe the most important. Just recall that optics and electromagnetism does not allow for these defects in the first place to solve this array you need to "anomalously" introduce them. What this is saying is "Missing Theory Here... please insert". This is a null boundary. Some people are saying nothing is needed because this is a null. I would say not true... I have discussed why already.

Cheers

This post has been edited by Good Elf on Jan 26 2007, 04:15 AM

GE, C2, and All,

GE the morphology of the advancing wave is a direct byproduct of its interaction
with the matter and geometry of the slit(s). This is best illustrated by the varying
degrees of diffraction that is observed depending on the width of the slit(s) as well
as the separation of the slits.


The paper "Plasmons at Work?" presents some intriquing surface interactions
that have a profound effect on the cross signal mixing that takes place in the
environment just beyond the slits.

Look at the rear side of the slit wall in the illustration and think about the
mesomechanism that are theorized in this paper. IMO, plasmon "density"
and their ability to influence an impinging EM wave is directly correlated to
the slit width. The closer the edges of the slits are, the higher the interaction
with the EM wave and the higher the index of refraction and signal mixing that
takes place. The more intense the localized fields, the greater the wave dispersion
and interference mixing that occurs.

http://www.nat.vu.nl/~tvisser/naturephyscomment.pdf

Slit widths vs beam dispersion.
http://hyperphysics.phy-astr.gsu.edu/hbase...c/slitcomps.jpg


Regards,
LL

This post has been edited by Laserlight on Jan 26 2007, 05:29 AM

Hi Good Elf,

Oh dear!

If we have one observation and one assumption and the assumption is incompatible with the observation then what might this be trying to tell us?

I think you've found that any attempt at a pulse response gives the 'wrong answer' in the ripple tank .. this brings us back to the relative value of observations and assumptions. If we change our assumption in the direction of simulating the same steady state response that we observe in reality .. we need to use continuous sinewave excitation.. a possible clue?

I've magnified a bit of the ripple tank image you posted .. so you can see that I'm not cheating.




Despite your best attempts to mess this up there's already enough info present to establish some principles. The 'dark bits' (the destructive interference) are where the waves from the two slits are 180 degrees out of phase .. this is your basic DSE equation in action. If we were at school we'd be asked to measure the length of the blue lines so we know the difference is half a wavelength.
As Visser discovered recently .. if the waves are out of phase at a point (giving a 'zero') then they must be of opposite phases (a red and a yellow) either side of that point.
I have (rather crudely) drawn in the intensity that might be seen at a screen at the bottom of the box, based on the brightness of the wave arriving at that point. Hopefully the how and why and where are reasonably clear from this.

I think that's about the best I can do at present.

Best wishes,

-C2.

This post has been edited by Confused2 on Jan 26 2007, 11:11 AM

And another one..



and a real one



Clearly the spreading algorithm in the ripple tank simulation is a bit enthusiastic .. despite this .. it's pretty fantastic.

-C2.

This post has been edited by Confused2 on Jan 26 2007, 11:01 AM

Hi Confused2,

I will agree that the ripple tank does an amazing job within its parameters. I am not criticizing it just indicating what I think is the biggest failing. I would caution... two wrongs do not make a right. The illumination is not a stationary condition it is a migrating one that provides traveling "uniform" energy distributions over broad zonal "rays" until reflection from a wall. For the purpose of showing that it is initially non-stationary, the illustration with the ripple tank was adequate. It requires "time" to establish those stationary states with ripple tanks. Not so with individual photons... an important point that is overlooked... the main point.

I have already indicated EM Impulse Responses of a system in a previous post and that will do me as a visual aid.
http://forum.physorg.com/index.php?showtop...ndpost&p=167556
I am sure that the relevant work has been done there and shows that impulse responses are fine (both switch on and switch off modes in 1/2 wavelength dipoles). Anyhow I will not push "my barrow" any further.

Cheers

This post has been edited by Good Elf on Jan 26 2007, 03:57 PM

Good Day!
http://www.nat.vu.nl/~tvisser/naturephyscomment.pdf

Regardless of the debate on what paint brush to use the technical improvements are still going on in the labs.
jal

Hi GE, C2, TRoc, Jal and All,

IMO, a bit more theory is required to explain how the EM fields of photons actually
interact with the EM fields of plasmon's. If I understand correctly, current theory
seems to indicate that it is the electrical fields that are interacting, which seems
counter-intuitive somehow. The interaction of electrical and magnetic fields is
well characterized.

If you observe a vertically polararized photon that resembles a normal x,y plane
orientation with y being the magnetic component of the propagating wavefront,
doesn't it seem that the magnetic component of the photon is what is interacting
with the electric component of the plasmon field(s). The enhanced horizontal
spreading of the resulting diffraction pattern on the screen that is seen when
the slit edges are closer together would seem to validate this observation.

If we consider the pattern results observed when "single photon" pulses are
directed thru the slits and still form a periodic distribution, this might be an
explanation that I will toss into the ring for peer evaluation and discussion.
I am thinking that if an electrical field of a plasmon and a magnetic field of
a photon interact at least two things happen, (1) the spin of the photon pulse is
affected and (2) the distribution of the local plasmon EM fields are also changed
or "shifted" from their normal positions via "torque" displacement.

In the case of the photon spin (1) , if it is changed then its normal x,y phase relationship changes so when it interferes with its counterpart, which has been
similarly shifted in its transit thru the other complementary slit, the spins are out
of phase synchronization, and the result of their energy recombination after
passing thru the slits is the interference pattern that is normally recognized.

In the case of the local plasmon fields (2) if the localized EM field distribution is
disrupted, shifted, or offset, subsequent photons will interact differently to the
changed EM fields and the coefficient or degree of spin induced by the
different fields will change the phase timing relationships of the mixing photon
wavefronts according to the plasmon EM field displacements.

This idea also might explain what happens when electrons are used in a DSE
experiment and form a similar interference pattern. The common element is
always the slit geometry and their plasmon fields.

I know that this is thinking way out of the box, but please add your comments,
critique, or alternative perspective to the idea.

Regards,
LL

This post has been edited by Laserlight on Jan 26 2007, 06:29 PM

Good Day Everyone!

Let’s take the following example,

If I used a new paint brush that would allow me to control a mfg process that would keep doubling the distance that the photon travels and as a result I would get a technical monopoly that would represent billions of dollars.
I would be willing to pay millions of dollars to hire the most influential voice to keep proclaiming that the old paint brush (photon waves go to infinity) to keep my secret and monopoly for as long as I could.
This is how capitalism works. Prevent knock offs by any means.
Good elf ….. you’re hired.
jal

Jal,

I don't think that is likely since we are dealing with a structured physical matter
matrix. Atomic displacement or field displacement in the matrix can become
amorphous or randomize its structure to some limited degree, but the EM fields of
the atoms of the slits should "cycle" or reorganize to maintain the balance of the
matrix and the integrity of the "lattice". In effect, over some finite rotational
period, the field and atomic positions will come full circle and the original conditions
should reestablish themselves. IMO, this atomic "cycling" can repeat continuously
as long as external energy fields of a photon "stream" are applied.

If you think about your packing spheres rotating over some extended time
duration, you will see that they will rotate and will cycle thru their rotational period
and come back to their original position at some point in the cycle. The rotational
cycle can continue indefinitely, but the phase angle rotation will always cycle
like a sine wave, back thru its initial zero reference. There are a fixed amount of
contact points (in the packing spheres it is 6, or was it 12?) that is determined by
the orientation of the atoms immediately adjacent to the "center most" affected
atom which is the focal point of the local plasmon EM field.

Other theories, comments, discussion welcomed.
LL

Has there ever been a double slit "double detector" experiment done to see if we can detect the wave bouncing back in the pattern shown in that applet? Just curious! (question posed to anyone who wants to answer)

This post has been edited by "THEY" on Jan 26 2007, 07:06 PM