Category Archives: figures

Quantum Weirdness – A Matter of Relativity? Part 2

Quantum Weirdness

A Matter of Relativity? 


Copyright 2006/2007 James A. Tabb 

Part 2 – Double Slit Weirdness

When a proper light source (coherent – light from a single source all at the same frequency) is placed in front of a screen with a narrow slit, the light is diffracted (spread out) as it goes through the slit and appears as a shaded band centered on a screen or photographic film. The light is scattered and/or bent by the edges of the slit as shown in Figure 3.

Single Slit Diffraction
Figure 3. Single Slit Diffraction

 If we add two more slits located side by side between the first slit and the screen, the light passing through each of the new slits is diffracted again such that the photons from each slit are bent across each path and combine to reinforce or cancel each other where they strike the screen.

 Double Slit Diffraction

Figure 4. Double Slit Interference

The result is an interference pattern (light and dark bands) on the screen as shown in Figure 4. If you block either of the two middle slits, the interference pattern disappears. If a photographic film replaces the screen and the intensity is reduced so that only a few hundred photons are sent through the double slits before the film is developed, the interference pattern will be made up of individual dots organized in a pattern that duplicates the interference pattern. Keep the film in place long enough and the patterns become more complete. Put a cover over one of the slits and the film still shows dots, but no interference pattern, only a diffraction band. Put a detector in one of the slits and the interference pattern also disappears.

Now if the light source is reduced in intensity enough to send only one photon at a time, a weird result can be seen if the photographic film is left long enough (days or even months in a very dark box) where both slits are left open. The interference pattern continues to develop on the film, even though there is no possibility of interference (or even photon bumping) unless the individual photons go through both slits somehow.

Part of the current explanation is that the photon goes both ways, but any measurement (putting a detector in the path) always disturbs the measurement. In fact a whole class of quantum theory has developed around the inability to make precise measurements due to the measurement disturbance problem. How do we explain this quantum weirdness?

A Matter of Relativity

There are two processes going here. One process is the real time that our experimenter sees, about 1 nanosecond per foot of photon travel. The photon is traveling through the experiment with real and measurable delays from the emitter to the first slit and from there to the double slits and from there to the film. The other process is that the photon’s relativistic path is zero so it is in contact with the film and the emitter at once and all of its paths in between are of zero length and require zero time. All paths that can lead to the same path are conjoined. Time of flight and distances for the photon expand only as it passes through the setup. The photon and the observer see simultaneous events differently. All the events are simultaneous to the photon, but none are to the experimenter.

All the elements of our experiment have no depth and seem to be congruent as if they were paper cutouts that have been bonded together with the emitting source. As observers, we can’t see it. As the photon leaves one element of our experiment, such as the first screen with one slit, the double slits are squeezed down to a point and plastered across its nose. The photon easily fits across both slits of the second screen as the distances to them are zero and thus the distance between them is also zero. Indeed it fits across the entire second screen, but the edges are less distorted. Since the photon is also plastered across the slits, everything behind the slits is also plastered there – the entire path is available at one instant as in Figure 5 a. The photon is able to take all paths (even simultaneously) that lead to a common point because they are all in front of it as it enters our experiment, and zero distance separates all the paths. No amount of fiddling with flipping mirrors or detectors will fool the photon into disclosing its path because the mirrors and detectors are also plastered to the photon’s nose throughout its (instantaneous) flight. The mirrors and detectors are in place when the photon makes its decision or they are not. The result is path shut or open.

As the photon moves from the first screen to the second, the second screen moves with it (attached to its nose) until it reaches its normal (real world as we see it) dimension and then expands as the photon moves into the slits as in Figure 5 b. Portions perpendicular to the path of the photon become normal size and atoms from the edges again buffet the photon.  Everything behind the photon is of no consequence, gone – vanished.

Relativistic Double Slit

Figure 5. – Relativistic Double Slit

 From the relativistic point of view, the photon has a number of crisis points such as within the first slit. As it passes through the first slit, the atoms at the edge of the slit buffet it and the photon’s path is randomly diffracted from the original path.   The slit has grown to normal size (perpendicular to the photon’s travel) but now the photon is virtually attached to the entire screen containing the double slits in the background that represent the next crisis point or wakeup call. If neither slit is blocked, it has an opportunity to go through both.

Photon Recombining

Figure 6. Photon Recombining

I see the photon as being a packet of energy that obeys the laws of conservation of energy. It flows around the barrier between the two slits only if it can recombine on the other side without ever completely breaking into two separate pieces. It behaves almost like a perfect fluid and leaks through where it can, but unlike a perfect fluid, it cannot separate into multiple “drops”.

If the packet can meld behind the slit spacer as in figure 6, it does so before it separates in front of the spacer. The melding process takes place an integral number of wavelengths from the slits and results in a change in path that leads to an impact in the interference pattern, a pattern that can be calculated using the methods of QED.  As soon as the melding takes place, the photon separates in front of the slit spacer and begins joining the rest of the body already melded together, so that the photon is always a full packet of energy

If melding does not take place because of a blocking detector or some other shield, then the photon pulls itself into whichever slit passed the bigger portion of its packet and slips through that slit whole.  If it is the blocked slit, it is destroyed there.  If it is the unblocked slit, it comes though whole but does not interfere with itself because it did not meld around the slit due to the blockage in the other slit.  It may also be destroyed by the slit itself.   The photon is destroyed in the blocked slit or on the film behind the open one, never both. It makes no choice. In the case of a blocked slit, there is no recombination. The side with the larger energy pulls the photon through an opening if there is one and if that opening has a detector or blockage, it dies there.

The answer to the weirdness of photons seeming to interefere with itself is that it is due to the forshortening of the experiment due to the effects of relativity.

Next:  Polarized Light Weirdness Explained