Introduction - Elementary Waves

Elementary Waves Move From Detector to Source

The basic Theory of Elementary Waves is quite simple.  The photons that reach your eye as you read this, according to the theory, made it to your eye in these steps:

1. The receptors in your eye are constantly organizing elementary waves which radiate out from your eye at the speed of light
2. Elementary waves from your eye act on the source of the light—an LED, a hot tungsten element, a mercury atom in a fluorescent light—and stimulate the emission of a photon in the opposite direction of the wave back to its source.
3. The photon (always a particle) travels at the speed of light back to the source where it is absorbed and detected as light.

The last step is not surprising because this is how we think of light travelling in the current paradigm. But the first two steps appear very strange and need more explanation.

Model of Elementary Waves emanating from an atom
 in the center. (Created with cloud.sagemath.org)

The first step proposes that elementary waves are travelling out from all matter. At first glance, it appears to say that light actually originates from our eyes and the act of looking makes the light shine. This isn't actually the case. If your eye wasn't organizing the waves and intercepting the light, whatever is behind you would do the same thing and the light would be emitted just the same. It is important to remember that your eye simply organizes the waves, it doesn't create them. They are present at all times throughout the universe, according to the theory.

The second step also needs more explanation. In the current paradigm, photons are emitted from light sources spontaneously without any dependence on their surroundings. In the Theory of Elementary Waves, photons are emitted according to the square of the amplitude of the waves that reach them from the surrounding matter. This idea is not entirely unprecedented in the current paradigm. Stimulated emission is used to explain how lasers work. The additional light from a laser is thought to be stimulated by the photons bouncing back and forth in the laser. The Theory of Elementary Waves provides a cause for so-called spontaneous emission which in the current paradigm does not have a cause.

The idea that all light requires elementary waves to interact with the photon source before light is emitted is a strange idea because we normally think of light being emitted, for instance from a light bulb, spontaneously as soon as we turn on the switch. The Theory of Elementary Waves certainly requires us to look at light emission in a new way. However, we will see that if we accept this strange new idea that photons are only emitted in response to elementary waves from the detector, we can explain some very strange observations. One quick example comes from Young's double slit experiment (more details to come in the Double Slit section of this blog).

In this experiment, if a beam of light is passed through two very small slits (e.g. ten times wider than the wavelength of the light) that are close together (e.g. 0.2 mm), the light will form a complex interference pattern on a screen on the other side.

The details will be explained later, but the important point for now is that if we cover up the right-hand slit and only let light through the left slit, we will get an even distribution of photons as shown in the top figure below (images from opensourcephysics.org. Similarly, if we cover the left-hand slit and leave the right slit open, we will get an almost identical distribution of photons as shown in the bottom figure (the right-hand pattern is moved slightly to the right, but it is too small to see because the distribution of light is much broader than the distance between the slits).

Now if we open up both slits, we see the pattern in the middle of the figure. The interesting part here is that now some portions of the screen don't get any photons hitting it (e.g. in the yellow box), even though photons were detected at that area when either the left or the right slits were open by themselves. A reasonable question at this point is: Where do the photons go when the second slit is opened? If we count the actual number of photons reaching the screen, we find that the part that do receive photons in the middle collect more than when just one slit is open.

If we assume, as in the current paradigm, that the light emitted from the source is constant in all directions and occurs spontaneously (i.e. is not affected by the experimental set up), then something very strange is happening. Photons that traveled through the right slit and landed in the area of the yellow box when only that slit was open now take a different path because the second slit is open. They somehow know that the other slit is now open and decide to take a different path to the one they took when only the one slit was open. Many explanations have been proposed for how this happens and we will explore them in this blog. But keep in mind that they all start with the assumption that light is emitted from a source spontaneously and independent from its surroundings.

The idea that waves travel from the screen to the light source and induce the photons to be emitted is perhaps not so strange anymore. According to the Theory of Elementary Waves, no photons hit the screen in the dark areas of the middle figure because the waves from the atoms in that part of the screen destructively interfere when they reach the light source and thus no photons are emitted in that direction. The areas with increased numbers of photons (compared to the single slit) get more because the waves from those atoms interfere constructively to induce more photons to be emitted from the source.

The Theory of Elementary waves is indeed strange when we first encounter it. However, when we apply it to some of the strange observations involving light, we find that it can explain those strange behaviors quite well.

These three steps: 1) waves are organized by the detector, 2) the waves induce a photon to be emitted, and 3) the photon particle travels back to the detector, are the basic Theory of Elementary Waves. The rest of this blog will see if this simple mechanism can explain some key experiments involving light.

But before we get to the experiments, we should discuss a little bit of philosophy. After each experiment is described, explanations for the results will first be provided according to the Theory of Elementary Waves and then using the current paradigm. In all cases, the preference for which theory seems more plausible or "makes more sense" will be subjective and depend on the background and training of the scientist. Arguments for which theory is "right," or even preferred, cannot be settled without some standard against which to judge them. It is the job of philosophy to set these standards.

Next: How Philosophy can set the standards for proper theories.