Month: December 2024

On ZME Science: Physicists have now visualized the shape of a photon — the smallest unit of light — using a novel theoretical model. These findings offer new insights into how light behaves, potentially paving the way for innovations in nanophotonics and quantum technology.

So, the photon is apparently a ‘thing’ because we can visualize it. But when you read the publication of the phycisists of the Birmingham University a little more careful you will realize that they created a mathematical model, which is not a thing. Their model yields an intensity distribution (or worded differently ‘a probability distribution’) predicting the most probable location where the photon interacts with atoms. As usually happens, the authors of ZME Science confuse a mathematical model with reality, thingness. A very common mistake.

This reminds me of the now obvious mistake of Claudius Ptolemy who, because he wanted to keep the earth in the centre of everything (geocentrism), devised in 150 CE a mathematical model in which the earth (the blue circle in the animation below) was static and the sun and planets moved around it like the attractions in an amusement park. His mathematical model was – despite its wrong basic assumption – an extremely accurate predictor of planet positions, at least as seen from Earth.

Claudius did have an excuse. There were no observations in his time that showed the shortcomings of his model. The telescope had not yet been invented. The authors of the article in ZME Science do not have that mitigating circumstance. They have not realized that the non-material existence of the photon has been demonstrated many times experimentally and that a Nobel Prize has even been awarded for some of those experiments. The photon is not a greenish little thing, it is non-material. And it responds to our observation by adjusting its wave behavior.

Reality doesn’t exist

“Everything is empty in the sense of doesn’t not having an intrinsic reality.” exclaims Carlo Rovelli – quantum gravity physicist – in a YouTube broadcast at 16:04. Quite a statement, especially because everyone has its own – usually not all too clearly defined – idea of what reality is. Which reminds me of a statement we hear so often from Near Death Experiencers: “It was more real than real”. When we believe that everyday material reality is the only reality there is and also that a Near Death Experience is not essentially different from a dream or hallucination, that is, in that light, a remarkable statement.

“More real than real”. Not something I would express after a dream, even though the dream was very real like and impressive. But as soon as you move away from the idea that the daily material world is the only reality, the meaning of Rovelli’s statement also changes. In that light, it is certainly worthwhile to list a number of experiments that, taken together, justify the statement that nothing is having an intrinsic reality. This could shake up your idea of ‘reality’ if you still believe in there-is-only-matter. All these experiments have been described and discussed in great detail in my book, but now it’s a good time, I think, to present them together in a single blog. They confirm each other, without exception.

Einstein’s recoiling slit thought experiment

In the early decades of the 20th century, Einstein was already quite doubtful of the implications of the – at that moment in history – still burgeoning quantum mechanics. He devised a double slit thought experiment with an extra recoiling slit, in which, according to quantum mechanics, and depending on our knowledge of the path taken by the photon, the quantum wave should adapt to this knowledge. That adaptation would have a noticeable effect on the interference pattern produced by the double slit. In his opinion was the idea that our knowledge would influence the quantum wave so utterly absurd that it gave him an argument against quantum mechanics as good sound physics. In his thought experiment he assumed the physical existence of the photon. He had argued its phyical existance himself in his explanation of the photoelectric effect.

The first – confused – ideas in the beginning of the 20^th century about the quantum behaviour of the photon were that it was a real particle of energy, but guided in someway by an immaterial quantum wave. Einstein’s thought experiment was based on that idea. In that way of thinking one could imagine the photon traveling a path. On detection – measurement – the wave would then collapse and start expanding anew from the location where it was discovered. Knowing the path of the photon through the slit means a detection of the short presence of the photon in the slit. From this slit – the place where the photon was measured to be at a certain moment in its path – a totally new single quantum wave would start on its way to the screen. I hope you understand the implications for interference. There is none, a wave has to meet another wave for interference just as you need two hands for clapping.

There is a simpler way to look at this. The quantum wave does not collapse but just reduces itself to one of the slits when our set-up is able to reveal which slit is passed. Why the wave behaves that way in accordance with our knowledge is of course the real question here. Anyhow, when we don’t know which slit was passed, the behaviour of the quantum wave will not reduce to one of the two slits. The result is then two waves, each one going through a slit, meeting and interfering with each other producing interference fringes.

So if there is no way to obtain knowledge about the path of the photon, Einstein said, quantum mechanics predicts that the interference fringes will (re)appear. In the figure below is the same set-up depicted as above but now hermetically closed from inspection by a box, save one small aperture where the photon can leave the box and travel to the screen.

This was a thought experiment to which Bohr actually did not have a good answer, because Bohr then also assumed the physical existence of the photon. Only later did he state in the Copenhagen interpretation that the quantum object does not exist before the measurement, thereby pronouncing the quantum wave to be something not physical.

The real recoiling slit experiment (2014)

Einstein’s thought experiment remained a thought experiment until in 2014 an international team actually succeeded in conducting the recoiling slit experiment in reality. They did it by hitting oxygen molecules with X-ray photons and comparing the quantum physically predicted interference pattern with their result when they could obtain either or not information about which of the two oxygen atoms of the molecule was hit .

Einstein was right, our knowledge of the passed slit (or which atom was hit) influences the interference pattern in a noticable way. So, quantum mechanics is correct in its predictions and Einstein incorrect in denying its implications. The effect is only possible if the photon is an intangible immaterial wave before the measurement (before it hits the detector). The photon therefore does not exist before detection. See the experimental result below.

Conclusions: the immaterial quantum wave is reduced by our knowledge and the photon does not exist on its way to the screen. We are intrinsically connected the the world we observe.

The first delayed choice Maryland experiment (1982)

In 1982, a specially designed double slit experiment was conducted at the University of Maryland to expose what happens when we irrevocably destroy the knowledge of the chosen path of the photon after the photon should have passed the double slit already. Unfortunately the experimental set-up was somewhat flawed, it had a design error and the final result cannot be used as evidence for the materialization of the foton on measurement. Despite this flaw, the outcome confirmed Einstein’s insight. When we have knowledge of the passed slit, the interference fringes are not shown. We only see a spread-out spot fading out to the edges.

Conclusion: Photons travel all te way to the detector as a non-material wave, not as real things. These waves respond to our knowledge of the path traveled.

Delayed quantum eraser experiment with slow moving atoms

Because also atoms show wave behaviour according to quantum physics, interference effects can also be demonstrated using atoms. Because they do not move at the speed of light like photons, there is better opportunity to irrevocably destroy the knowledge about the path that it followed before the atom reaches the detector. In 2015, Australian physicists managed to conduct a so-called Mach-Zehnder delayed choice experiment with slow-moving helium atoms. The result confirmed that as soon as we have knowledge of the path that is traveled, the interference (red line in the figure below) disappears (blue horizontal line).

For a more detailed description of this experiment, see elsewhere on this site.

Conclusion: before detection the atom exists as an immaterial wave, not as a thing.

The second and correct delayed choice Maryland experiment (2007)

In Maryland, a retake of the flawed delayed choice experiment from 1982 was conducted in 2007 with more up-to-date techniques, apparently this time succesfull. They used entangled photon pairs for which one of such an entangled pair – the idler – carried the information about the other’s path – the signal. The irrevocable destruction of that information by the idler had indeed – now experimentally soundly demonstrated – the effect that the interference pattern of the signal photon disappeared. Even after it had already passed the double slit. Clearly a confirmation of wave behavior up to the time of the physical measurement.

So here also no material photons before the measurement by the detectors. Watch the timeline of both situations – either erasure or preservation of path information – very carefully.

You can see from the picture above that the so-called retrocausality – an effect that would change the past – is very probably an effect caused by the experience of the observer observing the results of the experiment. It is not only matter that doesn’t exist before observation, it’s also history that exists from the moment of observation on, not before. For a more detailed description of this experiment, see elsewhere on this site.

Thirteen Bell-type experiments (1972 – 2016)

The Bell-type experiments are too complex to explain here briefly. In short, the entanglement of photons, which says that the physical properties they showed on measurement would be instanteneously correlated, was investigated. But despite a lot of criticism from the scientific community on these experiments, or perhaps because of that criticism, the experiments were carried out better and ever less and less rebuttable over the years. So, it has been confirmed now with considerable certainty that the photons

• did not exist materially before detection and showed their correlated properties at the moment of detection, or
• that they did exist materially and were in contact with each other through spooky faster-than-light communication in order to correlate their properties.

In the Delft experiment in 2016, all possibilities for unintended influence of the entangled photons (loopholes) were ultimately excluded, as a result of which the result should be accepted worldwide. Choose for yourself which of the two possibilities is the most likely. Be aware anyhow that a Nobel Prize is awarded to three of the experimenting physicists “for experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science”.

Photons are definitely not material things

So, too bad for the editors of ZME Science. No hurray for the thing-like properties of the photon. Incidentally, the scientists at the University of Birmingham did not make it a secret that their model is intended to make mathematical predictions about the reactions of light to matter to atomic scale. So, a typical case of reification of an abstract mathematical model by phycisists and by popular science media. Which happens regularly. There is an increasing number of – mostly young – physicists who are aware of that.

Unfortunately for those who do not like to give up their idea of a there-is-only-matter world. But perhaps good news for the more spiritual-thinking minds who have seen that matter, space and time are only an illusion. Incidentally, I would like to point out that an illusion does not have to be inferior to the so-called concrete reality. An illusion is not something that would render the world we experience less valuable. On the contrary. The possibilities and opportunities for ‘real’ and valuable experiences in an ‘illusional’ environment are vastly more impressive.