The widespread message about the universe that we live in, is that it is almost empty, cold and indifferent and that life is only accidental, brutish and hard. I have a completely different opinion thanks inter alia to quantum physics. The universe is by no means indifferent to us, on the contrary. A study of the behavior of the quantum field, that the universe actually is, shows us that it responds very carefully to what we think, know and expect. In its manifestations, the quantum field even takes into account our possible future actions plus the contents of our consciousness. These conclusions can be drawn from the results of certain experiments that can even be understood by the non-physicist, if in possession of an open mind and willing to think a little bit harder than usual.
The quantum field – as recognized by the most physicists at the moment – is a non-local ubiquitous, not directly measurable, and intangible field from which all matter and energy manifests itself on measurement. Replace right away the word measurement here with observation. Many physicists are already doing that. Accepting that, the observer gets an important participating role in this manifestation of matter and energy. In other words, the quantum field is the invisible source from which everything we experience arises, which is by the way very reminiscent of the TAO. Many have already noticed that agreement.
Until the middle of the last century, a field in the physicists sense of the word was a state of space through which objects that are sensitive to that field, experience forces depending on their position in that field. A field, in that sense, is the way physicists try to deal with forces at a distance that are exerted through empty space. Examples are the gravitational field, the electromagnetic field, the Higgs field. A field is therefore essentially non-material. The nature of those field forces is still a mystery, although we can calculate and predict their effects. The quantum field is even another step less physical, it does not exert forces but is the source from which the matter and energy appears – and disappears into it. Most likely, the quantum field is also the source of space and time itself, but I will not go into that now.
The observer matters, literally
The properties of the quantum field can be described mathematically despite that intangible capacity. The Schrödinger equation is a good example of this. The Schrödinger equation solution describes a complex wave. Complex means that the described values cannot be expressed in easily imaginable numbers. Imaginary values, numbers whose square is negative – something that does not fit within our frame of mind – play an essential role. Fortunately, those imaginary values dissappear if we want to use the wave function as a an amazing efficient predictor of the probability of finding an object in our measurements. It is important here to remember that this wave does not describe the effect of the observation, the measurement. Without observation, the immaterial wave of possibilities would continue forever. The observer plays an essential role in the matter and energy emerging from the quantum field.
The effect of the observation is that the infinite collection of possibilities, which moves through the quantum field as a wave, results in a concrete experience, the so-called quantum collapse. I think that collapse is actually an unfortunate term. The term quantum collapse suggests a breakdown of something material where only one element remains. However, the quantum field is not material, not even a small bit. A term that better expresses what is happening is the ‘reduction of the quantum wave‘. The quantum wave can be reduced by our information to a smaller wave containing fewer possibilities. The final reduction is then to that of a single possibility, which is then 100% probable and is therefore the observed manifestation. That’s the bright spot on the screen when a photon hits, for example. The picture evoked by the term ‘reduction of the quantum wave’ helps us a lot better in our attempts at understanding.
Delayed choice quantum eraser and conscious observation
This ultimate reduction as a result of observation is called the observer effect in quantum physics, something that is still hotly discussed. The big question is whether it is the physical measurement, or whether it is the observer and his consciousness, which produces the effect, the reduction (or collapse) nof the quantum wave. That is a subtle problem for which no experiment seems to be configurable to answer this. Measurements without observation seem obviously worthless. As long as we are not allowed to observe the result, we cannot use the outcome, of course. A clear catch-22 situation. But there is an important experiment that seems to come very close to measuring without direct observation. I would like to describe this experiment here in such a way that its consequences will become clear and understandable.
That is the two-slit quantum eraser experiment with delayed choice. The delayed choice concerns the effect of whether or not to irrevocably erase measurement information before it has arrived in an observer’s consciousness or is registered – on the computer hard disk for example – so that conscious observation is still possible, albeit at a later moment.
The quantum eraser experiment is a two-slit experiment that is designed in such a way that we can detect and register the slit through which the wave went. The effect of this erasure is that the quantum wave then ‘magically’ reduces to one of the two slits. We can then see, because there exists now only a single wave between the slits and the screen, that the wave will no longer interfere with itself. We then no longer see the typical double-slit interference pattern of dark and light bands, the result is a single spread-out spot. Einstein already realized in around 1920 that mere observation of the slit would evoke this strange quantum effect and devised a notorious thought experiment with which he hoped to falsify quantum mechanics. His thought experiment was much later technically realized and the disappearance of the interference pattern on observation has been confirmed. Einstein thus played the role of devil’s advocate in his brilliant way, thereby contributing much to quantum physics.
The law of conservation of information
We can see this quantum behavior as the result of information in motion. The more information we receive, the more the information in the quantum wave will be reduced. This is because that information reduces the – infinite – number of possibilities in the quantum wave by moving that information to a location accessible to our consciousness. The more we know, the fewer probabilities there will be to realize. That is an effect that we can experience daily, such as in using a public transportation planner to avoid surprises with our planned trips. The more information, the fewer surprises. We can therefore also consider the quantum field as a universal information field. Physicists have thus discovered a new conservation law relevant to that quantum field, the law of conservation of information. When we can capture more information about the measured object, that means that the information in the quantum field moves to a location accessible to us, but always still within that field. The wave of possibilities is thereby reduced. The information is of course still within the quantum field, but now in a location where we have access to.
Let’s now visualize this in some diagrams. It may then become easier to understand what happens in a quantum eraser experiment. We will first look therefore at the basic implementation of a double-slit experiment. A single wave arrives at the two slits at the same time. The two slits then become sources of synchronous – simultaneously moving – waves. Those waves meet after the slits again and reinforce or extinguish each other in certain locations. These locations of reinforced motion form then contiguous curved lines. This creates – with light waves – the familiar interference pattern of dark and light fringes. With sound waves of a single tone (monochromatic sound) you will get areas of loudness and silence. You can do a double-slit experiment with sound at home with two simple speakers and a tone generator. With a distance between the speakers of 50 cm and a frequency of 800 Hz, the effect is easy to hear.
Quantum information collections pictured in Venn diagrams
We can use a Venn diagram to show how the information of an experiment gets distributed in the quantum field. The Venn diagrams then represent collections of quantum information. The ubiquitous quantum information field is then the set that contains all information in the universe, and all other collections are subsets of it. In anticipation of what will be argued further, I distinguish between:
- The set of information provided by the experiment (green).
- The set of information that the experiment yields and that has already been observed and incorporated into consciousness (yellow).
The yellow set is therefore a subset of the green one. For example, the information in the green set that is not in the yellow one may contain information that is already stored on a hard disk but has not yet been observed by anyone. When observing the contents of the hard disk, that information moves from somewhere in the green set to the yellow set of observed and in consciousness stored information. Because we are ultimately also collections of information, you could also consider the yellow set as representative of ourselves, the observers of the universe.
When we now organize the experiment in such a way that we can determine the slit through which the quantum wave travels, we will get the picture below. Now try to understand the following well. Remember that the quantum wave represents the sum of all probabilities of finding the object upon observation. If we can know which slit the wave is passing, that’s the slit where the sum of all probabilities is 100 %. Then it is undeniably clear that the wave travels through only one slit. I hope you understand that. For the other slit, there is no chance, no possibility, left for the object to manifest there. An observation that is usually interpreted – and unnecessarily – as that the object existed actually in one of the slits. That interpretation is the result of the confusing dual wave-particle image that is so often presented in the media about quantum physics.
Just as an aside. In the usual descriptions of the double-slit experiment, there is usually talk of an object – a photon, an electron, a molecule, a virus – that passes through the slit. As if that object appeared temporarily in the slit and then happily continued as a wave again. You will also find this description in my first book. Frankly, that's an unprovable and unnecessary assumption. It is never the case that the object is observed going through the slit in its passage. The image of a wave that is reduced to one slit is a lot simpler and therefore, in my opinion, better. It explains the disappearance of the interference pattern just as well, with fewer assumptions and is therefore preferred.
In a Korean experiment, the effect of information on the quantum wave has been beautifully demonstrated. The more information we have about one of the paths the wave can go, the stronger the wave on the other path is reduced. This relationship can be described by a simple algebraic formula that is very similar to the Pythagorean formula for the sides of a right triangle: a2 + b2 = c2. The left leg of the mannikin then represents the information we have about one path and the right leg represents the probablity to find the particle on the other. In the extreme positions (of the legs) the path information is maximal and the probability to find the particle on the path corresponding to the other leg is reduced to zero. Or the other way around.
The Venn diagram below shows that the information in the quantum information field, which relates to the object, moves to the green set when measured, which is the information we obtained from the experiment. So no information is added in the quantum field of the universe, it only moves to another location and has therefore an effect on the observed world. The interference pattern disappears. The result is now a spread-out spot.
The erasure of information has consequences for what we observe
In the previous diagram I placed the information about the object in the green set – ‘The information from the experiment’ – but not in the ‘Consciously perceived information’. This relocation of information, despite the fact that we have not yet consciously processed it, has the experimentally demonstrated effect of the disappearance of the interference fringes. But if this information has not yet entered an observing consciousness – the yellow set – then it is still possible to radically erase this information with the result that it can no longer end up in our consciousness.
The observable effect of erasing that not yet observed information is – surprisingly – the return of the interference pattern. This is the quantum eraser experiment in which – for example via semi-permeable mirrors – the information is randomly and unpredictably erased or not, before it can be registered. So, erasing is actually moving information to a location that is no longer accessible by us in the quantum field.
The conclusion that can be drawn from the return of the interference pattern is astonishing as far as I am concerned. It means that the quantum wave even responds to information that is not yet in our consciousness but could end up there in the future. This also means that the quantum wave changes retroactively since the erasure is always in time after the passage through the slits. That’s why it’s called delayed.
Would you have become curious about the technical details of all mentioned experiments, especially the delayed choice ones, they are described in detail in my book 'Quantum Physics is NOT Weird' available at Amazon in the US and also at BookMundo in the UK.
Future-proof behavior
The quantum field therefore also takes our possible future actions and content of consciousness into account. It cannot and should not be the case that the interference does not disappear and that therefore the wave must have went through both slits, but that then at some point in the future we observed the result that was waiting for us on the hard disk, and that we then have to conclude that we then know which slit the wave passed and consequently not the other one. Which irrevocably impossible means that we should not have observed interference in the experiment, while we remember we did. Perhaps we published it already. A severe violation of our remembered history or of the laws of nature that would radically overturn everything we assumed as real. Luckily, the recorded completed past is irrevocable. Nice indeed.
Tat Vam Asi
The astonishing conclusion is therefore that the reduction of the quantum wave to a single slit, which destroys the interference pattern, is not the direct result of the physical measurement, but depends on the possibility whether that result can be observed now or in the future. The quantum field is therefore very strongly connected to our consciousness and its future. Perhaps the field and our (greater) consciousness are identical, which aptly corresponds to the Tat Vam Asi (You Are the Absolute) of the Upanishads.
In any case, for me this means a mind-bogglingly intelligent and careful universe that is constantly making adjustments in its quantum field, so that we, conscious beings, have the experience of a universe that usually conforms to the laws we have established and therefore behaves in a predictable way for us. Very accommodating that. The quantum field therefore behaves like the intelligent director of a mind-bogglingly rich and complex play with an unimaginably careful attention to everything that takes place on the stage. Call it love.
In the fury of the moment I can see the Master's hand
In every leaf that trembles, in every grain of sand.
Bob Dylan
Paul J. van Leeuwen graduated in applied physics in Delft TU in 1974. There was little attention to the significance of quantum physics for the view on reality at that time. However, much later in his life he discovered that there is an important and clear connection between quantum physics and consciousness.