Falsification of the awareness hypothesis with a quantum eraser adaptation

A quantum information eraser

An simplified adaptation of a quantum eraser experiment by Kim et al. in 1999 is in my opinion very suitable for falsifying the awareness hypothesis. If necessary study the description on Wikipedia carefully to get an idea of its workings.

Setup of the delayed-choice quantum-eraser experiment of Kim et al. Detector D0 is movable

The primary purpose of the adaptation is to be able to verify that the quantum collapse is connected with gained information. Demonstrating the awareness of the observer as necessary for the quantum collapse is a big step from that, however falsifying the consciousness hypothesis is certainly possible with this setup.

Note: conclusions drawn from this 1999 quantum eraser experiment were partly incorrect because the inference pattern seen after erasing the information turned out to be caused by the small differences in the lengths of the traveled light paths to the eraser beam-splitter BSc. However a simplified adaptation of the setup can be used to show the role of information in the quantum collapse.

It’s really about information

In this proposed adaptation, the beam splitter BSc is replaced by two switches behind the D3 and D4 detectors. These switches are operated by a QRNG. The D1 and D2 detectors have been removed. Now the QRNG has become the information eraser. The information about the selected slit, if the switches are in the upper position, is merged into a single signal so that that information is irretrievably lost before it arrives at the coincidence counter. If the measuring instruments entangle quantum wise with the transmitted photons and if the final obtained information is causing the quantum collapse, this is a valid quantum eraser setup. Should ultra fast photonic switches be used, even the delayed choice can be performed, but that is not the issue here.

Adapted quantum Information eraser

The setup with the QRNG driven quantum info eraser – without the trash bin – is intended to investigate whether the quantum wave collapses at the detectors, as is assumed mostly, or that it is about information we have and that the quantum wave does not collapse but just extends itself to the coincidence counter. The “trash bin” indicates the setup needed when we want to falsify the influence of the conscious observer hypothesis.

If we want to determine if there is no need for a conscious observer – which is the falsification of the consciousness hypothesis – we shall simply look at the effect that the erasure of information about the path does with the interference before it can reach the conscious observer. The D3-4 detectors provide information about the selected slit, so that, when conserved, the interference of the signal photons normally disappears. Now we set the switches in the low position so that all D3-4 detections arrive separately at the coincidence counter. Path information is not erased. We do not use now the QRNG info eraser.

Due to the noise sensitivity of the photon detectors, a valid coincidence D0 + D3-4 (R03-04) is the registration of a signal photon in the D0 detector by coincidental registration of an idler photon in D3-4. This setup prevents a noise peak from being registered as a detection. So only a D0 + D3-4 coincidence will be recorded as a valid measurement.

Quantum retro causality and consciousness

Delayed choice experiments show us that even as you postpone the instrumental detection of the chosen path after the signal photon had already reached its destination in the D0 detector contributing to an interference pattern that may or may not appear, you have to suppose that the path detection had to reach back in time in order to effect this. This is what is called quantum retro causality. It means that history is not only revealed by measurement but definitely recorded. It cannot be changed after measurement. This means, something already predicted by John Wheeler, that on the moment you register a photon from a far star on your retina, the full history of the photon including its cosmic path is fixed.

Now consider the idea about the state wave collapse that John von Neumann defended. In his view the quantum state wave only becomes more and more entangled with the measurement apparatus including the physical body of the observer until the awareness of the observer changes the probability into the physical manifestation. If that is what really happens then you don’t have to suppose retro causality. No effect working back into the past. The observer gets only the information about the experiment after both idler and signal have been registered. Important is now to realize that the length of time elapsed between the photon detections and the observer analyzing the results does not matter. Even if the observer waits a month or two before accessing the experimental results the quantum state wave will not end before he observes the results. The end of the quantum state wave seems thus to reach back in time. Compare this with the accountant who registers a change in the books with a timestamp pointing to a financial transaction in the past. That is not retro causality. According to Von Neumann things are not real until they are observed and and only then reveal their past.

Avoiding retro causal effects of the observation

So, if we want to do experiments that confirm the role of the awareness of the observer we have to take this pseudo retro causality effect in account. If we want to falsify the influence of consciousness hypothesis, then absolutely no path information should be recorded. Namely, if ever in the future an observer would decide to view the path information of the recorded coincidences, that would still have a retrospective effect. That would mean that an interference pattern produced by the signal photons does not physically exist all the time and then disappear on retrieving path information. The pattern will just not manifest at the moment the observer looks at the results. To prevent this effect, the path information should therefore be immediately and irrevocably deleted. The only thing that should be recorded is that an R03-04 detection has been done, but not whether it came from D3 or D4. The latter information should disappear directly into the “recycle bin” without the slightest chance of it ever being viewed by a conscious observer. Such an R03-04 registration without information whether it concerned D3 or D4 is referred to as an R0x coincidence. This is a good moment in this exposé to mention the delayed viewing experiments of Helmut Schmidt.


In principle, it is now sufficient to measure with detector D0 at a position where normally full destructive interference occurs. The chance of finding photons there is zero. Should you find photons there, destructive interference is not happening, ergo interference is not happening. Remind, destructive interference is also interference. So we now place the D0 detector on the expected “dead spot”. It should not register anything if the signal photons show interference. However, should interference not occur, detector D0 will record photons at that “dead” spot. Check with yourself if you see why that would be so.

If information on all R0x coincidences in the coincidence counter is irrevocably lost on the path – that is, without the slightest chance that someone could ever see it again – and we still see no interference, then an observing instrument without consciousness, which the coincidence counter is, is apparently sufficient for suppressing interference. In that case the hypothesis that consciousness is needed for the quantum collapse is falsified by the experiment.

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