Quantum Observer
Setting straight some deceptions of quantum mysticism
When it comes to quantum mechanics, sometimes I feel as if the overall situation could be summed up as, “Yes, we all can observe the same effects, but none of us has a clue what we are actually looking at.” However, when one delves a bit deeper than the superficial popular speculations and sees some of the actual experiments, a lot of wild misconceptions really do evaporate. In my quest to elucidate myself on the topic, I came across several interesting facts and made a few observations that I want to share with you now.
Let’s start with the iconic double-slit experiment.
If you ever stepped into the dangerous waters of QM, there is no way you could miss it. In case you don’t know what I’m talking about, but even if you do, please watch the following video that not only explains the whole deal in great detail but actually demonstrates it in the most precise way I saw to date.
I hope you enjoyed the video as much as I did, so let’s move to the heart of the matter that is the quantum observer.
As far as I get it, depending on a particular interpretation of QM an observer is either essential, inconsequential, or undefined. Well, talk about exact science. Anyway, although some interpretations go as far as to require a sentient observer, the actual nature of observation can be reduced to a specific kind of interaction (such as measurement) that causes the particle-wave to lose its coherence (the famous collapse of wave function) and become entangled with the measuring apparatus.
This interaction, however, does not have to measure anything at all. It’s enough to alter some properties of the particle as can be demonstrated with e.g. double-slit quantum eraser experiment. There are a lot of wild claims about implications of this experiment, but before I go any further, please watch the following video of the experiment in action.
You have probably noticed that instead of two distinct, projected slits as is the usual description of the effect of measurement (or observation) at the slit, the actual result is just the lack of interference pattern. Rest assured, that is not a fault of the DIY setting you saw, but the expected result (unless I missed something substantial :D). Basically, what you witnessed was a removal and restoration of “what slit” information of a particle. For a more in-depth explanation, please watch the following video.
Now, you may argue that other QM interpretations may explain these results in a wildly different way and you would be probably correct. There are, however, two additional details that I’d like to mention.
First, entropy was proved to be reversible, which probably just further proves the next point (but I must admit that in this particular case I’m merely intuitively guessing how it ties to the “big picture”).
Second, quantum no-hiding theorem was experimentally confirmed. If you ask what the heck is that and what it means — in short, it’s a fundamental consequence of the linearity and unitarity of QM as follows from Schrödinger’s equation (i.e. before decoherence / entaglement the time evolution of wave function is deterministic). That means that information can never be lost, only transformed and past and future quantum states can be determined. Well, to be honest this is a bit more complex, but I would dare to (wildly) speculate that it strongly suggests that quantum information interpretation of QM may be a viable path. Not exactly as immaterialism or neo-idealism (holographic principle is an interesting concept worth to explore for many different reasons though), but more in line with “physical” computing systems.
Thus, don’t expect me to end this piece with some definitive theory. Frankly, I have more questions than answers in this case, but one thing became crystal clear to me — quantum mysticism as it is presented by its proponents is a verifiable bullshit. After all, if human consciousness or mind were essential to QM in the way they propose, I would never be able to observe all those mind-boggling experiments.
