University of Helsinki
We all feel blue every now and then. Sometimes it feels like everything is out control, as if our actions, or lack of such, does not really make that big of a difference. If we are not capable of affecting our own life, we surely cannot influence physical phenomena, right? Actually, what if I told you that just by observing we are able to affect reality… in the quantum world!
A study conducted by researchers of Weizmann Institute of Science demonstrated that the distribution of electrons passing through the double slit was affected by the act of having been observed. The most remarkable outcome of the study is that it was proven: “the greater the amount of “watching”, the greater the observer’s influence on what actually takes place”.
Let us have a glance at how it all began. Up untl the beginning of the 20th century, our world would be explained by the so-called realist theories, which included classical mechanics, statistical mechanic, special and general relativity. The basis of these realist theories is that we are able to observe physical phenomena, and our observations do not have an impact on the results of the observation. It is this assumption that makes the theories realist, i.e. allows to predict any phenomenon either exactly or probabilistically, using chaos theory of classical statistical mechanics. It all changed when quantum physics came to be. Quantum physics is well described by N. Bohr, who stated that each observation in quantum physics becomes a singular, each time unique act of creation of quantum phenomenon, rather than a mere observation of the pre-existing property of a quantum object.
Now that we have gotten a sufficient insight, let us see how the experiment by Weizmann Institute of Science proceded in 1998.The experiment was designed the following way. Researchers used a very very small measuring device (less than a micron in size), which could spot passing electrons. Its precision was calibrated by varying the current passing through the device. The device was then set to detect the electrons passing through the openings. The electrons seemed to be passing through the slits like particles, and no interference patters was then observed. After that, the device has been switched off, and the electrons exhibited wave-like behaviour, showing interference pattern, i.e. passing through two slits at the same time. To researchers` surprise, when the detector was plugged in again, but with smaller precision (it could no longer detect every electron passing through the slits), the beam of electrons was still producing interference patters, but this interference would get weaker the more precise the detector was set to be.
What does this all mean and how would it affect us, ordinary popular science blog readers? In fact, such unique properties of the quantum world are likely to be widely used in many spheres. One of the more promising scenarios is using quantum effect described above to ensure the safety of information transfer. This can be achieved by decoding information in a way that would require the interference of electron paths to decipher it. This way, the interference will not occur if it is being observed by someone, that is, the secrecy of information tranfer is being compromised.
Artem Mkrtychyan
Citations:
ScienceDaily. (1998, February 27). Quantum theory demonstrated: Observation affects reality. ScienceDaily. https://www.sciencedaily.com/releases/1998/02/980227055013.htm
Plotnitsky A. 2023 ‘Theagency of observation not to be neglected’:complementarity, causality and the arrow ofevents in quantum and quantum-like theories.Phil.Trans.R.Soc.A381: 20220295.https://doi.org/10.1098/rsta.2022.0295