Finished, the good resolutions that we do not respect ! That this is weight loss, smoking cessation or the practice of a sport, these resolutions, a priori, wise remain, however, difficult to hold. It is clear that this list is robbed of a certain originality in repeating every year. It is time to take a resolution that one is able to honour without cowardice or laziness. A resolution a priori ambitious, which will surprise your entourage : the taming of the Schrödinger cat ! The good resolution of 2019 will be quantum or will not be !

While many of us have heard the story Schrodinger’s cat dead and alive at the same time, we are in fact a minority to understand the meaning of quantum. In 1935, the physicist Erwin Schrödinger proposed an experiment fully imagined in which a cat is enclosed in an opaque box that contains a mechanical device, which triggers the release of a deadly poison if the radioactive element to which it is attached is disintegrating. Discard the radioactive element of the story which is simply there to emphasize the randomness of the death of the cat. The only way to check the state of the cat (dead or alive) is to open the box. As long as the box is closed, the cat has a chance of being death and one chance in two of being alive. This experience symbolizes two paradoxes in quantum physics that are the superposition principle and the measurement problem.

the measurement Problem

The area is represented at the atomic scale by networks of atoms that are each represented by, among others, a nucleus and a cloud of electrons that surrounds it. The principle of quantum superposition allows an element the atomic as the electron to exist in different physical states. In the thought experiment of Schrödinger, the cat represents the element’s atomic, and the terms dead and alive are its physical states at the same time. To explain it simply, let us take the case of the hydrogen atom which contains only one electron moving around its nucleus. The scale of the atom, the time scales are so small that quantum physics becomes probabilistic. Written differently, the electron is so fast that it is localized according to a certain probability, all the possible positions around the nucleus hydrogen : the electron is both here and there, or down there, which provide him with possibly different levels of energy simultaneously. The experience of the Schrödinger cat also highlights the problem of measurement, which presupposes a disturbance of the result by the measurement itself. In other words, how to ensure that this is not the opening of the box (the extent) that kills the cat (the result) ? In the case of the hydrogen atom, measure in practice the position of the electron around the nucleus would disrupt the result by capturing a particular position. Another measure would provide a different position in the field of the possible positions of the electron.

The measurement problem and the superposition principle of quantum fuel without complex discussions of your eve dinner under the astonished gaze of your guests pleasantly surprised. A nice resolution to master each year a scientific principle ! A small resolution for Man, one giant leap for our civilization ! See you next year !


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