Erwin Schrödinger was born the 12^{th} august in the year of 1887, and he died the 4^{th} january in the year of 1961. Schrödinger was a famous theoretical physicist that was Nobel Prize of physics in 1933, for his famous equation that has his name: Schrödinger’s Equation. This equation, suggested the evolution of a subatomic particle of wavy nature and not relativist.

This equation is more popularly known as “Schrödinger’s cat” the mental experiment that he carried out and which permits to us understand certain aspects of the quantum mechanic.

With this experiment, he tries to explain the quantum’s mechanic functioning, which can be very strange in certain aspects.

The experiment is this one: in the inside of a cage there is a cat, a glass jar which contains a venomous gas inside of it, a mechanism that contains a radioactive particle, and a hammer. During one hour, the radioactive particle has a 50% of possibilities to disintegrate, and the same possibilities of not disintegrating. If it disintegrates, it will run a system that will make fall the hammer, which will break the jar which contains the venomous gas, and the cat will die. If the particle doesn’t disintegrate, it won’t run any system, and all will stay as in the beginning of the experiment, and, therefore, the cat will survive.

After one hour, whether or not the particle has disintegrated, there is the 50% of probabilities that the cat is alive, and the other 50% that he doesn’t. Before opening the cage, we believe that the cat is definitely, or alive, or dead. But, from the point of view of the quantum mechanic, the correct definition, in that moment, of the cat’s wave function (meaning, it’s state), is that the cat is dead and alive at the same time. This phenomenon is called superposition, and it refers, in this case, at the superposition of the states dead and alive. So, from the point of view of the quantum mechanic, each object is in all the possible states at the same time, or take all the decisions at the same time. This can be explained thanks that we know that the electrons can be in two places at the same time, so they can be detected by the two receptors, giving to understand that the cat is dead and alive at the same time. That is to say, that, until we open the cage, the cat is dead and alive at the same time, but, it’s when an observant intervenes, that only one option will remain, having disturbed the wave function, and there will only be one option, which is, dead, or alive.

In a classic display, the cat is or dead or alive before opening the cage, what it happens is that us, we don’t know. However, in the quantum description, the cat is found in a superposition of the states dead and alive, until an observant intervene. When the observant opens the cage, it produces a collapse of the wave function which is irreversible and only one of the two options remains.

Congratulations Ferran, well done. It is not easy to explain the paradox of the interpretation of quantum mechanics. A system stops being a superposition of states and becomes either one or the other when an observation takes place.

Thank you very much for your comment Emili. You’re right with your explanation of the superposition. 😉