Quantum mechanics means that happiness exists

What is coincidence?

One speaks of chance when an event is unpredictable, when it is not deterministic. Natural science was originally pursued in order to suppress chance. But today we know that chance is an indispensable and fundamental part of nature.

What is coincidence?

"God does not play dice"Albert Einstein once said.

For a long time, terms like fate or luck had no place in science. But at the latest since the introduction of quantum physics, scientists can no longer ignore the factor “chance”.

He's actually directing the microcosm. In the world of atoms, individual events are basically no longer precisely predictable (no longer deterministic).

They only occur with a certain, but at least with a calculable probability.


The subjective coincidence:

For example, if we take a dice in hand, the sequence of numbers obtained will be purely random if we roll the dice "fairly". We get the "1" on average the same number of times as the "6" and do not know in advance what the next number will be. But we can imagine that in principle there would be an exact explanation for every single throw, if we only knew all the details exactly enough. So if we knew how the hand moves when throwing, how great the air resistance is for the cube or what the surface of the table is exactly like.

In practice, however, such a prediction is not really successful, since we generally do not know all the parameters that influence the experiment precisely enough. One speaks here of a subjective coincidence, since it is only subjectively unknown what exactly is going on. Objectively speaking, however, there is a reason for the result of every throw, even if we do not know or recognize it.


The objective coincidence:

It looks different in quantum physics. Quantum physics has triggered a renewed discussion about whether the world obeys fundamentally deterministic (i.e. predictable) or innermost random principles. The experimentally proven violation of Bell's inequality * implies that nature on the microscopic level is not described by a realistic and local theory.

This means that the result of an experiment cannot generally be predicted exactly, even if all local conditions are known, and accordingly different consequences can follow from identical initial situations.

A good example of real chance in physics is radioactive decay. For example, imagine a single radioactive atom. We know about this atom that it will eventually decay, and we can state the probability that it will decay within the next ten minutes, for example. However, the concrete decay will occur at a certain point in time, and we have no way of predicting that decay. Quantum physics says that there is no reason whatsoever, not even a hidden one, for the point in time of the individual decay. One speaks here of an objective coincidence.

The coincidence does not arise because properties of the nucleus are still unknown, but because there is no objective reason. So there are no (local) causes.

This objective coincidence is probably one of the most profound discoveries in science of our century.

However, quantum mechanical coincidence must not be equated with irregularity. Even if the individual measurement results cannot be predicted, the probabilities of their occurrence are strictly determined by the laws of quantum mechanics.


* Bell's inequality describes the probability of measurements of entangled states and assumes that the states are already determined by "hidden parameters". Then there are also certain values ​​for the inequality, which, depending on the structure of the apparatus, can also be expressed in numbers. Quantum mechanics now violates this inequality (also experimentally). That means that you have to give up either the locality or the realism. In any case, it means that there are no hidden parameters.


Here is a nice video about "coincidence"







(Compiled by Barbara Buchmann)
Photo: Tim Goudw, Unsplash