This post is a quantum leap

When you talk about a quantum leap to a physicist chances are you are getting strange looks. Why that is and why you are not that wrong will be the topic of this post.

According to the dictionary, a quantum leap describes a sudden, great and important change. For a physicist, only one of these properties holds. So what is a quantum leap, or rather a quantum jump

to use the physical expression?

First things first: What is a quantum? These days, quantum is everywhere. Innovative companies call themselves quantum, whenever there is a hopeless situation in a sci-fi movie, something quantum saves the day, and quantum technology in general has become synonymous with limitless innovative potential. But besides all that, the concept of a quantum is rather simple.

That matter cannot be divided infinitely often is a well-known fact. Atoms are the building bricks of all there is (unfortunately they are not the smallest thing we know, but let’s stick to this analogy). What is not that well known is that other things come in indivisible packages or quanta as well. Energy is one such example. This innocent discovery is the cause of all the quantum theories, technologies, leaps and jumps there are. An energy quantum is called a photon. They are the elementary particles light is made of.

To now understand how light is supposed to jump, we have to go back to atoms. As mentioned before, atoms are not the smallest thing there is. They consist of a core and electrons, that fly around it. The core is positively charged, while the electrons are negative. Therefore, there is some electric energy between them. They attract each other. The closer they are, the higher the attraction. But as we just learned, energy is quantized! This has some unintuitive consequences. If you ever tried to bring two kitchen magnets close together you know how strong the attraction can become and eventually they will stick together. This does not happen in atoms! Because of the quantized energy, only some fixed distances between the core and electrons are allowed and the smallest distance is not zero!

If now a photon hits an electron, for example by shining light at certain metal plates, the electron absorbs it and jumps to the next higher energy level or distance if you like. This is what physicists call a quantum jump. Something suddenly changes by the smallest amount possible.

Comparing this to the definition from the dictionary we see, that a quantum jump is not great and not necessarily of great importance. However, calling a sudden change a quantum leap does acknowledge some aspects of the physical origin.

Next time the news talk about someone achieving a quantum leap just smile and imagine what this sentence would mean: Someone selling one car? Or perhaps changing just one person’s mind? So by using quantum jump the original way, you could make this article a true quantum leap.