- Quantum systems cannot be described using ordinary numbers.
- Eigenstate is the state in which we can describe quantum systems using ordinary numbers.
- Electrons appear on a screen when going through a double-slit, meaning they exist, even if they are quantum particles.
No matter how much the human species evolves, and no matter how much we learn and find out every day, it is undeniable that we will always have questions about the universe. While we may believe that we discovered all there is to know about our planet, the vast infinity of space seems like it will forever hold a large number of mysteries. This is something we all agree upon.
However, sometimes, you may have heard someone ask if the universe exists if we are not observing it, and wondered how does one come up with such a question? The universe is around us; of course, it exists. This question stems from the attempts of trying to understand modern physics from populist articles or theories. But the answer is yes, the universe exists if we are not observing it.
People can be heard saying that quantum physics claims that matter does not exist when no one is there to notice it. This begs the question, would the universe cease to be, if no life was in it? However, statements like these usually come from people that fail to understand quantum physics properly.
A quantum system does not exist in states similar to those of the world that we know. We cannot describe it using ordinary means, but in regards to physics, it is better to say that it cannot be described using numbers. Standard objects, on the other hand, can be described using numbers. We can express their velocity, position, and all other physical features using numerical values.
It should be noted that a normal or classical object is also made up of quantum particles. When we say ''normal object'', we mean basically everything; be it a person, a dog, a car, or an entire planet. Everything is made of an extensive amount of quantum particles. This fact means that all objects are systems, however, in these systems, we can balance the quantum behavior, and we are able to use numbers to describe them, as we would with a regular or classical object.
Occasionally, we may run into certain parts or qualities of quantum systems that we can describe using ordinary numbers. Quantum systems achieve such states only briefly, and we call that state the “eigenstate.” “Eigen” is the German word that means “own.” Using this terminology, we refer to the numerical value used to describe this state as the “eigenvalue.” Quantum systems achieve their eigenstate when they interact with classical systems. Most often, this means that we are trying to measure something.
This is best described through experiments involving the observation of electrons. To keep it as simple as possible, those experiments aim to get the electrons to appear on a screen, which would prove that they can display characteristics of classical waves and particles.
However, while getting to the screen, the electrons are invisible to us, it does not have a normal position, and it behaves in ways that no classical object can. But that does not mean the electron does not exist! We just cannot describe it with ordinary numbers. Even if our observations affect the universe, it would still exist without us.