What If Our Everyday Life Was Quantum Mechanical?

What If our everyday life was based on quantum mechanics? What if macro objects behaved like quantum objects?

If you are in a classroom with 10 chairs, you would appear to a second student, to be sitting on all the seats at once. But as soon as he sits or touches one of the chairs to see if it’s empty, you appear in one of the seats sitting by yourself. And he is then able to take a seat. You were in a superposition, which is the ability of a quantum object such as a photon, electron, atom or anything sufficiently isolated, to be in multiple positions at the same time until it is measured.

This comes from the Schrodinger equation which contains a term called the wave function. The wavefunction for an object contains all the information that describes the quantum object, such as its position, spin, momentum, etc. Objects can take on almost any value according to the wavefunction prior to measurement. The wavefunction only tells us the probability. But once a measurement is made, the properties of the particle gets fixed to only one of the possible states. Note that a measurement is any kind of interaction and is a physical process that does not require a measurer.

Let’s say you hit a squash ball against the wall in front of you. The ball disappears and shows up on the other side. This phenomenon is known as quantum tunneling. In quantum mechanics, when a quantum object like an electron encounters an energy barrier, like a wall, there is a non zero chance that it will end up on the other side of the wall. This is because its wavfunction extends to all of spacetime, meaning it can in principle end up anywhere, including the other side of the wall.

But can any player hit the squash ball in the first place? If the squash ball is a quantum object, it is subject to the Uncertainty Principle. This principle says that there is a fundamental limit to how precisely we can know certain combinations of properties of a particle, such as its position and momentum. So if the player knows where the ball is, he won’t know how fast it’s going. And if he knows how fast it’s going, we won’t know where it is. So taking a swing, he may not hit the ball. This is not due to an observer effect. It’s not a limitation of what we can measure. It is a limitation of what we can know.

If a squash ball machine creates and shoots squash balls onto the wall for practice purposes, you would not actually see any balls coming out of the ball machine. All you would see is balls bouncing off the wall in front of you. What’s happening is that the balls coming out of the ball machine are in superposition. They only become localized and visible after they have interacted with the wall in front of you. Before this happens, their location could be anywhere in the court. The various locations would have a probability associated with them. They could even be outside the court due to quantum tunneling.

Why don’t we actually see this in our everyday experience? Why don’t these quantum behaviors appear in our macro world? Do the laws of quantum mechanics apply only at micro scales? No, the laws of quantum mechanics apply to everything. But the effects of quantum mechanics are too small to be noticed.

Subatomic and atomic scale objects act like waves, and so behave like quantum objects. But large objects are made of a huge number of individual waves, since a squash ball is made of almost 10^15 atoms. All these waves of atoms act in a disorganized and random way. Their individual waves interfere with each other, and average out to zero. This disorganized wave-like behavior is called “decoherence” in physics. And this cumulatively results in classical behavior. In order to get a macro object to behave like a quantum object, we would need all its quadrillions of individual waves to be coherent, and behave like one large wave. This is usually not possible.

But you should know that coherence has been achieved in some large molecules consisting of up to 2000 atoms. Other large scale quantum effects include superconductors, Bose-Einstein condensate and superfluids.