Quantum Physics for Dummies

Imagine this: In a steel box is a cat, as well as a poison with a 50% chance to kill the cat within the hour. One hour later, without opening the box, you must tell whether the cat is alive or dead. The correct answer is… both.

This experiment is a simplified version of the Thought experiment of Shrӧdinger’s Cat, and a good introduction of one of the first fundamentals of quantum mechanics, Superposition.

Superposition states that at any point when one or more states are possible, they are all true in a quantum state, which is a state where two or more physical states, until one is observed. This means the cat is alive AND dead until you look in the box, and observe it to be one way or the other.

This is just one of the fundamentals of quantum mechanics, and it is arguably one of the easier to understand. Superposition is also how quantum computers work, using a quantum bit or qubit. Typically, in computers, data is processed in “bits”, a on/of piece of information represented by either a 1 (on) or a 0 (off). In a Quantum computer, you add the qubit, which is a superpositioned state that is both a 1 and a 0. You may not understand why this is so great, but trust me, it makes quantum computers much faster and more efficient.

 Next, we will cover another of the fundamentals, Quantum Tunneling, but be warned, this is the last of the “simple” principles.

Quantum Tunneling is when a particle passes through, or “tunnels” through an object which it did not have enough energy, and therefore shouldn’t have been able to pass through. As this is sometimes hard to imagine, here's a commonly used analogy:

You have two hills, one larger than the other. You have a ball at the crest of the smaller hill, which you push down towards the larger hill. Under classic, or non-quantum physics, the ball could not pass over the larger hill as the momentum from passing down the smaller hill is not enough to reach the peak. With Quantum Physics, however, there is a very small chance that the particle, our metaphorical ball, will borrow energy from its environment, pass through the barrier (roll over the hill), and return the energy to the environment. That all may have been a bit confusing, but hopefully you followed a bit.