I can explain digital logic down to the electron in a MOSFET, but I can't come close to the same with quantum computing. This newsletter is a journal of my quest to learn the fundamentals of quantum computing and explain them on a human level.

Welcome to the Quantum Edge newsletter. Join me in my year-long journey into the weirdness that is quantum computing.

Issue 10.0, May 13, 2025

In today’s newsletter: Looking at quantum superposition

There are a number of aspects of the quantum world that are difficult to explain (if that weren’t the case, I wouldn’t be writing this newsletter). They don’t make sense in any conventional way. I call these, the nonsensicals. Today I will be talking about the first nonsensical property: superposition. Superposition is one of the keys to understanding and operating quantum computers.

Superposition: Nonsensical Number 1

Superposition means that a quantum particle can be in two states at the same time. A conventional computer bit, as I covered in issue 9.0, has two states: on or off (also known as one or zero). Qubits, based on subatomic particles (e.g., electrons) also have two states: spin-up or spin-down. I covered this toward the end of issue 9.0. Spin-up can be called a binary 1 and spin-down can be called a binary 0. Spins aren’t exactly the same thing and 0 or 1, but sometimes it helps to simplify things and call it “close enough.”

Superposition is what differentiates a bit and a qubit. A conventional computer bit is either on or off. It can only be one state at a time. If the bit does not have a charge, it is in state off. The computer logic will read it as off (a value of 0). If it has a charge, it is in state on and the computer logic will read it as on (a value 1).

A quantum computer qubit can exist in a state called superposition. In superposition, it can be in a spin-up state and a spin-down state at the same time. It will be both states, with some probability of it ultimately being one or the other.

However, you can’t read superposition. When you try to read the superposition qubit, superposition will collapse and the qubit will read as either spin-up or spin-down: one or the other, not both. So, when you are not reading the qubit, it may be in both states. When your computer hardware gets around to reading it, it will read as just one or the other state. I will discuss how that can be used to make a quantum computer in future issues.

Superposition and Schrödinger's Cat

You may have heard of Schrödinger's Cat. In pop culture, Schrödinger's Cat is a thought experiment used to help understand quantum mechanics. The story goes that there is a cat in a box with poison and until you open the box, the cat is both dead and alive. Once you open the box, the cat suddenly becomes one of the other.

If that seems like nonsense, it’s because it is nonsense. Erwin Schrödinger, the person behind the cat, originally proposed the thought experiment to show how ridiculous some of the statements being made about quantum mechanics were. He was referring to quantum speculations in 1935. Today though, people often refer to Schrödinger's Cat as though it explains everything about the quantum world.

A Real World Example of Superposition

Daydreaming might be a decent analogy. You are sitting at your desk in class. Everyone around you, including the teacher, can see you sitting there, for all intents and purposes, paying attention to the lesson. However, you are off in la la land being chased by Schrödinger's Cat who wants your help opening a box. You are in superposition. You are both awake and not awake at the same time.

When the teacher calls on you for an answer, one of two things will happen. A) you will suddenly be awake and say: “huh?” Or B) you will not stir and thus be fully asleep.

Prior to the teacher calling on you, you are both awake and not awake, Once called upon, you become just one or the other. Ponder this as an analogy for a quantum particle being in two states at the same time and only becoming definitely one state or the other when called upon for a value.

Entanglement: Nonsensical Number 2

Just a teaser on entanglement today. The next weird thing about quantum particles is called entanglement. Have you ever heard a story about identical twins who could sense when the other was having a good or a bad day despite not being together?

Entanglement is something like that. It describes two subatomic particles that can tell what state the other is in even from a distance.

Stay tuned. Next week we introduce quantum entanglement.

In Summary…

Check your email box Thursday. (Okay, some of these weekly issues have come out on Friday, or not at all. But, in a quantum world, how can you tell?)

If you received this newsletter as a forward and wish to subscribe yourself, you can do so at quantumedge.today/subscribe.

About Positive Edge LLC

Positive Edge is the consulting arm of Duane Benson, Tech journalist, Futurist, Entrepreneur. Positive Edge is your conduit to decades of leading-edge technology development, management and communications expertise.