Quantum Computing 101: From Zero to Your First Circuit

A course here means a curated order to read this site’s free tutorials in, not a separate product. Every module below is a tutorial you can already read for nothing. What the course adds is the sequence and the connective tissue. There is no signup, no assessment and no certificate, and the stated length is the sum of the modules’ own reading times. Running the code yourself will take longer.

Most introductions to quantum computing fail the same way. They open with a metaphor about a coin spinning in the air, spend three chapters on it, and leave you unable to read a single line of a real circuit. This one does not do that.

Quantum Computing 101 is free, self-paced, and built around the interactive tools on this site. You will spend as much time clicking on a live Bloch sphere and building circuits as you will reading. By the end you will have written and run a quantum circuit in Qiskit and you will understand exactly what it did.

Who this is for

You can program a little (Python is ideal, but any language will do) and you are comfortable with school-level trigonometry. You do not need quantum mechanics, and you do not need a physics background. Every piece of mathematics is introduced where it is used.

What you will be able to do

• Read any single-qubit state off a Bloch sphere and say what a measurement would do to it
• Explain what every common gate does, geometrically, without memorising a matrix
• Write, run and debug a real circuit in Qiskit
• Build and interpret an entangled Bell pair
• Say honestly what a quantum computer is and is not good for, and not be fooled by hype

The curriculum

Module 1: What a qubit really is. Start with what a qubit is, and kill the “it is both 0 and 1 at once” myth before it takes root.

Module 2: The language. Bra-ket notation, so the rest of the field stops looking like hieroglyphics.

Module 3: The maths you actually need. Linear algebra for quantum computing. Vectors, matrices, inner products. Nothing you will not use.

Module 4: Reading the Bloch sphere. How to read the Bloch sphere, the single most useful picture in the field, driven live in the simulator.

Module 5: Gates are rotations. The Pauli gates, where X, Y and Z stop being matrices and become half-turns you can watch.

Module 6: Superposition and phase. Hadamard, S and T, and why phase is where the real work happens.

Module 7: The full gate set. Quantum gates explained, including the two-qubit gates the Bloch sphere cannot draw.

Module 8: Your first circuit. Build a quantum circuit in Qiskit. Code, run, measure, interpret the counts.

Module 9: Entanglement. Quantum entanglement explained, the resource that makes any of this worth doing.

How to take it

Work through the modules in order. Each one is a standalone tutorial with runnable code, so you can stop and restart whenever you like. Everything runs in your browser or in a free local Python environment. There is nothing to install to get started and nothing to pay, ever.

When you finish, Quantum Computing 201 picks up exactly where this leaves off.