Learn quantum computing, without the hype
A curated map of the best free and paid resources, organised into three levels and 42 topics. Tell it what you want to learn and it hands you the right links — in the right order.
Three paths, one field
Each level is a complete route with its own prerequisites, topics and quiz. If you are not sure where you sit, take the beginner quiz — it takes five minutes and tells you honestly.
Beginner
You have never touched quantum computing. This level uses pictures, analogies and probability — no linear algebra. The goal is that you can explain what a qubit is to a friend, and that you know what quantum computers genuinely cannot do.
Intermediate
You know the words. Now you learn the notation behind them: complex amplitudes, vectors, matrices and Dirac notation. You will write Qiskit or PennyLane code and run it on real quantum hardware, and you will understand Grover and Shor rather than just naming them.
Advanced
You are comfortable with the math and want to work in the field. This level covers quantum error correction, fault tolerance, complexity theory, Hamiltonian simulation and the variational algorithms that dominate current research — and points you at the primary literature.
Looking for something specific?
Every topic has its own page: a one-sentence definition, what you need to know first, what you will be able to do afterwards, and an ordered reading list with the best resource pinned to the top.
What is quantum computing?
A computer that stores and manipulates information using quantum physics, letting it explore many computational paths at once and interfere them so the wrong answers cancel out.
BeginnerQubits
The quantum version of a bit. Instead of being 0 or 1, a qubit carries two numbers (amplitudes) that say how much of "0" and how much of "1" it holds — including negative and complex values.
BeginnerSuperposition
A qubit holding a nonzero amount of both 0 and 1 at the same time — not "secretly one of them", and not "both in separate universes", but a genuine third kind of state with no classical counterpart.
BeginnerEntanglement
Two or more qubits sharing a single joint state, so that their measurement results are correlated in ways no classical shared-secret arrangement can reproduce — even though neither qubit has a definite state of its own.
BeginnerMath prerequisites
To go past intuition you need complex numbers, vectors, matrices, inner products and eigenvectors. That is roughly one solid linear algebra course — not a physics degree.
BeginnerWhat quantum computers can’t do
Quantum computers give large speedups on a narrow, structured set of problems. They are not faster at general computing, they do not "solve NP-complete problems instantly", and they will not run your spreadsheet.
BeginnerThe core ideas, in plain language
12 concept cards covering what a qubit actually is, why superposition is not parallelism, and why entanglement cannot send messages. Each one is built around the misconception it exists to correct — no math required.
A qubit is not "a bit that is 0 and 1 at the same time"
A classical bit is one number that is either 0 or 1. A qubit is described by two numbers — one attached to the outcome 0, one attached to the outcome 1. Those numbers are called amplitudes, and they can be negative, or even complex.
Concept cardAmplitudes can cancel. Probabilities cannot.
To get the probability of an outcome, you square the size of its amplitude. Because amplitudes can be negative, two contributions to the same outcome can add up to zero — an event that could have happened two ways can end up never happening at all.
Concept cardSuperposition is not "trying every answer at once"
A quantum computer with n qubits does hold amplitudes for all 2^n possible bit strings simultaneously. But measuring gives you exactly one of them, chosen at random. Holding all the answers is useless unless you can arrange for the right one to be the likely one.
Concept cardMeasurement destroys what it reads
When you measure a qubit you get one classical bit, with probability equal to the amplitude squared. Afterwards the qubit is simply in the state you measured — the other amplitude is gone forever. You cannot measure it again to learn more.
Concept cardInterference is the actual source of speedup
A quantum algorithm arranges the computation so that the amplitudes leading to wrong answers cancel out, while those leading to the right answer reinforce. When you finally measure, the right answer is overwhelmingly likely.
Concept cardEntanglement cannot send messages
Two entangled qubits give perfectly correlated results no matter how far apart they are. But each individual result is random, and you cannot choose what you get. Only by comparing notes over an ordinary channel do the correlations become visible.
Concept card