How Do Quantum Computers Work? Quantum computers perform calculations based on the probability of an object's state before it is measured - instead of just 1s or 0s - which means they have the potential to process exponentially more data compared to classical computers. Classical computers carry out logical operations using the definite position of a physical state. These are usually binary, meaning its operations are based on one of two positions. A single state - such as on or off, up or down, 1 or 0 - is called a bit . In quantum computing , operations instead use the quantum state of an object to produce what's known as a qubit . These states are the undefined properties of an object before they've been detected, such as the spin of an electron or the polarisation of a photon. Rather than having a clear position, unmeasured quantum states occur in a mixed 'superposition', not unlike a coin spinning through the air before it lands in your han