A quantum computer is a machine that performs its calculations by harnessing the unique features of quantum mechanics.
In ordinary computing, information is stored in bits, and each bit stores either a 0 or a 1. Many bits together can represent all sorts of information using binary code, which computers can process.
Quantum computers process quantum information, which is stored in quantum bits, called qubits (pronounced “KYU-bits”). A qubit can be any quantum object with two states – for example, a single electron (spin up or spin down) or a single photon (polarised horizontally or vertically).