A qubit, short for quantum bit, is the fundamental building block of a quantum computer. A classical bit is restricted to one of two values, 0 or 1. A qubit can also exist in a superposition of both at once. This is what gives a quantum computer access to a far larger space of possibilities than a classical machine of the same size
A qubit is defined by its behaviour rather than by any single physical form. It needs two distinguishable states to serve as 0 and 1, it must be able to hold a superposition of them, and it must be able to become entangled with other qubits. Many physical systems can meet these requirements, which is why quantum computers are being built from superconducting circuits, trapped ions, neutral atoms, and electron spins, among others.
Quantum Motion encodes each qubit in the spin of a single electron held in a silicon quantum dot. This silicon spin qubit is among the smallest qubit types in development, and because it is made with standard CMOS manufacturing, it is well suited to being produced in the very large numbers a useful quantum computer will need.