 Qubit

A qubit is a two-dimensional quantum system. Its pure state is a ray in a two-dimensional complex Hilbert space and may be written $\alpha |0⟩+\beta |1⟩$ with $|\alpha {|}^2+|\beta {|}^2=1$.

A qubit, or quantum bit, is the fundamental unit of quantum information in quantum computing. Unlike a classical bit, which can represent a value of either 0 or 1, a qubit can exist in a superposition of both states at the same time. This property allows quantum computers to perform complex calculations more efficiently than classical computers for certain problems.