Qubit
The fundamental unit of quantum information, analogous to a classical bit but capable of existing in superposition of 0 and 1 states.
A qubit (quantum bit) is the basic unit of quantum information. Unlike classical bits that must be either 0 or 1, qubits can exist in superposition of both states simultaneously, described by complex probability amplitudes. When measured, a qubit collapses to either 0 or 1 with probabilities determined by its amplitudes. Qubits can also be entangled, creating correlations between particles that enable quantum algorithms. Physical implementations include superconducting circuits (IBM, Google), trapped ions (IonQ, Quantinuum), and photonic systems.
Also known as
quantum bit, qubits