What is a Qubit?

About Qubit:

• A qubit, or quantum bit, is the basic unit of information used to encode data in quantum computing.
• It can be best understood as the quantum equivalent of the traditional bit used by classical computers to encode information in binary.
  • In classical computing the information is encoded in bits, where each bit can have the value zero or one.
  • In quantum computing the information is encoded in qubits. A qubit is a two-level quantum system where the two basis qubit states are usually written as ∣0⟩ and ∣1⟩.
  • A qubit can be in state ∣0⟩, ∣1⟩, or (unlike a classical bit) in a linear combination of both states.
  • The name of this phenomenon is superposition.
• The term “qubit” is attributed to American theoretical physicist Benjamin Schumacher.
• Qubits are generally, although not exclusively, created by manipulating and measuring quantum particles (the smallest known building blocks of the physical universe), such as photons, electrons, trapped ions, superconducting circuits and atoms.
• Enabled by the unique properties of quantum mechanics, quantum computers use qubits to store more data than traditional bits, vastly improve cryptographic systems and perform very advanced computations that would take thousands of years (or be impossible) for even classical supercomputers to complete.