The Qubit
Instead of the bits that are used for classical computers, quantum computers use quantum bits, or qubits to represent data. While a bit is normally represented by a difference in electrical voltage, qubits are represented by quantum states of sub- atomic particles such as spin and polarization. |
 Picture from: http://qoqms.phys.strath.ac.uk/research_qc.html |
| A
qubit can be represented by a 0 or 1. The main way
that it differs from a normal bit is that it can also be both if unobserved. This is true by the principle of superposition. |
|
| In a
quantum computer, qubits are experiencing quantum
entanglement. For example, if we observe that one qubit is in an "0" state, than we know that the qubit it is entangled with is in the opposite state, so it is a "1". Quantum entanglement can be used to allow the quantum computer to do multiple operations at the same moment. |