Artificial Intelligence By Example

Representing a qubit

The mathematical representation of a qubit is:

• |0〉 for a 0 value
• |1〉 for a 1 value
• α|0〉 where alpha is a probability parameter
• β|1〉 where beta is a probability parameter

These brackets are called bracket or bra-ket notation.

This linear representation is called superposition. In itself, it explains most of the power of quantum computing. 

The superposition of 0 and 1 in a quantum state can thus be expressed as follows in kets such as |1> and not bras such as in <1|:

The alpha and beta probabilities look like weights and the total probabilities of those probable states of qubit must add up to 1. We use partition functions, ...