### Ket 0 and Ket 1

The quantum mechanical version of a bit is a qubit, and has two basic states, **ket 0 and ket 1**. You write it as

|0⟩ and |1⟩

##### Explanation

That looks much like the well-known numbers 0 and 1, which you can save in a bit. A bit has a value of 0 **or** 1 (on or off - whatever you want to call it) but not both values.

By superposition of several qubits, different strings can be expressed *simultaneously*. In this way, four qubits can have both the value 1010 as well as 1101. In a quantum byte (8 qubits) you can store 256 series, which then again can be read out separately.

*You will say that this is not possible. *

Yet it is like that. Researchers at the Technical University (TU) of Delft managed in 2007 to perform operations with two qubits. These are the first steps on a long road to a quantum computer.

There is only one word – **incomprehensible**.

## HistoryThe British quantum physicist Paul Dirac (1902 - 1984) invented this notation. |