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# 5.2.1 The NOT gate

The NOT gate is denoted by the operator, and, in the basis of the logical qubits and , is represented by the matrix

which is also the Pauli-X operator, , mentioned earlier. In a circuit diagram representing a quantum algorithm, the symbol for the NOT gate is shown in Figure 7.

Figure 7 The symbol used in a quantum circuit for a NOT gate,

In quantum computing, the truth table specifies outcomes for the logical states and . In Table 3 the general superposition state is also included for reference.

## Table 3 Quantum NOT gate truth table

Input | Output

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