How deeply does Building Quantum Software with Python cover phase gate?

Explains amplitude signs, geometric direction, probability preservation, and a direct state-list implementation.

Phase gate

As explained in Building Quantum Software with Python

The Z gate is a single-qubit quantum gate that multiplies the amplitude of the one basis state by negative one.

The Z gate multiplies the amplitude for the |1⟩ basis state by −1 while leaving the |0⟩ amplitude unchanged. Its magnitude and probability remain the same, but its direction reverses by 180°. section 3.2.2

Apply the transformation directly to a two-amplitude single-qubit state:

Verify the reversed direction without changing the amplitude magnitude or measurement probability. section 3.2.2

State-list example

For a state whose amplitudes are represented as [sqrt(0.3), sqrt(0.7)], applying the Z gate produces [sqrt(0.3), -sqrt(0.7)].

How Building Quantum Software with Python covers it

Cover of Building Quantum Software with Python

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Also explained in

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Quantum Programming in DepthThe Z gate is the single-qubit Pauli gate that leaves ket zero unchanged and multiplies ket one by negative one.

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Related concepts

quantum gatekind of · A quantum gate is an operation that transforms the state of one or more qubits, typically represented by a unitary transformation.
target qubitconfigures · A target qubit is the qubit designated to receive or participate in the action of a quantum operation.
phase kickbackused by · Phase kickback is a quantum effect in which a controlled operation transfers a phase associated with its target to the relative phase of the control-qubit state.

This explainer was generated by Manning's knowledge graph from the text of Building Quantum Software with Python. The section links point to the parts of the book it draws on.