Gates

This submodule provides the necessary components to define and manipulate quantum gates for use in digital quantum circuits.

Simple Gates

Use these constructors to apply standard single- and two-qubit operations:

• X(qubit: int) Pauli X (bit-flip) on the specified qubit.

• Y(qubit: int) Pauli Y (bit-and-phase-flip).

• Z(qubit: int) Pauli Z (phase-flip).

• H(qubit: int) Hadamard: creates superposition.

• I(qubit: int) Identity gate: leaves the qubit unchanged.

• S(qubit: int) Phase gate (π/2 rotation about Z).

• T(qubit: int) T gate (π/4 rotation about Z).

• RX(qubit: int, theta: float | Parameter | Term) Rotation by angle theta around X.

• RY(qubit: int, theta: float | Parameter | Term) Rotation by angle theta around Y.

• RZ(qubit: int, phi: float | Parameter | Term) Rotation by angle phi around Z.

• U1(qubit: int, *, phi: float | Parameter | Term) Phase shift equivalent to RZ plus global phase.

• U2(qubit: int, *, phi: float | Parameter | Term, gamma: float | Parameter | Term) π/2 Y-rotation sandwiched by Z-rotations.

• U3(qubit: int, *, theta: float | Parameter | Term, phi: float | Parameter | Term, gamma: float | Parameter | Term) General single-qubit unitary: RZ-RY-RZ decomposition.

• SWAP(a: int, b: int) Exchanges the states of qubits a and b.

• CNOT(control: int, target: int) Controlled-X: flips target if control is 1.

• CZ(control: int, target: int) Controlled-Z: applies Z on target if control is 1.

• M(*qubits: int) Measures the listed qubits in the computational basis.

Controlled Gates

Any basic gate can be turned into a controlled gate using the Controlled class:

from qilisdk.digital.gates import Controlled, Y

controlled_y = Controlled(0, basic_gate=Y(1))
multiple_controlled_y = Controlled(0, 1, basic_gate=Y(2))

Or alternatively, you can use the .controlled() method on any gate instance:

from qilisdk.digital.gates import Y

controlled_y = Y(1).controlled(0)
multiple_controlled_y = Y(2).controlled(0, 1)

Adjoint Gates

You can create the Hermitian conjugate (dagger) of a gate either using the Adjoint class or using the .adjoint() method on any gate instance:

from qilisdk.digital.gates import Adjoint, Y

adjoint_y = Adjoint(basic_gate=Y(1))
adjoint_y = Y(1).adjoint()

Exponential Gates

To apply a gate as an exponential operator, use either the Exponential class or the .exponential() method on any gate instance:

from qilisdk.digital.gates import Exponential, Y

exp_y = Exponential(basic_gate=Y(1))
exp_y = Y(1).exponential()