Reference: QFT Arithmetic Qubricks

Contents

• QFTIncrement Class
• QFTAdd Class
• QFTSubtract Class
• QFTMultiply Class

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QFTIncrement Class

psiqworkbench.qubricks.qbk_qft_arithmetic.QFTIncrement

QFTIncrement(**kwargs)

Bases: Qubrick

Qubrick for incrementing a qubit register using QFT.

Follows the construction in "Quantum arithmetic with the Quantum Fourier Transform" (arxiv:1411.5949 ⧉).

compute

compute(lhs: QUInt, rhs: QUInt | int = 1, ctrl: Qubits | None = None) -> None

Compute an adder using QFT.

Note

This Qubrick does arithmetic addition, NOT modular addition.

Parameters:

Name	Type	Description	Default
lhs	Qubits	Register to be incremented.	required
rhs	(Qubits, int)	Amount to add to lhs. If a Qubits is passed, this defaults to calling QFTAdd.	1
ctrl	(Qubits, Optional)	Qubits the addition is conditioned on. Defaults to None.	None

---

QFTAdd Class

psiqworkbench.qubricks.qbk_qft_arithmetic.QFTAdd

QFTAdd(**kwargs)

Bases: Qubrick

Quantum adder implemented using QFT.

Follows the construction in "Quantum arithmetic with the Quantum Fourier Transform" (arxiv:1411.5949 ⧉).

compute

compute(lhs: QUInt, rhs: QUInt | int, ctrl: Qubits | None = None) -> None

Compute an adder using QFT.

Note

This Qubrick does arithmetic addition, NOT modular addition.

Parameters:

Name	Type	Description	Default
lhs	QUInt	Register to be added to.	required
rhs	(QUInt, int)	Amount to add to lhs. If an int is passed, this defaults to calling QFTIncrement.	required
ctrl	(Qubits, Optional)	Qubits the addition is conditioned on. Defaults to None.	None

---

QFTSubtract Class

psiqworkbench.qubricks.qbk_qft_arithmetic.QFTSubtract

QFTSubtract(**kwargs)

Bases: Qubrick

Quantum subtractor implemented using QFT.

compute

compute(target_qubits: QUInt, subtraction_amount: QUInt | int, cond: int = 0)

Compute a subtractor using QFT using reversed phase adder.

Parameters:

Name	Type	Description	Default
target_qubits	QUInt	Register to be added to.	required
subtraction_amount	(QUInt, int)	Amount to subtract from target_qubits. If an int is passed, this defaults to calling QFTIncrement.	required
cond	(Qubits, int)	Qubits the subtraction is conditioned on.	0

---

QFTMultiply Class

psiqworkbench.qubricks.qbk_qft_arithmetic.QFTMultiply

QFTMultiply(**kwargs)

Bases: Qubrick

Quantum multiplier implemented using QFT.

Follows the construction in "Quantum arithmetic with the Quantum Fourier Transform" (arxiv:1411.5949 ⧉).

compute

compute(a: QUInt, b: QUInt, cond: Qubits | int = 0)

Compute multiplication using QFT.

Notes

• Only works if a.num_qubits = b.num_qubits = n
• Allocates a fresh output register consisting of \(2n\) qubits.

Parameters:

Name	Type	Description	Default
a	QUInt	First register to be multiplied.	required
b	QUInt	Second register to be multiplied.	required
cond	(Qubits, int)	Qubits the addition is conditioned on. Defaults to 0.	0