Reference: Uniform State Preparation (USP) Qubricks¶

Contents¶

USP Class
ZAUSP Class
IUSP Class
USP_RUS Class

USP Class¶

psiqworkbench.qubricks.qbk_usp.USP ¶

USP(**kwargs)

Bases: Qubrick

Qubrick for Uniform State Preparation.

Follows the construction described in Fig.12 in "Encoding Electronic Spectra in Quantum Circuits with Linear T Complexity" (arXiv:1805.03662 ⧉).

compute ¶

compute(d: int, target_qreg: Qubits | None = None, error_param: float = 0)

Prepare a uniformly distributed state.

Parameters:

Name	Type	Description	Default
`d`	`int`	Desired number of basis states in the superposition.	required
`target_qreg`	`Qubits or None`	The register to operate on, or None to allocate a new register.	`None`
`error_param`	`float`	A parameter to control the precision of the rotation angle in reflect. Defaults to 0 (no error).	`0`

Raises:

Type	Description
`RuntimeError`	If the register passed in is too small.

Note

For more details, see Built-in Qubricks tutorial.

ZAUSP Class¶

psiqworkbench.qubricks.qbk_usp.ZAUSP ¶

ZAUSP(**kwargs)

Bases: Qubrick

Qubrick for Uniform State Preparation.

The routine which uses zero auxiliary qubits from "An efficient quantum algorithm for preparation of uniform quantum superposition states" (arxiv:2306.11747 ⧉).

compute ¶

compute(d: int, target_qreg: Qubits | None = None, error_param: float = 0)

Prepare a uniformly distributed state.

Parameters:

Name	Type	Description	Default
`d`	`int`	Desired number of basis states in the superposition.	required
`target_qreg`	`Qubits or None`	The register to operate on, or None to allocate a new register.	`None`
`error_param`	`float`	A parameter to control the precision of individual rotations. Defaults to 0 (no error).	`0`

Raises:

Type	Description
`RuntimeError`	If the register passed in is too small.

Note

For more details, see Built-in Qubricks tutorial.

IUSP Class¶

psiqworkbench.qubricks.qbk_usp.IUSP ¶

IUSP(**kwargs)

Bases: Qubrick

Qubrick for improved Uniform State Preparation.

compute ¶

compute(d: int, target_qreg: Qubits | None = None, error_param: float = 0)

Prepare a uniformly distributed state.

Parameters:

Name	Type	Description	Default
`d`	`int`	Desired number of basis states in the superposition.	required
`target_qreg`	`Qubits or None`	The register to operate on, or None to allocate a new register.	`None`
`error_param`	`float`	A parameter to control the precision of individual rotations. Defaults to 0 (no error).	`0`

Raises:

Type	Description
`RuntimeError`	If the register passed in is too small.

Note

error_param is currently used for quantifying error budget per rotation, but this could change.

USP_RUS Class¶

psiqworkbench.qubricks.qbk_usp.USP_RUS ¶

USP_RUS(use_jump_control: bool = False, max_num_loops: int = 100, **kwargs)

Bases: Qubrick

Qubrick for Uniform State Preparation, repeat-until-success variant.

This qubrick currently requires the >>jump-control>> filter to exist in your pipeline.

Note

This version of USP is not deterministically reversible and thus cannot be used in settings where we need this reversibility, for example, in PREP of LCU's.

Parameters:

Name	Type	Description	Default
`use_jump_control`	`bool`	Use (currently experimental) jump opcodes	`False`
`max_num_loops`	`int`	The maximum number of loops to try before failing. Note that USP_RUS always has a success rate greater than 50%; the chance of it requiring 100 attempts is vanishingly small.	`100`

compute ¶

compute(d: int, target_qreg: Qubits | None = None, **kwargs)

Prepare a uniformly distributed state.

Parameters:

Name	Type	Description	Default
`d`	`int`	Desired number of basis states in the superposition.	required
`target_qreg`	`Qubits or None`	The register to operate on, or None to allocate a new register.	`None`

Raises:

Type	Description
`RuntimeError`	If the register passed in is too small.