valid_stabilizer_state_preparation

guppyft.verify.valid_stabilizer_state_preparation(semantic_function: SemanticStabilizerState | SemanticStabilizerStateDouble, impl_function: ImplementationStabilizerState | ImplementationStabilizerStateDouble, code_definition: StabilizerCode, n_impl_ancillas: int | None = None) → bool[source]

Checks whether impl_function is a valid implementation of semantic_function.

Validates the implementation of a logical state preparation function. The program must contain only Clifford gates and measurements. The resulting state may be on a single code block or entangle two code blocks.

Parameters:

  • semantic_function – A Guppy function for semantic action of Pauli eigenstate preparation over one or two code blocks.

  • impl_function – A Guppy function for preparing the logical eigenstate over one or two code blocks.

  • code_definition – A stabilizer code with well-defined \([[n, k, d]]\) parameters, stabilizer generators, and logical operators.

  • n_impl_ancillas – The number of ancilla qubits used in the implementation. Defaults to None meaning that no ancilla qubits are used by default.

Returns:

A Boolean indicating whether the state preparation is valid.

from guppylang import guppy
from guppylang.std.builtins import array
from guppylang.std.quantum import cx, h, qubit

from guppyft.code_def import StabilizerCode
from guppyft.verify import valid_stabilizer_state_preparation

CSS_4Q_DEF = StabilizerCode.from_python_strings(
    n_physical_qubits=4,
    n_logical_qubits=2,
    distance=2,
    generators=["XXXX", "ZZZZ"],
    x_logicals=["XXII", "XIXI"],
    z_logicals=["IZIZ", "IIZZ"],
)


@guppy
def specify_zero_state() -> array[qubit, 2]:
    return array(qubit() for _ in range(2))


@guppy
def implement_non_ft_zero_state() -> array[qubit, 4]:
    block = array(qubit() for _ in range(4))
    h(block[0])
    cx(block[0], block[1])
    cx(block[0], block[2])
    cx(block[0], block[3])
    return block


assert valid_stabilizer_state_preparation(
    specify_zero_state,
    implement_non_ft_zero_state,
    CSS_4Q_DEF,
)