StatePreparation

class StatePreparation(params, num_qubits=None, inverse=False, label=None)

Bases: Gate

Complex amplitude state preparation.

Class that implements the (complex amplitude) state preparation of some flexible collection of qubit registers.

Parameters

• params (Union[str, list, int, Statevector]) –

  • Statevector: Statevector to initialize to.

  • list: vector of complex amplitudes to initialize to.

  • string: labels of basis states of the Pauli eigenstates Z, X, Y. See Statevector.from_label(). Notice the order of the labels is reversed with respect to the qubit index to be applied to. Example label ‘01’ initializes the qubit zero to \(|1\rangle\) and the qubit one to \(|0\rangle\).

  • int: an integer that is used as a bitmap indicating which qubits to initialize to \(|1\rangle\). Example: setting params to 5 would initialize qubit 0 and qubit 2 to \(|1\rangle\) and qubit 1 to \(|0\rangle\).

• num_qubits (Optional[int]) – This parameter is only used if params is an int. Indicates the total number of qubits in the initialize call. Example: initialize covers 5 qubits and params is 3. This allows qubits 0 and 1 to be initialized to \(|1\rangle\) and the remaining 3 qubits to be initialized to \(|0\rangle\).

• inverse (bool) – if True, the inverse state is constructed.

• label (Optional[str]) – An optional label for the gate

Raises

QiskitError – num_qubits parameter used when params is not an integer

When a Statevector argument is passed the state is prepared using a recursive initialization algorithm, including optimizations, from [1], as well as some additional optimizations including removing zero rotations and double cnots.

References: [1] Shende, Bullock, Markov. Synthesis of Quantum Logic Circuits (2004) [https://arxiv.org/abs/quant-ph/0406176v5]

Methods Defined Here

broadcast_arguments	Validation and handling of the arguments and its relationship.
inverse	Return inverted StatePreparation
validate_parameter	StatePreparation instruction parameter can be str, int, float, and complex.

Attributes

condition_bits

Get Clbits in condition.

decompositions

Get the decompositions of the instruction from the SessionEquivalenceLibrary.

definition

Return definition in terms of other basic gates.

duration

Get the duration.

label

Return instruction label

name

Return the name.

num_clbits

Return the number of clbits.

num_qubits

Return the number of qubits.

params

return instruction params.

unit

Get the time unit of duration.