PolynomialPauliRotations

class qiskit.circuit.library.PolynomialPauliRotations(num_state_qubits=None, coeffs=None, basis='Y', name='poly')

Bases: FunctionalPauliRotations

A circuit implementing polynomial Pauli rotations.

For a polynomial \(p(x)\), a basis state \(|i\rangle\) and a target qubit \(|0\rangle\) this operator acts as:

\[|i\rangle |0\rangle \mapsto \cos\left(\frac{p(i)}{2}\right) |i\rangle |0\rangle + \sin\left(\frac{p(i)}{2}\right) |i\rangle |1\rangle\]

Let n be the number of qubits representing the state, d the degree of p(x) and q_i the qubits, where q_0 is the least significant qubit. Then for

\[x = \sum_{i=0}^{n-1} 2^i q_i,\]

we can write

\[p(x) = \sum_{j=0}^{j=d} c_j x^j\]

where \(c\) are the input coefficients, coeffs.

Prepare an approximation to a state with amplitudes specified by a polynomial.

Parameters:

• num_state_qubits (int | None) – The number of qubits representing the state.

• coeffs (list[float] | None) – The coefficients of the polynomial. coeffs[i] is the coefficient of the i-th power of x. Defaults to linear: [0, 1].

• basis (str) – The type of Pauli rotation (‘X’, ‘Y’, ‘Z’).

• name (str) – The name of the circuit.

Attributes

ancillas

Returns a list of ancilla bits in the order that the registers were added.

basis

The kind of Pauli rotation to be used.

Set the basis to ‘X’, ‘Y’ or ‘Z’ for controlled-X, -Y, or -Z rotations respectively.

Returns:

The kind of Pauli rotation used in controlled rotation.

calibrations

Return calibration dictionary.

The custom pulse definition of a given gate is of the form {'gate_name': {(qubits, params): schedule}}

clbits

Returns a list of classical bits in the order that the registers were added.

coeffs

The coefficients of the polynomial.

coeffs[i] is the coefficient of the i-th power of the function input \(x\), that means that the rotation angles are based on the coefficients value, following the formula

\[c_j x^j , j=0, ..., d\]

where \(d\) is the degree of the polynomial \(p(x)\) and \(c\) are the coefficients coeffs.

Returns:

The coefficients of the polynomial.

data

degree

Return the degree of the polynomial, equals to the number of coefficients minus 1.

Returns:

The degree of the polynomial. If the coefficients have not been set, return 0.

extension_lib = 'include "qelib1.inc";'

global_phase

Return the global phase of the current circuit scope in radians.

header = 'OPENQASM 2.0;'

instances = 271

layout

Return any associated layout information about the circuit

This attribute contains an optional TranspileLayout object. This is typically set on the output from transpile() or PassManager.run() to retain information about the permutations caused on the input circuit by transpilation.

There are two types of permutations caused by the transpile() function, an initial layout which permutes the qubits based on the selected physical qubits on the Target, and a final layout which is an output permutation caused by SwapGates inserted during routing.

metadata

The user provided metadata associated with the circuit.

The metadata for the circuit is a user provided dict of metadata for the circuit. It will not be used to influence the execution or operation of the circuit, but it is expected to be passed between all transforms of the circuit (ie transpilation) and that providers will associate any circuit metadata with the results it returns from execution of that circuit.

num_ancilla_qubits

The minimum number of ancilla qubits in the circuit.

Returns:

The minimal number of ancillas required.

num_ancillas

Return the number of ancilla qubits.

num_clbits

Return number of classical bits.

num_parameters

num_qubits

Return number of qubits.

num_state_qubits

The number of state qubits representing the state \(|x\rangle\).

Returns:

The number of state qubits.

op_start_times

Return a list of operation start times.

This attribute is enabled once one of scheduling analysis passes runs on the quantum circuit.

Returns:

List of integers representing instruction start times. The index corresponds to the index of instruction in QuantumCircuit.data.

Raises:

AttributeError – When circuit is not scheduled.

parameters

prefix = 'circuit'

qregs: list[QuantumRegister]

A list of the quantum registers associated with the circuit.

qubits

Returns a list of quantum bits in the order that the registers were added.