Source code for discopy.quantum.ansatze

# -*- coding: utf-8 -*-

"""
Quantum circuit ans├Ątze.

Summary
-------

.. autosummary::
    :template: class.rst
    :nosignatures:
    :toctree:

    IQPansatz
    Sim14ansatz
    Sim15ansatz

"""

from discopy.matrix import get_backend
from discopy.quantum.circuit import qubit, Circuit, Id


[docs]def IQPansatz(n_qubits, params) -> Circuit: """ Build an IQP ansatz on n qubits, if n = 1 returns an Euler decomposition. >>> pprint = lambda c: print(str(c.foliation()).replace(' >>', '\\n >>')) >>> pprint(IQPansatz(3, [[0.1, 0.2], [0.3, 0.4]])) H @ H @ H >> CRz(0.1) @ qubit >> H @ CRz(0.2) >> qubit @ H @ H >> CRz(0.3) @ qubit >> qubit @ CRz(0.4) >>> print(IQPansatz(1, [0.3, 0.8, 0.4])) Rx(0.3) >> Rz(0.8) >> Rx(0.4) """ from discopy.quantum.gates import H, Rx, Rz, CRz np = get_backend() def layer(thetas): hadamards = Id().tensor(*(n_qubits * [H])) rotations = Id(qubit ** n_qubits).then(*( qubit ** i @ CRz(thetas[i]) @ qubit ** (n_qubits - 2 - i) for i in range(n_qubits - 1))) return hadamards >> rotations if n_qubits == 1: circuit = Rx(params[0]) >> Rz(params[1]) >> Rx(params[2]) elif len(np.shape(params)) != 2\ or np.shape(params)[1] != n_qubits - 1: raise ValueError( f"Expected params of shape (depth, {n_qubits - 1})") else: depth = np.shape(params)[0] circuit = Id(qubit ** n_qubits).then(*( layer(params[i]) for i in range(depth))) return circuit
[docs]def Sim14ansatz(n_qubits, params) -> Circuit: """ Builds a modified version of circuit 14 from arXiv:1905.10876 Replaces circuit-block construction with two rings of CRx gates, in opposite orientation. >>> pprint = lambda c: print(str(c.foliation()).replace(' >>', '\\n >>')) >>> pprint(Sim14ansatz(3, [[i/10 for i in range(12)]])) Ry(0) @ Ry(0.1) @ Ry(0.2) >> Controlled(Rx(0.3), distance=2) >> Controlled(Rx(0.4), distance=-1) @ qubit >> Ry(0.6) @ Controlled(Rx(0.5), distance=-1) >> qubit @ Ry(0.7) @ Ry(0.8) >> CRx(0.9) @ qubit >> Controlled(Rx(1), distance=-2) >> qubit @ CRx(1.1) >>> print(Sim14ansatz(1, [0.1, 0.2, 0.3])) Rx(0.1) >> Rz(0.2) >> Rx(0.3) """ from discopy.quantum.gates import Rx, Ry, Rz np = get_backend() def layer(thetas): sublayer1 = Id().tensor( *([Ry(theta) for theta in thetas[:n_qubits]])) for i in range(n_qubits): src = i tgt = (i - 1) % n_qubits sublayer1 = sublayer1.CRx(thetas[n_qubits + i], src, tgt) sublayer2 = Id().tensor( *([Ry(theta) for theta in thetas[2 * n_qubits: 3 * n_qubits]])) for i in range(n_qubits, 0, -1): src = i % n_qubits tgt = (i + 1) % n_qubits sublayer2 = sublayer2.CRx(thetas[-i], src, tgt) return sublayer1 >> sublayer2 params_shape = np.shape(params) if n_qubits == 1: circuit = Rx(params[0]) >> Rz(params[1]) >> Rx(params[2]) elif (len(params_shape) != 2) or (params_shape[1] != 4 * n_qubits): raise ValueError( f"Expected params of shape (depth, {4 * n_qubits})") else: depth = params_shape[0] circuit = Id(qubit ** n_qubits).then(*( layer(params[i]) for i in range(depth))) return circuit
[docs]def Sim15ansatz(n_qubits, params) -> Circuit: """ Builds a modified version of circuit 15 from arXiv:1905.10876 Replaces circuit-block construction with two rings of CNOT gates, in opposite orientation. >>> pprint = lambda c: print(str(c.foliation()).replace(' >>', '\\n >>')) >>> pprint(Sim15ansatz(3, [[0.1, 0.2, 0.3, 0.4, 0.5, 0.6]])) Ry(0.1) @ Ry(0.2) @ Ry(0.3) >> Controlled(X, distance=2) >> Controlled(X, distance=-1) @ qubit >> Ry(0.4) @ Controlled(X, distance=-1) >> qubit @ Ry(0.5) @ Ry(0.6) >> CX @ qubit >> Controlled(X, distance=-2) >> qubit @ CX >>> print(Sim15ansatz(1, [0.1, 0.2, 0.3])) Rx(0.1) >> Rz(0.2) >> Rx(0.3) """ from discopy.quantum.gates import Rx, Ry, Rz np = get_backend() def layer(thetas): sublayer1 = Id().tensor( *([Ry(theta) for theta in thetas[:n_qubits]])) for i in range(n_qubits): src = i tgt = (i - 1) % n_qubits sublayer1 = sublayer1.CX(src, tgt) sublayer2 = Id().tensor( *([Ry(theta) for theta in thetas[n_qubits:]])) for i in range(n_qubits, 0, -1): src = i % n_qubits tgt = (i + 1) % n_qubits sublayer2 = sublayer2.CX(src, tgt) return sublayer1 >> sublayer2 params_shape = np.shape(params) if n_qubits == 1: circuit = Rx(params[0]) >> Rz(params[1]) >> Rx(params[2]) elif (len(params_shape) != 2) or (params_shape[1] != 2 * n_qubits): raise ValueError( f"Expected params of shape (depth, {2 * n_qubits})") else: depth = params_shape[0] circuit = Id(qubit ** n_qubits).then(*( layer(params[i]) for i in range(depth))) return circuit