Circuit

Here we present all the functions linked to the circuits for qiskit, cirq and quimb

circuit.GHZ_qiskit(circ)

Generates a GHZ state in the quantum circuit circ composed by n qubits. Acts in place.

Parameters

circ (Quantum Circuit) -- The quantum circuit in the state '00...0' where to build the GHZ

Returns

None -- Acts in place.

Return type

None

circuit.MPS_circ(qc, gates=None, init_state=None, chi=None, verbosity=False)

Function to transform a qiskit circuit qc to a quimb MPS circuit, using the gates gates

Parameters

• qc (QuantumCircuit) -- Qiskit quantum circuit to apply to the MPS

• gates (dictionary or None, optional) -- dictionary containing the gate used in the circuit in the format qiskit_gate_name: quimb_gate If None a standard set is used

• init_state (String, None or quimb.tensor.tensor_1d.MatrixProductState, optional) -- If String containing the state in computational basis, i.e. '000' or '0011' If None starts from empty state '0'x(num_qubits) If MPS in quimb format the initial state is the MPS

• chi (int, optional) -- maximum bond dimension. If None it is automatically chosen.

• verbosity (bool, optional) -- if True prints when the state is initialized. Default to false.

Returns

MPS -- quimb MPS where we have applied the quantum circuit qc starting from init_state

Return type

quimb.tensor.tensor_1d.MatrixProductState

class circuit.circ_data(circ)

Class to contain the metadata of a qiskit quantum circuit

data

data of a quantum circuit

Type

list

gates

names of the gate applied in the correct order

Type

list of string

gates_params

gate parameters. if no parameter is present it returns an empty list []

Type

list of lists

indeces

indeces to which the gates are applyed

Type

list of tuples of ints

n_qub

number of qubits in the circuit

Type

int

circuit.qft_circuit_qiskit(circuit, n)

Apply the QFT to a qiskit quantum circuit circuit in a recursive way

Parameters

• circuit (quantum circuit) -- quantum circuit where we want to apply the QFT

• n (int) -- number of qubits in circuit

Returns

None -- Acts in place

Return type

None

circuit.qft_circuit_quimb(mps, n, chi=2)

Apply the QFT to the matrix product state mps with a bond dimension of chi in a recursive way

Parameters

• mps (quimb.tensor.tensor_1d.MatrixProductState) -- Matrix product state to which we want to apply the QFT

• n (int) -- number of qubits in mps

• chi (int, optional) -- Bond dimension of the MPS. Default to 2

Returns

mps -- Matrix product state to which we have applied the QFT

Return type

quimb.tensor.tensor_1d.MatrixProductState

circuit.qft_circuit_swap_approx(state, N, verbosity=False, chi=2)

Computes the QFT of a MPS state with N qubits and a bond dimension chi.

Parameters

• state (list of ndarray) -- list of tensors of the MPS

• N (int) -- number of qubits in state

• verbosity (bool, optional) -- Default to False. If True prints applied gates

• chi (int, optional) -- Bond dimension

Returns

state -- MPS where we have applied the QFT

Return type

list of ndarray

circuit.qft_circuit_swap_cirq(qubits, circuit=[])

Build a circuit implementing the QFT algorithm on the given qubits. The order of qubits is preserved by SWAP operations. Implemented using only local operations, i.e. gates acting on neighbouring qubits. Adapted from: https://github.com/quantumlib/Cirq/blob/master/examples/quantum_fourier_transform.py and extended to n generic qubits through recursion.

Parameters

• qubits (cirq.LineQubit) -- qubits

• circuit (list) -- list of directives to create the quantum circuit

Returns

circuit -- quantum circuit where we have applied the QFT

Return type

cirq.Circuit

circuit.qft_circuit_swap_full(state, N, verbosity=False)

Computes the QFT of a MPS state with N qubits.

Parameters

• state (list of ndarray) -- list of tensors of the MPS

• N (int) -- number of qubits in state

• verbosity (bool, optional) -- Default to False. If True prints applied gates

Returns

state -- MPS where we have applied the QFT

Return type

list of ndarray