def main():
# Number of sites in the Fermi-Hubbard model (2*n_site spin orbitals)
n_site = 4
# Number of fermions
n_fermi = 4
# Hopping strength between neighboring sites
t = 1.0
# On-site interaction strength. It has to be negative (attractive) for the
# BCS theory to work.
u = -4.0
# Calculate the superconducting gap and the angles for BCS
delta, bog_theta = bcs_parameters(n_site, n_fermi, u, t)
# Initializing the qubits on a ladder
upper_qubits = [cirq.GridQubit(0, i) for i in range(n_fermi)]
lower_qubits = [cirq.GridQubit(1, i) for i in range(n_fermi)]
print('Quantum circuits to prepare the BCS meanfield state.')
print('Number of sites = ', n_site)
print('Number of fermions = ', n_fermi)
print('Tunneling strength = ', t)
print('On-site interaction strength = ', u)
print('Superconducting gap = ', delta, '\n')
bog_circuit = cirq.Circuit(
bogoliubov_trans(upper_qubits[i], lower_qubits[i], bog_theta[i])
for i in range(n_site))
bog_circuit = cirq_google.optimized_for_xmon(bog_circuit)
print('Circuit for the Bogoliubov transformation:')
print(bog_circuit.to_text_diagram(transpose=True), '\n')
# The inverse fermionic Fourier transformation on the spin-up states
print((
'Circuit for the inverse fermionic Fourier transformation on the spin-up states:'
))
fourier_circuit_spin_up = cirq.Circuit(
fermi_fourier_trans_inverse_4(upper_qubits),
strategy=cirq.InsertStrategy.EARLIEST)
fourier_circuit_spin_up = cirq_google.optimized_for_xmon(
fourier_circuit_spin_up)
print(fourier_circuit_spin_up.to_text_diagram(transpose=True), '\n')
# The inverse fermionic Fourier transformation on the spin-down states
print((
'Circuit for the inverse fermionic Fourier transformation on the spin-down states:'
))
fourier_circuit_spin_down = cirq.Circuit(
fermi_fourier_trans_inverse_conjugate_4(lower_qubits),
strategy=cirq.InsertStrategy.EARLIEST)
fourier_circuit_spin_down = cirq_google.optimized_for_xmon(
fourier_circuit_spin_down)
print(fourier_circuit_spin_down.to_text_diagram(transpose=True))
def main(*, num_qubits: int, depth: int, num_circuits: int, seed: int,
routes: int):
"""Run the quantum volume algorithm with a preset configuration.
See the calculate_quantum_volume documentation for more details.
Args:
num_qubits: Pass-through to calculate_quantum_volume.
depth: Pass-through to calculate_quantum_volume
num_circuits: Pass-through to calculate_quantum_volume
seed: Pass-through to calculate_quantum_volume
Returns: Pass-through from calculate_quantum_volume.
"""
device = cirq_google.Bristlecone
compiler = lambda circuit: cirq_google.optimized_for_xmon(circuit=circuit)
noisy = cirq.DensityMatrixSimulator(noise=cirq.ConstantQubitNoiseModel(
qubit_noise_gate=cirq.DepolarizingChannel(p=0.005)))
calculate_quantum_volume(
num_qubits=num_qubits,
depth=depth,
num_circuits=num_circuits,
random_state=seed,
device_graph=routing.gridqubits_to_graph_device(device.qubits),
samplers=[cirq.Simulator(), noisy],
routing_attempts=routes,
compiler=compiler,
)
def test_remap_qubits():
before = cirq.Circuit([cirq.Moment([cirq.CZ(cirq.LineQubit(0), cirq.LineQubit(1))])])
after = cg.optimized_for_xmon(before, qubit_map=lambda q: cirq.GridQubit(q.x, 0))
assert after == cirq.Circuit(
[cirq.Moment([cirq.CZ(cirq.GridQubit(0, 0), cirq.GridQubit(1, 0))])]
)
def test_ccz():
before = cirq.Circuit(
cirq.CCZ(cirq.GridQubit(5, 5), cirq.GridQubit(5, 6), cirq.GridQubit(5, 7))
)
after = cg.optimized_for_xmon(before)
assert len(after) <= 22
assert_circuits_with_terminal_measurements_are_equivalent(before, after, atol=1e-4)
def test_remap_qubits():
before = cirq.Circuit([cirq.Moment([cirq.CZ(cirq.LineQubit(0), cirq.LineQubit(1))])])
with cirq.testing.assert_deprecated(
'Use cirq.optimize_for_target_gateset', deadline='v0.16', count=2
):
after = cg.optimized_for_xmon(before, qubit_map=lambda q: cirq.GridQubit(q.x, 0))
assert after == cirq.Circuit(
[cirq.Moment([cirq.CZ(cirq.GridQubit(0, 0), cirq.GridQubit(1, 0))])]
)
def test_swap_field(n: int, d: int):
before = cirq.Circuit(
cirq.ISWAP(cirq.LineQubit(j), cirq.LineQubit(j + 1)) for i in range(d)
for j in range(i % 2, n - 1, 2))
before.append(cirq.measure(*before.all_qubits()))
after = cg.optimized_for_xmon(before)
assert len(after) == d * 4 + 2
if n <= 5:
assert_circuits_with_terminal_measurements_are_equivalent(before,
after,
atol=1e-4)
def test_ccz():
before = cirq.Circuit(
cirq.CCZ(cirq.GridQubit(5, 5), cirq.GridQubit(5, 6), cirq.GridQubit(5, 7))
)
with cirq.testing.assert_deprecated(
'Use cirq.optimize_for_target_gateset', deadline='v0.16', count=2
):
after = cg.optimized_for_xmon(before)
assert len(after) <= 22
assert_circuits_with_terminal_measurements_are_equivalent(before, after, atol=1e-4)
def test_swap_field(n: int, d: int):
before = cirq.Circuit(
cirq.ISWAP(cirq.LineQubit(j), cirq.LineQubit(j + 1))
for i in range(d)
for j in range(i % 2, n - 1, 2)
)
before.append(cirq.measure(*before.all_qubits()))
with cirq.testing.assert_deprecated(
'Use cirq.optimize_for_target_gateset', deadline='v0.16', count=2
):
after = cg.optimized_for_xmon(before)
assert len(after) == d * 4 + 2
if n <= 5:
assert_circuits_with_terminal_measurements_are_equivalent(before, after, atol=1e-4)
def test_allow_partial_czs():
before = cirq.Circuit([
cirq.Moment([cirq.CZ(cirq.GridQubit(5, 5), cirq.GridQubit(5, 6))**0.5])
])
after = cg.optimized_for_xmon(before, allow_partial_czs=True)
cz_gates = [
op.gate for op in after.all_operations()
if isinstance(op, cirq.GateOperation)
and isinstance(op.gate, cirq.CZPowGate)
]
num_full_cz = sum(1 for cz in cz_gates if cz.exponent % 2 == 1)
num_part_cz = sum(1 for cz in cz_gates if cz.exponent % 2 != 1)
assert num_full_cz == 0
assert num_part_cz == 1
def test_adjacent_cz_get_split_apart():
before = cirq.Circuit([
cirq.Moment([
cirq.CZ(cirq.GridQubit(0, 0), cirq.GridQubit(0, 1)),
cirq.CZ(cirq.GridQubit(1, 0), cirq.GridQubit(1, 1)),
])
])
after = cg.optimized_for_xmon(before, new_device=cg.Foxtail)
assert after == cirq.Circuit(
[
cirq.Moment([cirq.CZ(cirq.GridQubit(0, 0), cirq.GridQubit(0, 1))]),
cirq.Moment([cirq.CZ(cirq.GridQubit(1, 0), cirq.GridQubit(1, 1))]),
],
device=cg.Foxtail,
)
def main():
print("Length 10 line on Bristlecone:")
line = cirq_google.line_on_device(cirq_google.Bristlecone, length=10)
print(line)
print("Initial circuit:")
n = 10
depth = 2
circuit = cirq.Circuit(
cirq.SWAP(cirq.LineQubit(j), cirq.LineQubit(j + 1))
for i in range(depth) for j in range(i % 2, n - 1, 2))
circuit.append(cirq.measure(*cirq.LineQubit.range(n), key='all'))
print(circuit)
print()
print("Xmon circuit:")
translated = cirq_google.optimized_for_xmon(circuit=circuit,
qubit_map=lambda q: line[q.x])
print(translated)
def test_allow_partial_czs():
before = cirq.Circuit(
[cirq.Moment([cirq.CZ(cirq.GridQubit(5, 5), cirq.GridQubit(5, 6)) ** 0.5])]
)
with cirq.testing.assert_deprecated(
'Use cirq.optimize_for_target_gateset', deadline='v0.16', count=2
):
after = cg.optimized_for_xmon(before, allow_partial_czs=True)
cz_gates = [
op.gate
for op in after.all_operations()
if isinstance(op, cirq.GateOperation) and isinstance(op.gate, cirq.CZPowGate)
]
num_full_cz = sum(1 for cz in cz_gates if cz.exponent % 2 == 1)
num_part_cz = sum(1 for cz in cz_gates if cz.exponent % 2 != 1)
assert num_full_cz == 0
assert num_part_cz == 1
