# Copyright 2021 Huawei Technologies Co., Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
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# ============================================================================
"""General GHZ State."""
from mindquantum.core.circuit import Circuit
from mindquantum.core.gates import H, X
from mindquantum.utils.type_value_check import _check_input_type
[docs]def general_ghz_state(qubits):
r"""
Circuit that prepare a general GHZ State based on zero state.
The GHZ State is defined as the equality superposition of three zeros state
and three ones state:
.. math:
\left\text{GHZ}\right> = (\left|000\right> + \left|111\right>)/\sqrt{2}
Here in this API, we can create a general GHZ state on arbitrary sub qubits of
any total qubits.
Args:
qubits (list[int]): Qubits you want to apply general GHZ state.
Examples:
>>> from mindquantum.algorithm.library import general_ghz_state
>>> print(general_ghz_state(range(3)).get_qs(ket=True))
√2/2¦000⟩
√2/2¦111⟩
>>> print(general_ghz_state([1, 2]).get_qs(ket=True))
√2/2¦000⟩
√2/2¦110⟩
Returns:
Circuit, circuit that can prepare ghz state.
"""
_check_input_type('qubits', (list, range), qubits)
circuit = Circuit()
for i, qubit in enumerate(qubits):
if i == 0:
circuit += H.on(qubit)
else:
circuit += X.on(qubit, qubits[i - 1])
return circuit