# SimQN: a discrete-event simulator for the quantum networks
# Copyright (C) 2021-2022 Lutong Chen, Jian Li, Kaiping Xue
# University of Science and Technology of China, USTC.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
from typing import Optional
from qns.models.qubit.gate import I, X, Y, Z
import numpy as np
[docs]def PrefectStorageErrorModel(self, t: Optional[float] = 0, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The default error model for storing a qubit in quantum memory.
The default behavior is doing nothing
Args:
t: the time stored in a quantum memory. The unit it second.
decoherence_rate (float): the decoherence rate.
kwargs: other parameters
"""
pass
[docs]def DephaseStorageErrorModel(self, t: Optional[float] = 0, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The dephase error model for storing a qubit in quantum memory.
A random Z gate will be operate on the qubit with possibility: 1-e^(-decoherence_rate * t)
Args:
t: the time stored in a quantum memory. The unit it second.
decoherence_rate (float): the decoherence rate
kwargs: other parameters
"""
if decoherence_rate < 0:
raise Exception("Error decoherence rate, should be positive")
p = 1 - np.exp(-decoherence_rate * t)
self.stochastic_operate([I, Z], [1-p, p])
[docs]def DepolarStorageErrorModel(self, t: Optional[float] = 0, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The depolar error model for storing a qubit in quantum memory.
One of the random Pauli gate will be operate on the qubit with possibility:
1-e^(-decoherence_rate * t)
Args:
t: the time stored in a quantum memory. The unit it second.
decoherence_rate (float): the decoherence rate
kwargs: other parameters
"""
if decoherence_rate < 0:
raise Exception("Error decoherence rate, should be positive")
p = 1 - np.exp(-decoherence_rate * t)
if 1-3*p > 0:
self.stochastic_operate([I, X, Y, Z], [1-3*p, p, p, p])
else:
self.stochastic_operate([X, Y, Z], [1/3, 1/3, 1/3])
[docs]def PrefectTransferErrorModel(self, length: Optional[float] = 0, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The default error model for transmitting this qubit
The default behavior is doing nothing
Args:
length (float): the length of the channel
decoherence_rate (float): the decoherence rate.
kwargs: other parameters
"""
pass
[docs]def DephaseTransferErrorModel(self, length: Optional[float] = 0, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The dephase error model for transmitting a qubit in quantum channel.
A random Z gate will be operate on the qubit with possibility: 1-e^(-decoherence_rate * length)
Args:
length: the channel length
decoherence_rate (float): the decoherence rate
kwargs: other parameters
"""
if decoherence_rate < 0:
raise Exception("Error decoherence rate, should be positive")
p = 1 - np.exp(-decoherence_rate * length)
self.stochastic_operate([I, Z], [1-p, p])
[docs]def DepolarTransferErrorModel(self, length: Optional[float] = 0, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The depolar error model for transmitting a qubit in quantum channel.
One of the random Pauli gate will be operate on the qubit with possibility:
1-e^(-decoherence_rate * t)
Args:
length: the channel length
decoherence_rate (float): the decoherence rate
kwargs: other parameters
"""
if decoherence_rate < 0:
raise Exception("Error decoherence rate, should be positive")
p = 1 - np.exp(-decoherence_rate * length)
if 1-3*p > 0:
self.stochastic_operate([I, X, Y, Z], [1-3*p, p, p, p])
else:
self.stochastic_operate([X, Y, Z], [1/3, 1/3, 1/3])
[docs]def PrefectOperateErrorModel(self, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The default error model for operating this qubit.
Args:
decoherence_rate (float): the decoherence rate
"""
pass
[docs]def DephaseOperateErrorModel(self, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The dephase error model for operating this qubit.
A random Z gate will be operate on the qubit with possibility: 1-e^(-decoherence_rate)
Args:
decoherence_rate (float): the decoherence rate
"""
if decoherence_rate < 0:
raise Exception("Error decoherence rate, should be positive")
p = 1 - np.exp(-decoherence_rate)
self.stochastic_operate([I, Z], [1-p, p])
[docs]def DepolarOperateErrorModel(self, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The depolar error model for operating on a qubit.
One of the random Pauli gate will be operate on the qubit with possibility:
1-e^(-decoherence_rate * t)
Args:
decoherence_rate (float): the decoherence rate
kwargs: other parameters
"""
if decoherence_rate < 0:
raise Exception("Error decoherence rate, should be positive")
p = 1 - np.exp(-decoherence_rate)
if 1-3*p > 0:
self.stochastic_operate([I, X, Y, Z], [1-3*p, p, p, p])
else:
self.stochastic_operate([X, Y, Z], [1/3, 1/3, 1/3])
[docs]def PrefectMeasureErrorModel(self, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The default error model for measuring this qubit.
Args:
decoherence_rate (float): the decoherence rate
"""
pass
[docs]def DephaseMeasureErrorModel(self, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The dephase error model for measuring this qubit,
A random Z gate will be operate on the qubit with possibility: 1-e^(-decoherence_rate)
Args:
decoherence_rate (float): the decoherence rate
"""
if decoherence_rate < 0:
raise Exception("Error decoherence rate, should be positive")
p = 1 - np.exp(-decoherence_rate)
self.stochastic_operate([I, Z], [1-p, p])
[docs]def DepolarMeasureErrorModel(self, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The depolar error model for measuring on a qubit.
One of the random Pauli gate will be operate on the qubit with possibility:
1-e^(-decoherence_rate * t)
Args:
decoherence_rate (float): the decoherence rate
kwargs: other parameters
"""
if decoherence_rate < 0:
raise Exception("Error decoherence rate, should be positive")
p = 1 - np.exp(-decoherence_rate)
if 1-3*p > 0:
self.stochastic_operate([I, X, Y, Z], [1-3*p, p, p, p])
else:
self.stochastic_operate([X, Y, Z], [1/3, 1/3, 1/3])