# 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.const import QUBIT_STATE_0
from qns.models.qubit.gate import I, X, Y, Z
import numpy as np
from qns.models.qubit.qubit import QState
from qns.utils.rnd import get_rand
[docs]def PrefectError(self, p: Optional[float] = 0, **kwargs):
"""
The default error model for this qubit.
Args:
p (float): the error possibility
"""
pass
[docs]def DephaseError(self, p: Optional[float] = 0, **kwargs):
"""
The dephase error model.
A random Z gate will be operate on the qubit with possibility p.
Args:
p (float): the error possibility
"""
if p < 0 or p > 1:
raise Exception("Error decoherence rate, should be in [0, 1]")
self.stochastic_operate([I, Z], [1-p, p])
[docs]def DepolarError(self, p: Optional[float] = 0, **kwargs):
"""
The depolarizing error model.
One of the random Pauli gate will be operate on the qubit with possibility p :
Args:
p (float): the error possibility
kwargs: other parameters
"""
if p < 0 or p > 1:
raise Exception("Error decoherence rate, should be in [0, 1]")
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 BitFlipError(self, p: Optional[float] = 0, **kwargs):
"""
The bit flip error model.
Args:
p (float): the error possibility, [0, 1]
kwargs: other parameters
"""
if p < 0 or p > 1:
raise Exception("Error decoherence rate, should be in [0, 1]")
self.stochastic_operate([I, X], [1-p, p])
[docs]def DissipationError(self, p: Optional[float] = 0, **kwargs):
"""
The dissipation error model.
Args:
p (float): the error possibility, [0, 1]
kwargs: other parameters
"""
if p < 0 or p > 1:
raise Exception("Error decoherence rate, should be in [0, 1]")
real_p = get_rand()
if real_p < p:
self.measure()
self.state = QState([self], state=QUBIT_STATE_0)
[docs]def ErrorWithTime(ErrorModel):
"""generate the error. The error possibility is 1-e^{-decoherence_rate * t}"""
def GeneratedErrorWithTime(self, t: Optional[float] = 0, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The error model with time for this qubit. The error possibility is 1-e^{-decoherence_rate * t}.
Args:
t (float): the during time in second.
decoherence_rate (float): the decoherence rate.
"""
p = 1 - np.exp(-decoherence_rate * t)
ErrorModel(self, p, **kwargs)
return GeneratedErrorWithTime
[docs]def ErrorWithLength(ErrorModel):
"""generate the error. The error possibility is 1-e^{-decoherence_rate * length}"""
def GeneratedErrorWithLength(self, length: Optional[float] = 0, decoherence_rate: Optional[float] = 0, **kwargs):
"""
The error model with length for this qubit. The error possibility is 1-e^{-decoherence_rate * length}.
Args:
length (float): the transmission length in meter.
decoherence_rate (float): the decoherence rate.
"""
p = 1 - np.exp(-decoherence_rate * length)
ErrorModel(self, p, **kwargs)
return GeneratedErrorWithLength
PrefectStorageErrorModel = ErrorWithTime(PrefectError)
PrefectTransferErrorModel = ErrorWithLength(PrefectError)
PrefectOperateErrorModel = PrefectError
PrefectMeasureErrorModel = PrefectError
DephaseStorageErrorModel = ErrorWithTime(DephaseError)
DephaseTransferErrorModel = ErrorWithLength(DephaseError)
DephaseOperateErrorModel = DephaseError
DephaseMeasureErrorModel = DephaseError
DepolarStorageErrorModel = ErrorWithTime(DepolarError)
DepolarTransferErrorModel = ErrorWithLength(DepolarError)
DepolarOperateErrorModel = DepolarError
DepolarMeasureErrorModel = DepolarError
BitFlipStorageErrorModel = ErrorWithTime(BitFlipError)
BitFilpTransferErrorModel = ErrorWithLength(BitFlipError)
BitFlipOperateErrorModel = BitFlipError
BitFlipMeasureErrorModel = BitFlipError
DissipationStorageErrorModel = ErrorWithTime(DissipationError)
DissipationTransferErrorModel = ErrorWithLength(DissipationError)
DissipationOperateErrorModel = DissipationError
DissipationMeasureErrorModel = DissipationError