用 150 行 Python 代码写的量子计算模拟器

简评：让你更轻松地明白，量子计算机如何遵循线性代数计算的。

这是个 GItHub 项目，可以简单了解一下。

qusim.py 是一个多量子位的量子计算机模拟器（玩具？），用 150 行的 python 所编写。

这段代码可以让你轻松了解量子计算机如何遵循线性代数来计算的！

from QuSim import QuantumRegister

#############################################

Introduction

#############################################

Here Will Be A Few Example of Different

Quantum States / Algorithms, So You Can

Get A Feel For How The Module Works, and

Some Algorithmic Ideas

#############################################

#############################################

Quantum Measurement

#############################################

This experiment will prepare 2 states, of a

Single qubit, and of 5 qubits, and will just

Measure them

OneQubit = QuantumRegister(1) # New Quantum Register of 1 Qubit
print('One Qubit: ' + OneQubit.measure()) # Should Print 'One Qubit: 0'

FiveQubits = QuantumRegister(5) # New Quantum Register of 5 Qubits

Should Print 'Five Qubits: 00000'

print('Five Qubits: ' + FiveQubits.measure())

#############################################

Swap 2 Qubits

#############################################

Here, We Will Apply a Pauli-X Gate / NOT Gate

To the first qubit, and then after the algorithm,

it will be swapped to the second qubit.

Swap = QuantumRegister(2) # New Quantum Register of 2 qubits
Swap.applyGate('X', 1) # Apply The NOT Gate. If Measured Now, it should be 10

Start the swap algorithm

Swap.applyGate('CNOT', 1, 2)
Swap.applyGate('H', 1)
Swap.applyGate('H', 2)
Swap.applyGate('CNOT', 1, 2)
Swap.applyGate('H', 1)
Swap.applyGate('H', 2)
Swap.applyGate('CNOT', 1, 2)

End the swap algorithm

print('SWAP: |' + Swap.measure() + '>') # Measure the State, Should be 01

#############################################

Fair Coin Flip

#############################################

Shown in this 'Experiment', is a so called 'Fair Coin Flip',

Where a state will be prepared, that has an equal chance of

Flipping to Each Possible State. to do this, the Hadamard

Gate will be used.

New Quantum Register of 1 Qubit (As a coin has only 2 states)

FairCoinFlip = QuantumRegister(1)

If measured at this point, it should be |0>

Apply the hadamard gate, now theres an even chance of measuring 0 or 1

FairCoinFlip.applyGate('H', 1)

Now, the state will be measured, flipping the state to

either 0 or 1. If its 0, we will say "Heads", or if its

1, we will say "Tails"

FairCoinFlipAnswer = FairCoinFlip.measure() # Now its flipped, so we can test
if FairCoinFlipAnswer == '0':
print('FairCoinFlip: Heads')
elif FairCoinFlipAnswer == '1':
print('FairCoinFlip: Tails')

#############################################

CNOT Gate

#############################################

In this experiment, 4 states will be prepared, {00, 01, 10, 11}

And then the same CNOT Gate will be run on them,

To Show The Effects of the CNOT. The Target Qubit will be 2, and the control 1

New Quantum Register of 2 Qubits, done 4 times.

If any are measured at this time, the result will be 00

ZeroZero = QuantumRegister(2)
ZeroOne = QuantumRegister(2)
OneZero = QuantumRegister(2)
OneOne = QuantumRegister(2)

Now prepare Each Into The State Based On Their Name

ZeroZero Will be left, as thats the first state anyway

ZeroOne.applyGate('X', 2)
OneZero.applyGate('X', 1)
OneOne.applyGate('X', 1)
OneOne.applyGate('X', 2)

Now, a CNOT Will Be Applied To Each.

ZeroZero.applyGate('CNOT', 1, 2)
ZeroOne.applyGate('CNOT', 1, 2)
OneZero.applyGate('CNOT', 1, 2)
OneOne.applyGate('CNOT', 1, 2)

Print the results.

print('CNOT on 00: |' + ZeroZero.measure() + '>')
print('CNOT on 01: |' + ZeroOne.measure() + '>')
print('CNOT on 10: |' + OneZero.measure() + '>')
print('CNOT on 11: |' + OneOne.measure() + '>')

主要代码来自：corbett/QuantumComputing.

如果你对用 RUST 所写的高效、高性能的硬件量子计算模拟器有兴趣，可以点击 QCGPU 来查看更多内容。

GITHUB 地址：adamisntdead/QuSimPy