GQuantum(Grace Quantum Computer Simulator) is an open-source quantum computer simulator with least dependent APIs. It simulates arbitrary quantum circuits with at most 31 qubits. (本项目说明包含中文版 ，请往下翻。)
This library is distributed on PyPI and can be installed using pip:
$ pip install gquantumThe basic element in quantum computing is qubit. You can initialize several qubits with the class Qubit() in GQuantum:
import gquantum as gq
qu = gq.Qubit(2)Similar to logic gates in traditional computer, quantum gates are used to manipulate the state of qubit:
qu.h(0)
qu.cnot(0, 1)The H gate changed the first qubit from state |0> to superposition between |0> and |1>. The CNOT gate entangled the first qubit with the second qubit.
The function measure() is used to observe the state of qubit:
print(qu.measure(0))
print(qu.measure(1))Because these two qubits above are entangled, the outputs of measurements should be both |0> or |1>. To learn more, please check the API Document
We ran 50 random quantum gates with Intel(R) Xeon(R) Gold 5118 CPU. And we got average time per gate:
| Qubits Number | Average Time(s) | RAM Required(GB) |
|---|---|---|
| 31 | 35.3 | 40.9 |
| 30 | 16.2 | 20.2 |
| 29 | 8.7 | 10.2 |
Notice that the number of quantum gates executed in a practical quantum computer typically does not surpass 100 times the number of qubits in the sysytem. Otherwise the noise gonna ruin the system. Thus to practically simulate a 31 qubits quantum system, less than 3100 quantum gates should be executed. These quantum gates will spend less than 30 hours, which is acceptable by most research situation.
GQuantum(Grace Quantum Computer Simulator)是轻量级开源量子计算机模拟器。它能模拟最多31个量子位的所有量子线路。
GQuantum的安装基于 PyPI 请运行pip命令:
$ pip install gquantum量子计算的最基本元素是量子位。你可以使用GQuantum中的Qubit()类初始化多个量子位:
import gquantum as gq
qu = gq.Qubit(2)同传统计算机中逻辑门作用于比特类似，量子门用来操纵量子位:
qu.h(0)
qu.cnot(0, 1)H 门将第一个量子位从 |0> 状态变换到 |0> 与 |1> 之间的叠加态。 CNOT 建立了第一个量子位与第二个量子位的量子纠缠。
measure() 函数用于测量单个量子位的观测值:
print(qu.measure(0))
print(qu.measure(1))由于这两个量子位处于纠缠状态，当测量第一个量子位时第二个量子位跟着坍缩。所以两个量子位测量结果将同时是 |0> 或者 |1>。 更多信息请查看API 文档。
我们在 Intel(R) Xeon(R) Gold 5118 CPU 跑了50组随机量门。然后取平均得到单个量子门的运行时间:
| 量子位个数 | 单个量子门运行时间(s) | 最低需占用内存(GB) |
|---|---|---|
| 31 | 35.3 | 40.9 |
| 30 | 16.2 | 20.2 |
| 29 | 8.7 | 10.2 |
注意在真实的量子计算机中，连续作用量子门的个数一般不会超过量子位的一百倍。否则产生的物理干扰将严重影响系统。所以在真正的31位量子计算程序中，量子门一般少于3100个。GQuantum将在30小时内运行完所有的量子门，所以GQuantum能在可接受的范围内模拟几乎所有31位量子计算程序。