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Quantum gate simulator

blueqat

A quantum computing SDK

Install

```git clone https://github.com/Blueqat/Blueqat
cd Blueqat
pip3 install -e .
```

or

```pip3 install blueqat
```

Circuit

```from blueqat import Circuit
import math

#number of qubit is not specified
c = Circuit()

#if you want to specified the number of qubit
c = Circuit(3) #3qubits
```

Method Chain

```# write as chain
Circuit().h[0].x[0].z[0]

# write in separately
c = Circuit().h[0]
c.x[0].z[0]
```

Slice

```Circuit().z[1:3] # Zgate on 1,2
Circuit().x[:3] # Xgate on (0, 1, 2)
Circuit().h[:] # Hgate on all qubits
Circuit().x[1, 2] # 1qubit gate with comma
```

Rotation Gate

```Circuit().rz(math.pi / 4)[0]
```

Measurement

```Circuit().m[0]
```

Run()

```Circuit().h[0].cx[0,1].run()
```

Run(shots=n)

```c = Circuit().h[0].cx[0,1].m[:]
c.run(shots=100) # => Counter({'00': 48, '11': 52}) (random value.)
```

Hamiltonian

```from blueqat.pauli import *

hamiltonian1 = (1.23 * Z[0] + 4.56 * X[1] * Z[2]) ** 2
hamiltonian2 = (2.46 * Y[0] + 5.55 * Z[1] * X[2] * X[1]) ** 2
hamiltonian = hamiltonian1 + hamiltonian2
print(hamiltonian)
```

simplify the hamiltonian

```hamiltonian = hamiltonian.simplify()
print(hamiltonian)
```

VQE

```from blueqat import vqe
from blueqat.pauli import qubo_bit as q

hamiltonian = -3*q(0)-3*q(1)-3*q(2)-3*q(3)-3*q(4)+2*q(0)*q(1)+2*q(0)*q(2)+2*q(0)*q(3)+2*q(0)*q(4)+2*q(1)*q(2)+2*q(1)*q(3)+2*q(1)*q(4)+2*q(2)*q(3)+2*q(2)*q(4)+2*q(3)*q(4)
step = 2

result = vqe.Vqe(vqe.QaoaAnsatz(hamiltonian, step)).run()
print(result.most_common(12))
```

If you want to create an ising model hamiltonian use Z(x) instead of q(x) in the equation

```hamiltonian = Z(0)-3*Z(1)+2*Z(0)*Z(1)+2*Z(0)*Z(2)
```

Blueqat to Qiskit

```qiskit.register(APItoken)
sampler = blueqat.vqe.get_qiskit_sampler(backend="backend name")
result = blueqat.vqe.Vqe(QaoaAnsatz(...), sampler=sampler).run(verbose=True)
```

Blueqat to QASM

```Circuit.to_qasm()

#OPENQASM 2.0;
#include "qelib1.inc";
#qreg q[1];
#creg c[1];
#h q[0];
```

Example

2-qubit Grover

```from blueqat import Circuit
c = Circuit().h[:2].cz[0,1].h[:].x[:].cz[0,1].x[:].h[:].m[:]
print(c.run(shots=1))
```

Maxcut QAOA

```from blueqat import vqe, pauli
edges = [(0, 1), (1, 2), (2, 3), (3, 0), (1, 3), (0, 2), (4, 0), (4, 3)]
ansatz = vqe.QaoaAnsatz(sum([pauli.Z(i) * pauli.Z(j) for i, j in edges]), 1)
result = vqe.Vqe(ansatz).run()
print(
"""   {4}
/ \\
{0}---{3}
| x |
{1}---{2}""".format(*result.most_common()[0][0]))
```

Annealing-2 (old)

```from blueqat import opt
a = opt.opt()
a.qubo = opt.sel(3,1) #creating QUBO matrix
result = a.sa(shots=100,sampler="fast")
opt.counter(result)

Counter({'010': 29, '100': 34, '001': 37})
```

Author

Takumi Kato (MDR), Yuichiro Minato (MDR), Yuma Murata (D Slit Technologies), Satoshi Takezawa (TerraSky)