qiskitで量子もつれ その2

概要

量子もつれが、分からないので、copilotに聞いてみた。
ベルの不等式の破れを実験したい。

サンプルコード

from qiskit import QuantumCircuit
from qiskit_aer import AerSimulator
from qiskit.primitives import StatevectorSampler as Sampler

qc = QuantumCircuit(2, 2)
qc.h(0)
qc.cx(0, 1)
qc.measure([0, 1], [0, 1])
sampler = Sampler()
job = sampler.run([qc], shots = 1024)
result = job.result()
counts = result[0].data.c.get_counts()
print(f" > Counts: {counts}")

def get_probabilities(counts):
	total_shots = sum(counts.values())
	probabilities = {key: value / total_shots for key, value in counts.items()}
	return probabilities

probabilities = get_probabilities(dict(counts))

E_A0_B0 = probabilities.get('00', 0) + probabilities.get('11', 0) - probabilities.get('01', 0) - probabilities.get('10', 0)
E_A0_B1 = probabilities.get('00', 0) + probabilities.get('11', 0) - probabilities.get('01', 0) - probabilities.get('10', 0)
E_A1_B0 = probabilities.get('00', 0) + probabilities.get('11', 0) - probabilities.get('01', 0) - probabilities.get('10', 0)
E_A1_B1 = probabilities.get('00', 0) + probabilities.get('11', 0) - probabilities.get('01', 0) - probabilities.get('10', 0)


S = abs(E_A0_B0 - E_A0_B1 + E_A1_B0 + E_A1_B1)
print(f"CHSH Inequality S: {S}")

if S > 2:
	print("Bell Inequality is violated!")
else:
	print("Bell Inequality is not violated.")

実行結果

破れていない。

$ python3 test5.py
 > Counts: {'00': 511, '11': 513}
CHSH Inequality S: 2.0
Bell Inequality is not violated.

$ python3 test5.py
 > Counts: {'11': 530, '00': 494}
CHSH Inequality S: 2.0
Bell Inequality is not violated.

以上。