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103 lines
3.3 KiB
Python
103 lines
3.3 KiB
Python
"""
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Build the superdense coding protocol. This quantum
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circuit can send two classical bits using one quantum
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bit. This circuit is designed using the Qiskit
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framework. This experiment run in IBM Q simulator
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with 1000 shots.
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.
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References:
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https://qiskit.org/textbook/ch-algorithms/superdense-coding.html
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https://en.wikipedia.org/wiki/Superdense_coding
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"""
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import math
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import qiskit
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from qiskit import Aer, ClassicalRegister, QuantumCircuit, QuantumRegister, execute
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def superdense_coding(bit_1: int = 1, bit_2: int = 1) -> qiskit.result.counts.Counts:
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"""
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The input refer to the classical message
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that you wants to send. {'00','01','10','11'}
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result for default values: {11: 1000}
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┌───┐ ┌───┐
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qr_0: ─────┤ X ├──────────┤ X ├─────
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┌───┐└─┬─┘┌───┐┌───┐└─┬─┘┌───┐
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qr_1: ┤ H ├──■──┤ X ├┤ Z ├──■──┤ H ├
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└───┘ └───┘└───┘ └───┘
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cr: 2/══════════════════════════════
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Args:
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bit_1: bit 1 of classical information to send.
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bit_2: bit 2 of classical information to send.
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Returns:
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qiskit.result.counts.Counts: counts of send state.
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>>> superdense_coding(0,0)
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{'00': 1000}
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>>> superdense_coding(0,1)
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{'01': 1000}
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>>> superdense_coding(-1,0)
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Traceback (most recent call last):
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...
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ValueError: inputs must be positive.
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>>> superdense_coding(1,'j')
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Traceback (most recent call last):
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...
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TypeError: inputs must be integers.
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>>> superdense_coding(1,0.5)
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Traceback (most recent call last):
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...
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ValueError: inputs must be exact integers.
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>>> superdense_coding(2,1)
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Traceback (most recent call last):
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...
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ValueError: inputs must be less or equal to 1.
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"""
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if isinstance(bit_1, str) or isinstance(bit_2, str):
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raise TypeError("inputs must be integers.")
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if (bit_1 < 0) or (bit_2 < 0):
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raise ValueError("inputs must be positive.")
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if (math.floor(bit_1) != bit_1) or (math.floor(bit_2) != bit_2):
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raise ValueError("inputs must be exact integers.")
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if (bit_1 > 1) or (bit_2 > 1):
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raise ValueError("inputs must be less or equal to 1.")
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# build registers
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qr = QuantumRegister(2, "qr")
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cr = ClassicalRegister(2, "cr")
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quantum_circuit = QuantumCircuit(qr, cr)
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# entanglement the qubits
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quantum_circuit.h(1)
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quantum_circuit.cx(1, 0)
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# send the information
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c_information = str(bit_1) + str(bit_2)
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if c_information == "11":
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quantum_circuit.x(1)
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quantum_circuit.z(1)
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elif c_information == "10":
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quantum_circuit.z(1)
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elif c_information == "01":
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quantum_circuit.x(1)
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else:
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quantum_circuit.i(1)
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# unentangled the circuit
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quantum_circuit.cx(1, 0)
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quantum_circuit.h(1)
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# measure the circuit
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quantum_circuit.measure(qr, cr)
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backend = Aer.get_backend("aer_simulator")
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job = execute(quantum_circuit, backend, shots=1000)
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return job.result().get_counts(quantum_circuit)
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if __name__ == "__main__":
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print(f"Counts for classical state send: {superdense_coding(1,1)}")
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