diff --git a/quantum/superdense_coding.py b/quantum/superdense_coding.py new file mode 100644 index 000000000..c8eda3811 --- /dev/null +++ b/quantum/superdense_coding.py @@ -0,0 +1,102 @@ +""" +Build the superdense coding protocol. This quantum +circuit can send two classical bits using one quantum +bit. This circuit is designed using the Qiskit +framework. This experiment run in IBM Q simulator +with 1000 shots. +. +References: +https://qiskit.org/textbook/ch-algorithms/superdense-coding.html +https://en.wikipedia.org/wiki/Superdense_coding +""" + +import math + +import qiskit +from qiskit import Aer, ClassicalRegister, QuantumCircuit, QuantumRegister, execute + + +def superdense_coding(bit_1: int = 1, bit_2: int = 1) -> qiskit.result.counts.Counts: + """ + The input refer to the classical message + that you wants to send. {'00','01','10','11'} + result for default values: {11: 1000} + ┌───┐ ┌───┐ + qr_0: ─────┤ X ├──────────┤ X ├───── + ┌───┐└─┬─┘┌───┐┌───┐└─┬─┘┌───┐ + qr_1: ┤ H ├──■──┤ X ├┤ Z ├──■──┤ H ├ + └───┘ └───┘└───┘ └───┘ + cr: 2/══════════════════════════════ + Args: + bit_1: bit 1 of classical information to send. + bit_2: bit 2 of classical information to send. + Returns: + qiskit.result.counts.Counts: counts of send state. + >>> superdense_coding(0,0) + {'00': 1000} + >>> superdense_coding(0,1) + {'01': 1000} + >>> superdense_coding(-1,0) + Traceback (most recent call last): + ... + ValueError: inputs must be positive. + >>> superdense_coding(1,'j') + Traceback (most recent call last): + ... + TypeError: inputs must be integers. + >>> superdense_coding(1,0.5) + Traceback (most recent call last): + ... + ValueError: inputs must be exact integers. + >>> superdense_coding(2,1) + Traceback (most recent call last): + ... + ValueError: inputs must be less or equal to 1. + """ + if (type(bit_1) == str) or (type(bit_2) == str): + raise TypeError("inputs must be integers.") + if (bit_1 < 0) or (bit_2 < 0): + raise ValueError("inputs must be positive.") + if (math.floor(bit_1) != bit_1) or (math.floor(bit_2) != bit_2): + raise ValueError("inputs must be exact integers.") + if (bit_1 > 1) or (bit_2 > 1): + raise ValueError("inputs must be less or equal to 1.") + + # build registers + qr = QuantumRegister(2, "qr") + cr = ClassicalRegister(2, "cr") + + quantum_circuit = QuantumCircuit(qr, cr) + + # entanglement the qubits + quantum_circuit.h(1) + quantum_circuit.cx(1, 0) + + # send the information + c_information = str(bit_1) + str(bit_2) + + if c_information == "11": + quantum_circuit.x(1) + quantum_circuit.z(1) + elif c_information == "10": + quantum_circuit.z(1) + elif c_information == "01": + quantum_circuit.x(1) + else: + quantum_circuit.i(1) + + # unentangled the circuit + quantum_circuit.cx(1, 0) + quantum_circuit.h(1) + + # measure the circuit + quantum_circuit.measure(qr, cr) + + backend = Aer.get_backend("qasm_simulator") + job = execute(quantum_circuit, backend, shots=1000) + + return job.result().get_counts(quantum_circuit) + + +if __name__ == "__main__": + print(f"Counts for classical state send: {superdense_coding(1,1)}")