quantumteleport.py

import qiskit as qk
from qiskit import ClassicalRegister, QuantumRegister, QuantumCircuit
from qiskit import execute, Aer
from qiskit import IBMQ
from qiskit.visualization import plot_histogram
import matplotlib

secret_unitary = "hz"
# simple function that applies a series of unitary gates from a given string
def apply_secret_unitary(secret_unitary, qubit, quantum_circuit, dagger):
    functionmap = {
                    'x':quantum_circuit.x,
                    'y':quantum_circuit.y,
                    'z':quantum_circuit.z,
                    'h':quantum_circuit.h,                    
                    't':quantum_circuit.t,                    
    }
    if dagger: functionmap['t'] = quantum_circuit.tdg
    
    if dagger:
        [functionmap[unitary](qubit) for unitary in secret_unitary]
    else:
        [functionmap[unitary](qubit) for unitary in secret_unitary[::-1]]

# Create the quantum circuit with 3 qubits and 3 classical bits
qc = QuantumCircuit(3, 3)
print("Original Circuit:")
print(qc)

''' Qubit ordering as follows (classical registers will just contain measured values of the corresponding qubits):
q[0]: qubit to be teleported (Alice's first qubit. It was given to her after the application of a secret unitary 
      which she doesn't know)
q[1]: Alice's second qubit
q[2]: Bob's qubit, which will be the destination for the teleportation
'''

# Apply the secret unitary that we are using to generate the state to teleport. You can change it to any unitary
apply_secret_unitary(secret_unitary, qc.qubits[0], qc, dagger = 0)
qc.barrier()
# Next, generate the entangled pair between Alice and Bob (Remember: Hadamard followed by CX generates a Bell pair)
qc.h(1)
qc.cx(1, 2)
qc.barrier()

print("Bell circuit:")
print(qc)
# Next, apply the teleportation protocol. 
qc.cx(0, 1)
qc.h(0)
qc.measure(0, 0)
qc.measure(1, 1)
qc.cx(1, 2)
qc.cz(0, 2)
qc.barrier()

print("Teleportation protocol:")
print(qc)
'''
In principle, if the teleportation protocol worked, we have q[2] = secret_unitary|0>
As a result, we should be able to recover q[2] = |0> by applying the reverse of secret_unitary
since for a unitary u, u^dagger u = I.
'''
apply_secret_unitary(secret_unitary, qc.qubits[2], qc, dagger=1)
qc.measure(2, 2)

print("Final Circuit:")
print(qc)
backend = Aer.get_backend('qasm_simulator')
job_sim = execute(qc, backend, shots=1024)
sim_result = job_sim.result()

measurement_result = sim_result.get_counts(qc)
print(measurement_result)
plot_histogram(measurement_result)