Quantum Teleportation

In this example we will showcase how to use Qrisps quantum network module to realize a quantum teleportation.

For this, we first create a Server - this server will keep track of the participants and simulate the state of the network. Subsequently, we connect two clients

>>> from qrisp.quantum_network import *
>>> qns = QuantumNetworkServer(socket_ip = "127.0.0.1", background = True)
>>> qns.start()
>>> alice = QuantumNetworkClient("alice", socket_ip = "127.0.0.1")
>>> bob = QuantumNetworkClient("bob", socket_ip = "127.0.0.1")

We now define the functions for executing the teleportation algorithm:

 #Define Bell-Pair function
 def share_bell_pair(recipient_0, recipient_1):

     #Create Bell-Pair distribution client
     import random
     client_name = "bell_pair_distributor_" + str(random.randint(0, int(1E6)))
     telamon = QuantumNetworkClient(client_name, recipient_0.socket_ip)

     #Create Bell-pair QuantumCircuit
     bell_pair_qc = QuantumCircuit(2)

     bell_pair_qc.h(0)
     bell_pair_qc.cx(0,1)

     #Run it
     telamon.run(bell_pair_qc)

     #Distribute the qubits
     telamon.send_qubits(recipient_0.name, [bell_pair_qc.qubits[0]], "")
     telamon.send_qubits(recipient_1.name, [bell_pair_qc.qubits[1]], "")


     messages_0 = recipient_0.inbox()
     messages_1 = recipient_1.inbox()

     #Retrieve Qubit objects

     qubit_0 = messages_0[-1][0][0]
     qubit_1 = messages_1[-1][0][0]

     return qubit_0, qubit_1


#Define quantum teleportation function
 def teleport_qubit(alice, bob, teleported_qubit):

     #Share Bell-Pair
     bell_pair_0, bell_pair_1 = share_bell_pair(alice, bob)

     #Get the updated circuit for alice (now contains one half of the bell-pair)
     alice_qc = alice.get_clear_qc()

     #Perform Alice's steps of the quantum teleportation protocol
     alice_qc.cx(teleported_qubit, bell_pair_0)
     alice_qc.h(teleported_qubit)
     alice_qc.measure(bell_pair_0)
     alice_qc.measure(teleported_qubit)

     #Execute the circuit
     alice_res = alice.run(alice_qc)

     #Perform Bob's steps of the quantum teleportation protocol
     bob_qc = bob.get_clear_qc()
     #The information about the outcome alice_res is transfered via a classical channel
     if list(alice_res.keys())[0][1] == "1":
         bob_qc.x(bell_pair_1)

     if list(alice_res.keys())[0][0] == "1":
         bob_qc.z(bell_pair_1)

     bob.run(bob_qc)

     return bell_pair_1

Evaluate the defined functions:

>>> alice.request_qubits(1)

Get clear circuit for alice

>>> alice_qc = alice.get_clear_qc()

Apply some arbitrary transformation (the resulting state is teleported to bob)

>>> alice_qc.h(0)
>>> alice.run(alice_qc)
>>> received_qubit = teleport_qubit(alice, bob, alice_qc.qubits[0])
>>> bob_qc = bob.get_clear_qc()

Measure the teleported qubit

>>> bob_qc.measure(received_qubit)
>>> print(bob.run(bob_qc))
{'1': 1}

Not that quantum network simulations are always performed by the single shot simulator. To get a probability distribution of the measurement outcomes of the teleported qubit, we would have to run the above script multiple times.