-
Notifications
You must be signed in to change notification settings - Fork 2
/
superposition.py
110 lines (85 loc) · 4.13 KB
/
superposition.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
import qiskit
from qiskit import ClassicalRegister, QuantumRegister, QuantumCircuit
from qiskit import IBMQ
from configparser import RawConfigParser
type = 'real' # Run program on the simulator or real quantum machine.
def run(program, type, shots = 100):
if type == 'real':
if not run.isInit:
# Setup the API key for the real quantum computer.
parser = RawConfigParser()
parser.read('config.ini')
IBMQ.enable_account(parser.get('IBM', 'key'))
run.isInit = True
# Set the backend server.
backend = qiskit.providers.ibmq.least_busy(qiskit.IBMQ.backends(simulator=False))
# Execute the program on the quantum machine.
print("Running on", backend.name())
job = qiskit.execute(program, backend)
return job.result().get_counts()
else:
# Execute the program in the simulator.
print("Running on the simulator.")
job = qiskit.execute(program, qiskit.Aer.get_backend('qasm_simulator'), shots=shots)
return job.result().get_counts()
run.isInit = False
#
# Example 1: Measure 2 qubits in their initial state, all zeros.
#
# Setup qubits.
qr = QuantumRegister(2)
cr = ClassicalRegister(2)
program = QuantumCircuit(qr, cr);
# Measure the value of the qubits in their initial state, they should be all zeros.
program.measure(qr, cr);
# Execute the program.
print(run(program, type))
#
# Example 2: Create a Bell state (|00> + |11>), (|00> - |11>), (|01> + |10>), (|01> - |10>): Entangle 2 qubits, with the first in superposition (existing as 0 and 1 simulataneously or 50% chance of either value) and measure the results, they should be half 00 and half 11.
#
# Setup qubits.
qr = QuantumRegister(2)
cr = ClassicalRegister(2)
program = QuantumCircuit(qr, cr);
# Place the first qubit into a superposition, existing as both 0 and 1 simultaneously.
program.h(qr[0])
# Entangle the two qubits with a controlled NOT operator. If the first qubit is 1, the second qubit will be inverted. Depending on the initial qubit states, this results in the 4 Bell states (|00> + |11>), (|00> - |11>), (|01> + |10>), (|01> - |10>).
program.cx(qr[0], qr[1])
# Sender: Invert the first qubit to set it from 0 to 1 (remember, we're trying to represent 01 by manipulating only a single qubit q[0]).
# 00 I - Identity nothing to do
# 01 X - program.x(qr[0])
# 10 Z - program.z(qr[0])
# 11 XZ - program.x(qr[0]) program.z(qr[0])
program.x(qr[0])
# Measure the value of the qubits, they should be equally 00 and 11, one of the Bell states.
program.measure(qr, cr);
# Execute the program.
print(run(program, type))
#
# Example 3: Superdense coding: send two classical bits of information (01) by only manipulating a single qubit: Reverse a Bell state: Entangle 2 qubits, with the first in superposition, then reverse the steps and measure the results, they should be all zeros.
# The first qubit is owned by Alice.
# The second qubit is owned by Bob.
# Alice will modify her qubit qr[0] in order to end up representing 01 to Bob, then send her qubit to him.
# Bob will reverse the entanglement and superposition of Alice's qubit and read the results, getting 01 from the qubits (his qubit miraculously turns into a 1).
# Setup qubits.
qr = QuantumRegister(2)
cr = ClassicalRegister(2)
program = QuantumCircuit(qr, cr);
# Sender: Place the first qubit into a superposition, existing as both 0 and 1 simulateneously.
program.h(qr[0])
# Sender: Entangle the two qubits with a controlled NOT operator. If the first qubit is 1, the second qubit will be inverted, otherwise it remains the same.
program.cx(qr[0], qr[1])
# Sender: Invert the first qubit to set it from 0 to 1 (remember, we're trying to represent 01 by manipulating only a single qubit q[0]).
# 00 I - Identity nothing to do
# 01 X - program.x(qr[0])
# 10 Z - program.z(qr[0])
# 11 XZ - program.x(qr[0]) program.z(qr[0])
program.x(qr[0])
# Receiver: Repeat the controlled NOT operator, reversing the entanglement.
program.cx(qr[0], qr[1])
# Receiver: Repeat the Hadamard, reversing the superposition state.
program.h(qr[0])
# Receiver: Measure the value of the qubits, we should get back the original values.
program.measure(qr, cr);
# Execute the program.
print(run(program, type))