Example episode

Taken from qiskit.org, licensed under Apache License 2.0

import numpy as np
from qiskit import QuantumCircuit, transpile
from qiskit.providers.aer import QasmSimulator
from qiskit.visualization import plot_histogram

Define circuit

# Use Aer's qasm_simulator
simulator = QasmSimulator()

# Create a Quantum Circuit acting on the q register
circuit = QuantumCircuit(2, 2)

# Add a H gate on qubit 0
circuit.h(0)

<qiskit.circuit.instructionset.InstructionSet at 0x162a9ac40>

# Add a CX (CNOT) gate on control qubit 0 and target qubit 1
circuit.cx(0, 1)

<qiskit.circuit.instructionset.InstructionSet at 0x162aafe80>

# Map the quantum measurement to the classical bits
circuit.measure([0,1], [0,1])

<qiskit.circuit.instructionset.InstructionSet at 0x162ab6540>

Transpile circuit and execute it

# compile the circuit down to low-level QASM instructions
# supported by the backend (not needed for simple circuits)
compiled_circuit = transpile(circuit, simulator)

# Execute the circuit on the qasm simulator
job = simulator.run(compiled_circuit, shots=1000)

# Grab results from the job
result = job.result()

# Returns counts
counts = result.get_counts(compiled_circuit)
print("\nTotal count for 00 and 11 are:",counts)

Total count for 00 and 11 are: {'00': 498, '11': 502}

Visualize results

# Draw the circuit
circuit.draw()

     ┌───┐     ┌─┐   
q_0: ┤ H ├──■──┤M├───
     └───┘┌─┴─┐└╥┘┌─┐
q_1: ─────┤ X ├─╫─┤M├
          └───┘ ║ └╥┘
c: 2/═══════════╩══╩═
                0  1 

# Plot a histogram
plot_histogram(counts)

Exercise

Some exercise

Description of exercise.

1. Do this

2. then do this

3. finally observe what happens when you do this…

Solution

Here is the solution