Add Qiskit Quantum NOT Gate Example Code (#3255)

* Add Qiskit Quantum NOT Gate Example Code

* Address Review Comments
Signed-off-by: NAbhishek Jaisingh <abhi2254015@gmail.com>

quantum/not_gate.py

+#!/usr/bin/env python3
+"""
+Build a simple bare-minimum quantum circuit that starts with a single 
+qubit (by default, in state 0) and inverts it. Run the experiment 1000 
+times and print the total count of the states finally observed.
+Qiskit Docs: https://qiskit.org/documentation/getting_started.html
+"""
+
+import qiskit as q
+
+
+def single_qubit_measure(qubits: int, classical_bits: int) -> q.result.counts.Counts:
+    """
+    >>> single_qubit_measure(1, 1)
+    {'11': 1000}
+    """
+    # Use Aer's qasm_simulator
+    simulator = q.Aer.get_backend('qasm_simulator')
+
+    # Create a Quantum Circuit acting on the q register
+    circuit = q.QuantumCircuit(qubits, classical_bits)
+
+    # Apply X (NOT) Gate to Qubits 0 & 1
+    circuit.x(0)
+    circuit.x(1)
+
+    # Map the quantum measurement to the classical bits
+    circuit.measure([0, 1], [0, 1])
+
+    # Execute the circuit on the qasm simulator
+    job = q.execute(circuit, simulator, shots=1000)
+
+    # Return the histogram data of the results of the experiment.
+    return job.result().get_counts(circuit)
+
+
+if __name__ == '__main__':
+    counts = single_qubit_measure(2, 2)
+    print(f'Total count for various states are: {counts}')