Quantum Computing is a fascinating field that is consistently evolving. It has entirely different principles and operation mechanisms as compared to classical computing. One such inherent concept is Quantum Gates which is the building block of Quantum Computing just like Logic Gates are for classical computing.
Quantum gates, an analogy to classical logic gates in computing, behave as universal operators. They manipulate entry quantum states into certain output quantum states as directed. The uniqueness of these quantum gates lies in the fact they perform 'reversible' transformations, keeping the Total Quantum Information constant, a key aspect of Quantum Physics.
Let's discuss some of the single qubit quantum gates which are frequently used in quantum computing.
# Python code using Qiskit to demonstrate basic quantum gates from qiskit import QuantumCircuit, transpile, assemble, Aer, execute from qiskit.visualization import plot_bloch_multivector, plot_histogram ## Pauli-X Gate # It flips the state |0> to |1> and vice versa qc = QuantumCircuit(1) qc.x(0) qc.draw('mpl') ## Hadamard Gate # Converts |0> state to |+> = (1/sqrt(2))(|0> + |1>) state and |1> state to |-> = (1/sqrt(2))(|0> - |1>) state qc = QuantumCircuit(1) qc.h(0) qc.draw('mpl') ## Phase flip (Z) gate # Multiplies the state |1> by a phase factor of -1 (leaves |0> unchanged) qc = QuantumCircuit(1) qc.z(0) qc.draw('mpl')
It works like the NOT gate for quantum bits (or qubits). The Pauli-X gate transforms the state |0> to |1> and vice versa.
The Hadamard gate is a fundamental quantum gate. It allows us to move away from the computational basis states |0> and |1> and create superpositions. It transforms the basis state |0> to (|0>+|1>) and the basis state |1> to (|0>-|1>).
The Phase flip or Z gate flips the sign (phase) of the state |1> but leaves |0> unchanged.
These are the basic building blocks of quantum computing that can be used to create more complex operations and circuits.
Please note - to run the above code you need to have IBM's Qiskit python library installed. You can do this by running !pip install qiskit.
Stay tuned till next time when we dive into more of such interesting Quantum Computing concepts!