# How do quantum gates work on qubits in the physical world?

How do quantum gates work on qubits in the physical world?

What are different ways through which qubits can be manipulated in the physical world?

For example, by analogy a classical NOT gate uses electric volts as signals to change the state of the input bit to a (classical) NOT gate.

Accordingly, how would one implement an $$X$$ gate acting on a qubit?