Quantum computing

What are Quantum computers?

A Quantum computer harnesses the mystical phenomena of quantum mechanics such as superposition and entanglement to gain a huge leap in processing power which can surpass the processing limit for present-day classical supercomputers.

    The difference between Quantum computer to classical computers 

    A classical computer and a quantum computer are fundamentally different from each other because a classical computer performs operations using the "classical bits" which can be either at a particular instant of time. A quantum computer performs operations using "qubits" which can be 0 and 1 both at a particular instant of time.

    How quantum computers work

    Qubits 

    Unlike a polished bit, a qubit can be 0 or 1 both at the same instant of time. This special property gives the quantum computer an upper edge in storing data and performing calculations over classical computers. Several physical objects can be used as qubits example photon, electron, neutron e.t.c. as these objects show quantum nature. In the present scenario, scientists are using the outermost electron of phosphorous as qubits.

    Qubits

    How does Qubit work?

    The essence of how a qubit works and how the quantum computer is faster than classical computers can be understood if we take two or qubits. Due to its charge, all electron have their magnetic field and act like a bar magnet aligned according to their magnet field, this is called spin. Now if we give just enough energy to this electron to flip its alignment against the magnetic field, it would give rise to an opposite spin. These two spins can be referred to as 0 and 1. It would seem to be similar to a classical bit, but there is a catch here that the electron( qubit) can be 0 and 1 at the same time when we are about to measure the spin.

        Suppose we take 2 qubits then the possible states are 01,00,10,11, as we can see there are 4 states possible at the same time so they can store 4 bits of information, unlike the classical bit which would store only 2 bits of information. A similar trend can be seen in the case of 3 qubits which can store 8 bits of information, on the contrary, the classical bit will store only 3 bits of information. So it can be generalized as n qubits store 2^n bits of information whereas n classical bits store only n bits of storage.

    Can quantum computers replace classical computers?

    Quantum computer is not universally faster than the classical computer they are only faster in the sense of the high demanding task. They work faster just because it can reduce the number of operations to reach a result by a significant no. of times. The improvement is not in the speed of individual operations. They are only fast in the case of a particular type of calculation and algorithm, they cannot be used in our day-to-day life such as video streaming surfing the net, etc. So in conclusion quantum computers are surely not the replacement for classical computers.