First of all,what is quantum physics?
Quantum physics describes behaviours of fundamental particles like atoms,electrons,photons,subatomic particles,etc. Similarly,a quantum computer is a computer which involves operation of behaviours of these fundamental particles,but in a totally different way from a regular computer. IBM,one of the world’s reputed tech giants has built a working quantum computer. It’s not just an updated version of regular computers,but uses deeper science and technology,based on quantum physics. So quantum computers can solve problems that would take infinitely deeper time on a regular computer. One key difference between regular computers and quantum computers is that regular computers uses data in the form of binary bits 0 and 1. But quantum computers relies on quantum physical phenomena,so they use data in form of quantum bits or qubits.
What is a qubit?
One may consider qubits as fundamental subatomic particles like electrons and photons. Qubits have some typical quantum properties. Thus a group of them can provide more processing power compared to exactly same number of binary bits. These properties include superposition andentanglement.
Superposition – The property of simultaneously existing in multiple states by numerous possible combinations of 1 and 0 is called superposition.Devices like precision lasers and microwave beams are used for such purposes. Quantum Computers in such state can produce a vast number of potential outcomes at the same time. Final result is taken after measuring all the qubits,causing a collapse in their quantum states to either 1 or 0.
Entanglement – Pairs of qubits,in which both members exist in a single quantum state,where changing state of one member affects the other one even if separated by long distances is known as entanglement. Unlike conventional computers,where processing power gets doubled on doubling number of bits,quantum computers shows an exponential increase in its number-crunching ability,by addition of extra qubits. Using specially designed quantum algorithms,quantum computers can speed up the calculations.
Decoherence – Quantum computers are way more prone to errors than traditional computers due to decoherence. Quantum states of qubits is very fragile. Thus their interaction causes a decay in their quantum behaviour.This phenomena is called decoherence.
Quantum Supremacy – A point where a mathematical calculation,which is beyond the reach of modern supercomputers,is performed by a supercomputer is known as quantum supremacy. Research is going on to explore new algorithms for boosting up the performance. However it is still unknown about number of qubits required to achieve this state.