Computing is the use of a computer to manage, process the information to perform any activity.

Quantum computing is a type of computer technology(developed or under development) that is based on the principles of quantum theory.

Quantum theory is a subject based on the concept of energy and matter and mainly on the motion and interaction of the subatomic particles.

## Quantum computing Vs. Classical computing

Classical computing is the most widely used type of computing as of today. It uses bits(either 0 or 1). Let us consider 3-bits, we would have eight possibilities namely 000,001,010,011,100,101,110,111. A basic computer with one CPU can analyze one word of data i.e., any one of the eight possibilities at a time. The CPU has to analyze the eight possibilities and give us the desired output. In this way, we can calculate the data from Gigabytes to Petabytes depending on the CPU. if we want to analyze more than one possibility at a time, we need to use more than one CPU. This type of processing is called multiprocessing.

Quantum computing does not use bits 0 and 1. It rather uses what we call "Qubits". As we have understood, a bit stays at either 0 or 1 depending on the DC levels. Whereas, a qubit is a coherent superposition of both. The superposition here means that the bit exists partly in both 0 and 1. A CPU can analyze one word at a time whereas a QPU(Quantum Processing Unit) can analyze many possibilities at the same time.

## Quantum computing explained:

Quantum computing is based on the two concepts Quantum Superposition and Quantum Entanglement. As we have learned about Quantum Superposition, let's get to know about Quantum Entanglement.

### What is Quantum Entanglement?

Quantum entanglement is a phenomenon in Quantum Mechanics in which the quantum states are described with reference to each other even though they are spatially separated. This means that the effect on one affects the other state also. For example, if we consider the spin of one state to be clockwise, the other would be counterclockwise.

## Why Quantum Computing?

Quantum computers calculate exponential amounts of data as they are based on the probability of the state of the object even before it is measured instead of 1's and 0's.

## How does Quantum computer work?

As we have discussed, we have the concept of qubit here. A functional quantum computer holds the object in the superposition state for a long time to carry out various operations and processes. Here comes the interesting part, we cannot hold for long enough due to the concept of decoherence where the qubit gets converted into a normal bit when it meets with the measured system.

## Applications of Quantum Computing

- Molecular Modeling or Quantum chemistry
- Cryptography
- Artificial Intelligence
- Financial Modeling
- Particle Physics
- Aerospace Physics
- Quantum Simulation