# All you need to know about Quantum Computing

Quantum Computing studies theoretical computation systems that make direct use of quantum-mechanical phenomena, such as superposition and entanglement, to perform operations on data.

Quantum Computer is a computer that uses quantum states of subatomic particles to store information.

## History

A computer is a very complex system. It started its journey far before as various computing devices. There were a number of inventions with a vision of increasing computing speed that all together lead to the foundation of modern computation. It started with Abacus, and then the evolution began with Abacus to Napier’s bones, to Pascaline, to Punched Card System, to Tabulator, to the Digital Era where Binary System made its entry into the computer world. with Binary system computer evolved from using Vacuum tubes to valves to Transistors.

## Classical Computers

Silicon chips are used in classical computers to perform the computation. According to Moore’s law number of components on a silicon chip doubles every 18 months to 2 years. This law has been going now for about 4 decades. If we have a look at where we are at the moment the smallest feature size in the transistor is the size of 5000 times smaller than the width of a human hair. In one silicon chip, there are three billion transistors. Now imagine the size of the components on the transistors.

If observe Moore’s law and compare it with the present size of transistor then in about 2020 to 2030 the size of the transistor will be equal to the size of an atom. It is very difficult to imagine if we could reduce the size of the transistor after that.

With this many of the people predicted that it would be the end of Moore’s law. But in reality it’s the start of something new, we are transitioning to quantum mechanics. If we control quantum physics. We could build computers in the quantum regime. That is predicted to have exponential speedup over the classical Computers.

## Quantum Computer

A classical computer uses classical bits, which 0 or 1 to perform an operation. A Quantum Computer uses quantum bits or qubits to perform an operation, and they can be both 0 and 1 at the same time. And it is this which gives a quantum computer its computing power. There are a number of physical objects that can be used as qubits. A single photon, a nucleus or an electron. This is what happens when the number of qubits is increased in quantum computing.

- If we add one qubit we can be in two possible states at the same time.
- If we add another qubit then with two qubits we can be in four possible states at the same time.
- With three qubits we can be in eight possible states at the same time.

Every time we add a qubit to a quantum computer we double the computational power. So it’s been predicted that with the computer having just 30 qubits, It can be more powerful than that of the world’s most powerful super computer. If a computer has 300 qubits then its computational power would be more powerful than all computers in the world connected together.

The concept of Quantum Computing can speed up computation beyond the imagination.

Also, check Computer Security Threats

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