**What is a Quantum Computer?**

Quantum computers are nothing like the regular computers or even supercomputers. While the top Supercomputers use extensive parallelism with numerous processing units to get its super speed, the Quantum computers work with the physics of quantum mechanics at its core.

A quantum computer is built atom by atom. Now, quantum mechanics in itself is one of the most dreaded topics in physics, so it is no surprise that the quantum computer bears the same traits as well.

**How Does Quantum Computing Work?**

The quantum computers use atoms (quanta) as its physical system. Unlike in regular computing where the information is carried in either 0 or 1 bit, the quantum mechanics allows an atom to be in both 0 and 1 state simultaneously. This bit of data is called a qubit. ( Don’t hold your head just yet!)

So, as per the theory, if there are equal number of qubits and the regular bits, then the qubits will hold twice the information, i.e. if there are n qubits in the supercomputer, then it will have 2^n different states. So experimentally, it can hold more information as compared to regular digital bits thereby increasing the speed of the system exponentially.

In theory, the quantum phenomenon seems mind blowing but actually building one is equally painstaking. The qubits are dynamic and are only the probabilistic superposition of all of their states. So, the accurate measurement is difficult and requires complex algorithms such as Shor’s algorithm.

**What are the Challenges To Quantum Computing?**

One of the biggest challenges is to remove quantum decoherence. Decoherence in a layman’s language could be understood as the loss of information to the environment. The decoherence of the qubits occurs when the system interacts with the surrounding in a thermodynamically irreversible manner.

So, the system needs to be carefully isolated. Freezing the qubits is one of the ways to prevent decoherence.

**Past And Present Of Quantum Computing:**

The concept of Quantum computing was laid down in the 1980s, but major progress started only two decades later. In 2001, researchers demonstrated Shor’s algorithm to factor 15 using a 7-qubit NMR computer. After that, developments in the field of quantum computing operating system and expansion in the qubit numbers were focussed.

As of today, many private players have entered into the competition to build a quantum computer, that would actually silence the critics. D-Wave has recently claimed to break the 1000 qubits barrier record. Other tech giants such as Google and IBM are advancing to develop their own quantum computers as well.

**If It’s So Complex, Why Is Everyone After Quantum Computing?**

A fully functional quantum computer would require around a million atoms. And right now, we are at a mere thousand. But, what would happen if we reach that limit or even its half?

The complex and massive calculations for example in genome sequencing or tracking weather patterns require huge computers or supercomputers for that matter. Now with the current technology, if the amount of data that a supercomputer can handle is increased by just one digit, the system would fail and you would require an even bigger supercomputer.

Second, the modern day encryption systems are entirely based on the limitations of the regular computers. The normal computers can’t figure out the huge probabilistic analysis required to decrypt any sophisticated code. Even a supercomputer would take years decrypting the RSA cryptography, whereas with the help of Quantum computing it would be a matter of days, if not hours.

Quantum computers will lead to research that are either considered hypothetical or at a standstill. From simulating and computing the molecular scale structures to stretching far into the mysteries of Universe, we cannot even dream of the possibilities.

Quantum computing won’t be of changing your lives in day to day operations, but a quantum communication network would definitely provide a better and secure network.

Reference: Wikipedia, fossbyte

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