Quantum Computers || How it is faster than the Classical Ones? ||

Quantum Computer is the next big revolution in the field of Solving Complex Problems by Computers. Here in this post, we will look at how Quantum Computers is the next big thing. But first, we look at why we need Quantum Computers? For that we now brief the Classical Computers used by us today. The computer, mobile phones, etc we use today are classical computers which rely on Binary Bits 0 and 1. Any things you do on your computer like opening a file, doing some mathematics, watching a video, etc. Every Instruction of yours in converted into a series of 0’s and 1’s which our computers understand and respond to us. These Classical Computers can do many things like we mentioned above, in addition, it can create some games and Virtual environment to interact with. Well, if they can do such tasks then what is the need for Quantum Computers?

Yes, Classical Computers are good at doing these classical tasks. But when it comes to “parallelism” they fail or take years to compute results. Let's take an example of parallelism. Consider you have a table around which 10 people are sitting on the chairs. If I ask you what’s the best possible way to make those 10 people sit on the chair? Definitely, you would have to look at all possible arrangement and that is 10!(factorial). which is a big number and If I increase the number 10 to more bigger number our classical computers will fail badly here. So, in short, our computers are not good at exponential scaling and here comes the magic “Quantum Computers”.

Another reason we need Quantum Computers is that of Moore's law. It states that no of transistors in Chip will double in every 18 months. We now have 10nm chip technology and heading towards 7nm technology. Maybe then in 4-5 years transistors technology will be measured in atomic size which will actually fail the sole motive of transistors. Transistors basically allow or block electrons and if this size reduces down to atom then electrons can easily transport by the phenomenon called quantum teleportation. Here we look at quantum computers as a solution.

What is Quantum Computing?

Here we use properties of quantum physics into computing problems. In quantum computers, we use quantum bits or in short qubits. What are they? Binary bits can be 0 or 1 at a time but qubits are 0 and 1 simultaneously. Well,  thinks of bits as a bar magnet having a north and south pole then qubits are a sphere that can take any value from north to south or any value between them at a time. And this property is called superposition.

Superposition in quantum computing makes it extremely faster. The superposition of qubits is what gives quantum computers “parallelism”. So, it can do millions of computations at the same time. Let's take an example. Suppose you have to check a 3-bit password for a computer. 2^3 = 8. We have 8 possible states then, in which one of them is correct. Our classical computers will take each of the combination as a different state but due to superpositioning in quantum computers, it takes all possible states as one and feeds it at once and thereby making it faster.

Quantum computers also take another property of quantum physics i.e entanglement. This applies to more than one qubit. In entanglement two qubits are attached to each other and the second one inherits the properties of the first one. So, if left alone an atom will spin in all directions. The instant first atom chooses one spin the second one chooses the opposite spin. And this is helpful as we don’t even have to look at the qubits to compute its value. So, this two property make quantum computers extremely special.

Two basic things required to make quantum computers are extreme cold and powerful magnetic field. There are some models of quantum computers used today and they run at less than 0 K(Kelvin) which is achievable by providing an extreme refrigerating power.

After reading all this you might think that Quantum computers can be a replacement for Classical computers in the near future. This is wrong as Quantum computers cannot be fast always. Like Watching a video or opening a file or playing a game will not offer a great speed as these things depend upon the technology of memory used. For eg. Booting windows from HDD takes longer than booting it from SSD. Therefore, Quantum Computers is the next big thing but it cannot replace Classical ones.

At last, I would like to talk about the threats. We use greatest encryption techniques to protect our data. But all these have been made from Classical computers. Brute force algorithm takes millions of years to crack a good code. But Quantum computers can break this code within hours by even using Brute force. So, security is a great point of concern.

I hope this Information helps. Finally, Thank you.