Quantum computers:The future computer | Quantum computing | Qubits | digital security | MessyMind

Technology has advanced a lot in the last few decades. We have switched from wired telephone to wireless mobile phone, from big fat TV to slim LCD, from one-time use rockets to reusable rockets and many more. Now its time to replace our normal computer with something superfast and more efficient. 

What if we could replace the core technology on which our normal computer works? What if we could do big scientific calculations within seconds? This would be revolutionary invention. That’s the reason why the Tech giants of the world, Google and IBM, are spending billions on the research for Quantum Computer. 

What is Quantum Computer?

Quantum Computer is not the advanced version of our normal computer. In fact, quantum computer is itself a new kind of device. Just like bulb is not the advanced version of candle, it is itself a new invention. Quantum computer works on the principles of quantum physics, which is way different than our normal physics. Quantum computer, being in its infancy, is faster than the today’s super computer. So, we can imagine how fast it would be when it is fully developed. What makes quantum computer different? The main difference is that Quantum computer uses qubits whereas normal computer uses bits...

What’s the difference between bits and 
qubits?

Bits can take value of either 0 or 1. The 0 bit means low voltage or no voltage. Whereas 1 means high voltage. On the other hand, Qubits can be in 0 and 1 state simultaneously, this property is referred as Coherence. 

Bits represents discrete set (either 0 or 1) whereas qubits represent continuous set (0 to 1). You can imagine qubits as mixture of 2 liquids.

Until measured qubits exist in intermediate state 0 or 1. Being present in the intermediate state makes qubits faster. How do it make qubits faster? Before understanding this, we need to clear concept about superposition and entanglement.

i. Superposition 

It is the property of being present in all the possible states at the same time. Let’s make it simple. Just imagine of the coin. When you toss a coin any one of the 2 outcomes can come i.e. head or tail. When the coin is tossed and while it is in air the coin is in both the states (head as well as tail). So, in physics we can say that coin is in the superposition state of head and tail. Like for qubits it can exist in both the states (0 and 1) simultaneously. So, in physics we can say that qubit is in superposition state of 0 and 1. 

ii. Quantum Entanglement

According to quantum theory, there is no individual particle. Every particle is connected to another particle through an invisible connection, just like umbilical cord connecting mother and her child. You can imagine these particles as couples. These particles are dependent on each other, changes in any one also changes the other one. 

This concept can be understood by an example. If an electron changes its spin (the direction of rotation) from up to down then its entangled partner changes its spin from down to up. Albert Einstein called it “spooky action at a distance”.

The qubits are entangled with one another and exist in superposition state. So, changes in anyone changes the other, even if both the particles are separated by light years distance. Hence making it very fast. 

Why are quantum computers so fast? 

The 40-Qubit quantum computer is way faster than today’s super computer with 64 bits. 4-bit computer means having 16 (24) states in total out of which only one state is used at a time. Where as in quantum computers if 16 states are present, all the states are used together (or parallelly). This makes quantum computers so fast. 

Let me give you a real-life example. 

First scenario, you alone are handling the sales, marketing, HR and finance department of a company. 

Second scenario, there are 4 different people handling the sales, marketing, HR and finance department of the company and all of them working at the same time (parallelly).

In which of the above-mentioned scenarios, we can expect better and faster performance? The answer is simple, in the second scenario.

The same is true for quantum computers. All the possibilities are checked parallelly, all at a time (like 2nd scenario). On the other hand, normal computer checks all the possibilities one after another (like 1st scenario).This makes it faster than normal computers. 

What is the need of new kind of computer? 

As the time is progressing, computers are getting more efficient and faster that too without increase in its size. How is it happening? The smallest data processing unit of normal computer is the Transistor. It is like a switch. The switch can either open (1 state) or close (0 state). The computer is getting faster without the increase in its size implies that transistor is getting smaller and smaller. Today’s transistor is too small, of the size of 14 nanometer. You can compare, the transistor is 500 times smaller than our red blood cell. 

To increase the speed of the computer, transistor needs to keep decreasing in its size. But there is a limit on the size of transistor, it needs to be bigger than the size of an electron. It is because the information which flows through the transistors is basically in the form of the flow of electrons. 

That’s why we need another kind of computer, not using transistors but faster and more efficient at the same time. The alternative option is Quantum computer which works on the principle of Quantum mechanics. 

Why are quantum computers hard to build? 

There are many challenges in building a working, easy to access quantum computer. These are: -

1.The stability of qubit is very short. 

2.The quantum computer needs to be cooled down to 0 kelvin temperature, which is difficult to maintain.

3.Qubit implementation have higher error rate. So, it needs to run multiple times to minimize the error rate.

4.Quantum decoherence is one of the biggest challenges. Decoherence means that the qubit becomes bit which is capable of storing either 0 or 1 but not both at a time. 

These are few of many challenges faced by the developers of quantum computers. 

What is the use of developing quantum 
computer? 

There are many drawbacks of normal computer which can be solved by using quantum computers. The main fields where quantum computers can do wonders are: -

1. Digital security: -

The digital security in todays era is based on the algorithm (set of mathematical equations). The hackers can easily hack these algorithms. Basically, there are 2 types of keys:

a. private key (which you have and only you can operate it) 

b.public key (this is present with everybody who sends you something digitally). 

The private key is fixed and static (don’t change). But quantum computers can make the private key dynamic (changes with time). Quantum computer will keep on generating random codes so that no hacker can hack the system. Hence making it very secure.

2. Pharmaceuticals

There are varieties of drugs which are manufactured worldwide. There is a test done by stimulating the compound on computer. That means making the compound digitally before manufacturing it physically. This process is too difficult with normal computers but quantum computer can make it easy. Hence the stimulation process would become very simple and lots of effort, money and time would be saved by testing the compounds digitally.

3.Information transfer: -

Today information is transferred physically using the Radio waves. This makes the process slower, as the data needs to be transmitted physically and is less secure. The use of teleportation along with quantum computers can make the process very fast and more secure as the data needs not to be transmitted physically. You can check Quantum Teleportation for more details.

These are few of the fields where quantum computers can do wonders. 

No doubt quantum computers can do wonders. But there is also a problem. If any person with evil intention gets to use the quantum computers, then there can be many destructions as well. If quantum computers can make security better, then it can also break the security. If it can solve the big problems, it can also create many. Always there are good as well as bad sides of every discovery. What matters is how we use it…… what do you think about quantum 
computers?

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