quantum computers explained simply (complete guide)

  

Quantum computers, this a term which you probably have heard at some point, even if you are not much into technology

this computing is probably the future of mankind

In this article, we will be covering the following topics

Do quantum computers exist?

yes they exist, but they are not very powerful

 Quantum computers are now a thing of reality, but the existing quantum computers are at the very initial phase of development, the current quantum computers are the ones born right after theory 

Leading technology companies such as IBM and Google have been constantly researching on quantum computing and now they have successfully developed quantum computers which are able to solve certain problems

At the end of this article we will also link you to the IBM’s quantum com[puter experience, so you yourself can actually experience the technology of future

There is even a company that sells quantum computers, called D-Wave D-Wave 

quantum computers 

a computer using quantum mechanics for its working

Quantum computers are a kind of computers that can do a number of tasks all at once (see: 8 topics quantum mechanics complete beginner's guide), which a normal or classical computer will take a lot of time to do (or probably would be unable to do it)

A combination of quantum mechanics and computing is quantum computing

computing+quantum mechanics=quantum computing

these computers are basically exploiting 2 principles of quantum mechanics namely

• Quantum entanglement
• Quantum superposition

These phenomena actually scale up the computational powers of computers exponentially

People think of computers as a laptop, pc, mobile phone or a tablet, all of these including the supercomputers have a very similar basic principle of operation

Whereas quantum computers, on the other hand, have an entirely different principle of operation, which allows them to transcend the barrier of time, faced by classical computers

Quantum computers are fast at doing a number of tasks at once, so if you are thinking that exchanging your computer with a quantum computer would make your computer super fast

You are wrong

In fact, the exact opposite of this false belief is true

If we use these computers normal everyday tasks such as surfing the internet, watching movies, playing games, they will perform even slower than normal or classical computers

The reason for this is that quantum computers are able to do a number of tasks at once, not a series of tasks at once

explanation

Think of it as a task of digging an of a pit in the ground

What a quantum computer can do is-

Dig 1000 pits of about 10meters deep in 1 second

What a normal computer can do is-

Dig 1 pit of about 100 meters deep in 1 second

So this can be thought as, a quantum computer is more efficient in doing a number of tasks at once, but a classical computer can do a series of tasks i.e one task after the other

“what a quantum computer can do a normal computer can’t and what a normal computer can do a quantum computer can’t”.

because of their special abilities, these computers can do a number of tasks, some of them are

quantum computing applications

There is a lot of confusion in the minds of people about what can a quantum computer do

Some think that one can talk to aliens, some say that hacking will be a lot easier with the help of quantum computers

Some of these guesses are right and some are wrong

A quantum computer is simply a computer which is very good at doing a lot of tasks at once

With this principle in mind let’s explore what quantum computers can do

#1 read/understand a new language

new languages and secret messages may be decoded by their use

For decoding a newly discovered language, a person needs to have a good amount of knowledge of many other languages

By knowing many languages it will be possible to match the language and symbols with existing this language

but, How to simplify this time-consuming task

The answer is quantum computers

All we have to do is to feed the data of known languages in the computer

The computer will match the characters of the new language with the known languages

Whenever there will be a match or even some similarity between the new characters and the existing one the matching characters will be decoded

This is how all this can be understood simply

1. Think of matching a character with the characters of a particular known language as a small task
2. Now there a number of languages all around the world, so there are a number of small tasks to do
3. And it is now needless to say that a quantum computer is good at doing a large number of tasks at once

Thus this is an effortless task for the quantum computer

If classical computers were used in the same place, it would take even years to complete

#2 develop a cure for a new disease-

Quantum computers can help us in finding out the vaccine of a new and unknown disease

This process of finding a possible vaccine is very similar to the previous process of decoding newly discovered Language

Here we have to feed the structure of the disease-causing microorganism along with the medicines that work on similar structured disease-causing agent

The computer can analyze all these known medicines and reveal the closest possible medicine which will work

We can try this medicine and make certain required improvements to find the actual cure of the new disease

#3 traffic control -

Quantum computers can help us by telling us the shortest path to a given destination

present computers can also do this, but quantum computers can help us in saving time by fastening up the process

All we need to do is feed all the possible paths to a certain destination program the computer to find the optimal path

 

#4 finding the deepest point

with the use of quantum tunneling the deepest point in a particular area can be found out

These computers can do interesting things by the use of the quantum phenomenon of tunneling

By quantum tunneling, a particle can bypass a barrier without actually crossing the barrier, but by going right through the barrier

So if we wish to find the lowest point in a particular terrain, an electron can pass all the barriers and reach the lowest point

The terrain as seen from the eyes of an electron will look like a plain surface with a single hole where an electron will go and fall and that in this case is our required answer

#5 Break and improve security-

This might be hard to digest at once, but it’s true

Quantum computers can break the security that modern communication systems are using (encryption), while at the same time they can improve the security with the techniques modern systems are not using

To understand how all this makes sense, let’s understand how encryption works

Suppose your computer has to communicate with a server in a way that no one sees the message that you send to the server and the messages that your server sends to you, except you and the server itself

To design such a process we have to need to keep in mind the following

• exchangeable messages should be scrambled(encrypted)
• The method of decoding scrambled messages must be known only to the server and you

This is how it’s done

Consider there are 2 keys

• The public key (can only lock the messages, and is present with everyone)
  The private key (can only unlock a message locked by corresponding private key)
• The public key is only used to lock or scramble the messages, and the private key is only used to unlock the messages
• The public and private keys come in pairs i.e the corresponding private key can only unlock the messages locked by the public key

Here’s the complete process that happens during communication

step-1 server sends a scrambled message

suppose server has to send you a message, so it locks it with a public key(whose corresponding private key is only present with the server) and sends the locked message

Even if someone finds the scrambled message in between, it would make no sense

but, when you receive the message, you would need a corresponding private key which is only present with the server

step-2 generate your own private key

You now generate your own private key

lock it with the server’s public key and send it to the server

The server has the private key to unlock your message that has your new private key

hence, both of you have a common private key to unlock or unscramble the messages

This is how modern-day encryption works

braking the security

The flaw in this encryption system is that since everyone has access to the public key (by which the messages can only be locked)

Given enough time they can figure out the corresponding private key

But the time required by classical computers to do this would be so long that there would be a new private key in use by then (generated by you)

But, quantum computers can help us here

Figuring out a private key of corresponding public key involves trying out a number of combinations

And as said above doing a number of small tasks is quite an easy task to do for a quantum computer

Thus someone with the knowledge of quantum computing can certainly bypass this security used in communication and read messages in between

Improving security (quantum cryptography)

quantum cryptography can enhance the security to a level where it would be nearly impossible for anyone to evesedrop

To understand how quantum computers help us in improving security, we need to see what are q bits

Q bits are a basic unit of information, that is processed by a quantum computer

Q bits can be thought as bits of information

In a classical computer, information is processed as bits which can be 1 or 0 at a time, but q bits can be 1 and 0 both at the same time (quantum superposition

But, here’s the catch

Q bits are 1 and 0 both but, they collapse to either of the values when they are measured

Thus measuring a q bit will yield either 1 or 0 (not both)

This very property of q bits to collapse into 1 or 0 enhances the security to the next level

Suppose q bits are like a rotating coin, when you stop to find which side is the coin facing, you end up getting head or tail, but the spinning coin had both of them

Suppose a server sends you a key in the form of q bits

If the actual key is 101011, encoded in the form of q bits

But when the q bits are sent no one knows what they were as everyone can measure them differently

When the q bits reach you and you measured them as 101110

In this case, the last and the 3rd last q bits differ, so you and the server compares the keys generated, and throw out the mismatches

In this way, you and the server get the exact key

If someone tries to break into the security of the system and finds the server-generated q bits

He can not figure out the encoded key

Because, he may measure the q bits differently, and end up getting another string of 1s and 0s

In fact, he wouldn’t even know at the first place that he measured them right or wrong

Know more

security using quantum entanglement, (e91 protocol)

e91 protocol involves the use of quantum entanglement, making communication even more secure

Another way of enhancing the security of a system is by using another property of q bits quantum entanglement

Quantum entanglement is a property of q bits to influence each other

For example

if two q bits are entangled in such a way that whenever the state of one q bits is 1 the state of the other will be 0 (regardless of how the second q bit is measured)

Now let’s see how this helps in improving the security

What happens, in this case, is that the server and you receive an equal amount of entangled q bits from a trusted 3rd party

Now as the q bits are entangled, the server can regulate the states of your q bits

The server itself will cause your q bits to form a key in this case

quantum computers explained

A quantum computer is a computer exploiting the unique quantum world phenomena and perform calculations involving a huge set of data or a number of possibilities, problems solved by quantum computers are not solvable by classical computers

Quantum computers are fundamentally different from classical computers because they use q bits to process information

And these q bits can be thought of as a spinning coin, which is both heads and tails at the same time

What are these q bits physically?

Q bits can physically correspond to 2 things -

Quantum states of atomic and subatomic particles
States of an electrical circuit can also correspond to states of q bits

Based on these 2 types of q bits, quantum computers can also be of two types

1. 1 trapped ion quantum computers
2. 2 superconducting quantum computers

One common thing in both these types is that they need to have q bits in the same place, for which they use different techniques and methods

1 trapped ion quantum computers

In this type of quantum computers, ions(or q bits) are trapped in a trap of electric fields

The state of trapped ions function as q bits here

The use of LASERS gives these ions inputs, and in response to them, they either emit photons or not emit photons (depending on the states of their q bits)

an imaging system collects these photons, which are analyzed to provide the required answer

Sign up to access World's first commercial trapped ion quantum computer experience

Advantages-

• Ions can be controlled precisely, so controlling the computers is quite easier
• Ions can last for a longer time; hence these computers have more stability

Disadvantages-

• Increasing the number of ions (or qubits) in a trap is difficult, and makes controlling them very difficult

2 superconducting q bit quantum computers

In this type, the q bits are controlled (or brought in one place) by reducing the temperature to about 10k (kelvins)

The electrical circuit used by these computers is a semiconductor ring with a junction known as Josephson junction

The direction of current flow in an electrical circuit determines the state of q bit

Here the interaction with the q bits takes place with the help of microwaves, instead of LASERS as in the previous case

Know more

Advantages

• Superconducting circuits can do quantum operations faster, making these computers faster
• It is easy to scale up the number of circuits; thus it is comparatively easy to scale up the q bits for complex calculations

Disadvantages

• The quantum state of these circuits is very fragile and can change even with the smallest changes in the surrounding environment

Early quantum computers

Early quantum computers basically had a chloroform solution in a test tube kept under a constant magnetic field

In fact, this quantum computers successfully found the desired number out of the set of 4 numbers

Early quantum computers had a solution of chloroform in a constant magnetic field

To understand the working of these early quantum computers we need to first understand the chemical structure of chloroform, and the type of q bits used

Chloroform structure

The chloroform molecules consist of 5 atoms with 4 atoms arranged at the corners of a tetrahedron and 1 atom at the center

Out of 5 atoms, there are 3 chlorine atoms, 1 carbon atom, and 1 hydrogen atom

The carbon atom is at the center and rests at the corners of the tetrahedron

Q bits used

The q bits used in this quantum computer were the spin angular momentum of hydrogen and chlorine atoms

And the interactions between these spins function as a quantum logic gate

Now we are all set to understand the working of these early quantum computers

working

1. complete apparatus is now placed in a constant magnetic field for the phenomenon of  nuclear magnetic resonance to occur
2. nuclear magnetic resonance in simple terms is a way to study the interactions between the molecules
3. Radio pulses with a broad range of frequencies are sent to interact with the molecules, and the responses are studied as a spectrum
4. In this way, we can interact with the computer

Challenges in building quantum computers

challenges involved in building a quantum computer with a large number of q bits are-

1. 1- sensitivity towards the environment
2. 2- extremely low temperatures

1- sensitivity towards the environment-

even the smallest of changes in the surrounding environment can affect their working

The very first and probably, the biggest hurdle in maintaining a quantum computer is their sensitivity

They are extremely sensitive even towards the slightest change in the surrounding environment

Even the slightest of the shocks, faintest of the sounds or even air molecules can hinder the working of quantum computers

A question may have arisen in your mind that how even such insignificant environmental changes can hinder such a powerful computer

The answer to this question is that these changes directly attack the q bits of quantum computers

Without these properties of q bits, a quantum computer will simply become a very cool refrigerator

2- extremely low temperatures

For working on a quantum computer it is important to control the q bits, meaning they should be in an energy state in which they don’t run here and there

Such low energy states are possible only at very very low temperatures

These low temperatures can be as low as 0k

Moreover, in superconducting quantum computers require such low temperatures by default as superconducting properties of a substance can exist only at those temperatures

extremely low temperatures are required to keep all the q bits in the same place

Can quantum computers destroy us?

quantum computers clubbed with artificial intelligence can prove to be dangerous

here’s why

Quantum computer can analyze a number of possibilities at once and find of the optimum ones amongst them

If a quantum computer with a known set of programs and a large database can find the best combination or possibility out of them

a quantum computer with artificial intelligence can thus program itself to the most intelligent state, a state of intelligence even higher than we humans

If something is even more intelligent than us then it may even try to finish the existence of humans

But you need to keep calm down because such possibilities are largely theoretical, and their reality may be a thing of far future

By then let’s experience the current quantum computers by IBM’s quantum computing experience

IBM’s quantum computer experience

IBM is one of the very first technology companies which has made this future technology available right at the fingertips of common people

In IBM’s quantum computing experience you will be able to do the following-

• Run your first quantum circuit
• Run your first quantum program
• Learn quantum computing

Here’s the link to IBM’s quantum experience

Google quantum computer

Along with IBM google has also been researching on quantum computing and have also developed their own quantum computer

To know more about google’s quantum computers click here 

Conclusion-

This article was a complete guide to quantum computing, and what miracles quantum computers can do

If you have any doubts or questions in your mind you can comment and tell us

We would also like to know what is your opinion of how will quantum computers shape our future

Either way, you can go ahead and comment