Entering the New Age of Computing | Quantum Computing

Bagavan Marakathalingasivam
Geek Culture
Published in
10 min readApr 1, 2021


Loading up the old Minecraft

It’s Saturday and you have nothing to do, so you decide to have some fun and play a little minecraft! You load up a new world and wait for your computer to load all of those chunks of data. It finished loading after only 7 seconds and you start playing in your new world!

It only took a short amount of time, because it’s a new world and there is very little data the world needs to generate.

However, if instead of loading a new world, you load up a world that contains a bunch of data. You got a brand new pc and you start loading up this world. It takes a while, and after 3 hours you FINALLY loaded up your world.

Even though you have a really fast pc, it still wasn’t able to load all that data at once!

Well… It’s just minecraft. It’s not like it’s anything extremely important

But what if it was!

Now obviously, companies and governments aren’t going to use your regular pc to store large amounts of their data. Instead, they’ll be using something called a supercomputer!


Supercomputers, just like the name says, are basically really fast and big computers that are used to carry complicated tasks that require a huge amount of data and speed!

Let’s go back to minecraft. Using the fastest supercomputer, will allow you to load up all of that data in seconds!

But… what if there was something that could do that in a blink of an eye!

That might seem crazy, and something that would come out of a dream, but this reality is actually here! This can be done with quantum computing!🤯

We’re going Quantum

Quantum computers are computers that use quantum phenomenons to compute their data. Quantum is crazy, and is a complicated topic, but don’t worry, I’m going to try my best and explain quantum computing as simply as I can.

Let’s get a bit of a background knowledge to see how powerful quantum computers really are.

In October of 2019, Google announced they that achieved Quantum Supremacy for a certain task. They claimed that this task would’ve taken a regular computer 10, 000 years to complete! Can you guess how fast the quantum computer did it in?

200 seconds!

After that statement, IBM announced that their fastest computer was able to complete that task in 2.5 days! Proving Google to be wrong!

However, 2.5 days is still a long time, and 200 seconds is still waaaay faster! We can also consider the fact that IBM used their fastest computer, and yet it still didn’t come that close.

This is the amazing power of quantum computers!

Google’s Quantum Computer

So, in order to understand some of the concepts of a quantum computer, we have to first learn about some of the concepts of a regular computer.

Let’s start off, Bit by Bit (Get it?)

The Classical Bits

Classical Computers run on a special type of language called machine language. This language is boring, cause it only consists of 0s and 1s.

These 0s and 1s are also known as bits.

Each bit can either be a 1 or a 0, and basically act like an on and off switch, where 0 means off, and 1 means on.

1 bit would consist of 2 states, as it can either be a 1, or a 0.

Depending on how many bits there are, the amount of possible states will vary.

In case you still don’t understand, here are some examples of bits and the amount of states they have.

1 Bit — 2 States: [0] or [1]

2 Bits — 4 States: [00], [01], [10] or [11]

10 BIts — 1024 States: [0000000000], [0000000001], […], [1111111111]

As you can see, there are a number of possible states in just 10 bits!

Rather than writing out all of these possiblites for which states the bit can be in, we can use the following formula:

2ⁿ, where n is equal to the amount of bits there are.

Most computers consist of 64 bits. Meaning that there would be 1.8446744e+19 states!

This is the basic gist of bits. Now that you know that, let’s move onto quantum bits and how crazy they are!

Qubits (Quantum Bits)

When it comes to quantum computing, quantum bits, or qubits work a bit differently from regular bits.

The state of a qubit is known as a quantum state, which is a two-dimensional vector.

Similar to a regular bit qubits also have 2 quantum states, each corresponding to the 0 and 1 state in a regular bits.

The quantum state for a 0 is denoted as ∣0⟩, and the quantum state for a 1 is denoted as ∣1⟩. This is called a ket notation, and things like ∣0⟩ and ∣1⟩, are known as kets. In our case, these states can also be represented with vectors as:

Vector representation of both quantum states

These states are known as computational basis states.

You’re probably wondering what the and the mean. Well, they don’t really mean anything, they’re mainly there to show us that this is a quantum state.

Now, unlike regular bits, there are more than just 2 possible states, this makes it possible to perform certain tasks that a conventional computer can’t do.

For example, the state of a qubit can also be a 0.6∣0⟩ + 0.8∣1⟩

To break this down, 0.6 is multiplied by the ∣0⟩ vector, and the 0.8 is multiplied by the ∣1⟩ vector. Simplifying this will appear like so:

Simplifying the state of the qubit into a vector


One of the most common terms you’ll hear in anything quantum related is superposition. When it comes to quantum, superposition is when multiple states are added together to result in one, valid, state.

For example, many would say that 0.6|0⟩ + 0.8|1⟩ is a superposition of |0⟩ and |1⟩. This means that the state is a linear combination of |0⟩ and |1⟩.

Now you’re probably wondering why I chose 0.6 and 0.8 instead of any other numbers. Well, in order to understand that, we must first know what to call these numbers. Well, coming from a mathematical background you can say that these numbers are coefficients of |0⟩ and |1⟩. In quantum computing, we call these coefficients, amplitudes.

The reason why I chose these two numbers and not any others were because of this rule:

The sum of the squared amplitudes must equal 1.

This is why I chose 0.6 and 0.8, their squares (0.36 and 0.64) add up to 1. It’s also the simplest set of two numbers you can choose.

Quantum states are complex though, and so it’s hard to really choose which numbers to represent it by. This is why we denote these complex numbers with α and β. This means that the state will be shown as α∣0⟩+β∣1⟩.

With our rule, we will see that ∣α∣² +∣β∣² =1.

This is called the normalization constraint.

Qubits like their privacy… You’ll see 😉

Alright, when a qubit is in superposition, we actually don’t know what state it is in, not until we measure it. But you see, quantum is really funny because once you measure the qubit(s), it will automatically collapse from superposition into its basic states of 1 or 0.

When the qubit collapses, there isn’t always going to be a 50/50 chance of which state it will be in. Once the qubit is in superposition, it has a certain probability of being in each state. This probably could even be a 1/99, meaning there’s a 99% chance the qubit will collapse into state 1.


Another property that qubits carry, is called entanglement.

When two qubits are entangled, this means that they are somewhat connected to each other.

Visual Representation of Entanglement

And so if you change the state of one of the qubits, it will instantly change the state of the other qubit in a predictable way.

When we look at one of the entangled qubits, it will either be a 1 or a 0. In this case, let’s say it turned into a 1.

This means that even if you didn’t look at the other qubit, it would still become a 0.

It doesn’t matter how far they are. Even if they were billions of light years away, as long as they were still entangled, the state will still change.

Superposition and entanglement are what give quantum computers the ability to take fewer steps to perform tasks compared to classical computers.

But what can Quantum Computers do?

So now that we’ve learned the basics of quantum computers, let’s talk about some of the different applications of quantum computing.

Machine Learning & AI

Machine learning and AI have been revolutionizing the world. It’s come to a point where you can create your own AI projects at home for free!

The only problem, is that when you are training a model, it takes offly long time to train! Quantum computers can be used to speed up this process and to unlock new levels of machine learning!

Quantum machine learning delivers a whole new set of machine learning algorithms and applications! (And a ton of more complicated math)

Drug Discovery

It takes over 10 years for a company to discover a new drug, and bring it into the market! Obviously, this isn’t really practical and we need something to speed up this process.

Quantum computing can dramatically change that!

It can allow scientists and pharmaceutical companies to analyze large scale molecules. Classical computers are used to run millions of comparison of molecules. However, this takes a long time and when quantum computers start to become readily available, it will open doors for more advancements and cures for a range of diseases!

Cyber Security

As mentioned previously, quantum computers can complete tasks that may take hundreds of thousands of years for classical computers to solve, in just a couple of minutes! This also goes with encrypting data.

A lot of encryption is based on mathematical formulas, which would takes a ton of time for a computer to solve. This is because there is a lot of factoring involved when it comes to encryption, and starting with a huge number and trying to factor that is going to take a while.

Quantum computing can easily factor those large numbers and decode these encryptions. This is all thanks to a quantum algorithm called Shor’s algorithm. Now, I won’t go too deep into what this is, but essentially allows these quantum computers to easily factor large numbers quicker than classical computers.

However, with quantum computing we can do the opposite of decoding, and encrypt stronger keys making it harder for people to crack into the system.

🔑 Key Takeaways

Well, I guess we’ve finally approached the end of this article :(. But hey don’t worry, here are some of the biggest takeaways from this article.

  • Bits are binary digits consisting of a 1 or a 0 (on/off)
  • Formula for calculating number of possible states: 2ⁿ, where n is equal to the amount of bits there are.


  • Quantum computers are computers that use quantum phenomenons to compute their data.
  • The state of a qubit (quantum bit) is known as its quantum state, which is a 2-dimensional vector.
  • The quantum state for a 0 is denoted as ∣0⟩, and the quantum state for a 1 is denoted as ∣1⟩(Ket notation). A.K.A, the computational basis state


  • Superposition is when multiple states are added together to result in one, valid, state.
  • When a qubit is in superposition, it is in a linear combination of |0⟩ and |1⟩.
  • The coefficients of these states are known as amplitudes, and the sum of the squared amplitudes must equal 1. This is known as the normalization constraint.
  • Quantum states are complex, and so we denote these complex numbers with α and β. Meaning that the state will be shown as α∣0⟩+β∣1⟩.
  • When a qubit is in superposition, we don’t know which state it is in. Once we measure the qubit, it will automatically collapse into a 0 or 1.


  • When two qubits are entangled, this means that they are somewhat connected to each other. When you change the state of 1 qubit, it will instantly change the state of the other qubit predictably.

Quantum Applications

  • Quantum computing can be used with machine learning to speed up the process and open new machine learning algorithms
  • Quantum computing can be used to analyze large scale molecules, evidently enhancing drug discovery.
  • Shor’s algorithm is a quantalgorithmthm used for factoring large numbers easily. This opens gates to faster encryption and decryption.

Well, that’s all I have for now, but if you have any questions, you can always connect with me on LinkedIn. While you’re at it, why don’t you join my newsletter to see some of the things I’ve been up to as well!