Most people, including myself at first, think that quantum computing is scary. It terrifies people, in a mystifying way. But in reality, “Quantum” isn’t that scary, you just need some time to wrap your head around the concepts. So let’s break it down so that we can understand this perplexing topic.

See that chandelier like looking thing? Yeah, that’s a quantum computer. In simplistic terms, a quantum computer is a faster and more advanced type of computer that can solve certain types of problems exponentially faster than classical computers. How does it do this? It does this by using special quantum properties that classical computers can’t use. These quantum properties are basically like superpowers for your computer and they include things like **superposition** and **entanglement**. With this being said, they also bring new problems to the table like **decoherence**.

## Bits vs Qubits

One of the biggest differences between classical computers and their superior counterparts, the bits vs **qubits**. Classical computers use bits to process and store information in the forms of 0 and 1. However, quantum computers use qubits which uses some quantum properties to allow the qubit to be in the stage of 0 and 1 at the same time. This because of a quantum property called **superposition**.

**Superposition**

Superposition allows a qubit to be in multiple states at once. We can think of this as a coin. When a coin sits on a table, it can be in the position of heads, or tails just like a normal computer can be 0 or 1. But, a qubit is more like when you spin a coin. It can be either heads or tails, and we don’t know what it will be until we measure a qubit or in the case of the coin, slap a hand on the coin to see if it’s heads or tails. This allows for quantum computers to arrange their bits in many more combinations allowing for faster processing speeds. Imagine I had a whole bunch of Xs written on a sheet of paper with one single Y written somewhere in between and asked for a classical computer and quantum computer to search for it. The classical computer would have to go through every single letter to test if it was an X or a Y. A quantum computer, on the other hand, could just check every single letter at the same time and find the location of the Y instantly. This demonstrates how quantum computers are exponentially faster than classical computers at some problems (more on that later).

## Entanglement

Entanglement, or as Einstein put it, “spooky action at a distance” is the ability for qubits to communicate with each other instantly no matter how far apart they are. First, it is important to know that all fundamental particles have something called *spin. *Now when they are measured, these particles can have 2 outcomes, spin up or spin down. When we measure the spin of a particle, it has a 50% chance of being spin up and a 50% chance of being spin down. However, when we measure the spin of 2 entangled particles, they will always yield different results as long as they are measured in the same direction. So if we measure the first spin up, the other will be spin down and vice-versa. Now, even if these 2 particles were measured lightyears away, once you measure the spin of the first particle, you automatically know the spin of the second. So theorists speculated that these 2 particles communicated with each other faster than the speed of light as it seems as though the measurement of one particle affected that of another. This theory is still up for debate with many explanations of this effect.

## Decoherence

Even though quantum computing brings some new superpowers to computing, it also brings some superpowered problems to the table as well. One of the biggest problems that researchers face is something called **decoherence**. Decoherence is the theory that when quantum systems interact with the environment, this eliminates the quantum behaviour in quantum systems essentially making qubits lose their superpowers. Things like light, sound, vibrations and many more can cause decoherence and jeopardize the ability of qubits to stay in a state of superposition or entanglement. This can lead to lost information and if we don’t eliminate decoherence we have no quantum computer. To improve coherence, we have something called quantum error correction which essentially uses entangled particles to detect and correct errors while keeping the state of qubits intact bringing one of the many solutions to fixing decoherence.

## Uses

Now, you may be asking when are quantum computers coming to the market? Well, in reality, there are already a few quantum computing services available to the public on the cloud. Yet, they still haven’t reached their full potential and there is still work being done to create a fully functional quantum computer. The only thing is, quantum computers are really only useful for things like optimization problems and natural simulation. Quantum computers can be really useful for simulating most complex atoms making them amazing for researching new drugs or cancer research. So, if you’re just browsing the internet or going through social media, you should probably just stick to your classical computer.

Key take-aways

- Quantum computers are the future of computing and can be exponentially faster than classical computers
- Quantum computers use qubits instead of normal bits giving them superpower like abilities
- Qubits can use quantum properties like superposition and entanglement to make them more efficient and a lot faster
- With new technology comes new problems and things like decoherence is a major problem when developing a quantum computer
- Finally, quantum computers probably won't replace your classical computer anytime soon unless you’re doing research or solving other optimization problems