Quantum Physics? Nah, Quantum Computing.

Okay, quantum computing takes some knowledge of quantum physics- but don’t worry if you’re bad at it, I failed physics as well.

When you hear the word quantum, more often than not your mind would finish the sentence with “physics”. I don’t blame you, before learning about quantum computing, that was my situation as well. Quantum physics deals with matter and energy on the sub-atomic particle/atom scale, so if you’re trying to figure out how electrons would move through a light bulb- you’re going to have to utilize quantum physics.

But that’s not what we’re here for.

Picture this:

I have a beautiful vase of flowers (thank you to the person whose pseudonym is Shawn). Lets say, there’s 2 roses, 10 carnations, and 2 eucalyptus leaves. I’m trying to find out how to position them the best way possible in order to get the PERFECT picture, but how many possibilities are there? I only have 5 minutes to take these pictures because I need to get back to work but let me do some math:

There are 14 stems in total, I have to use factorials in order to find out how many different options I have when trying to rearrange these flowers, so 14 factorial is….

8717891200????…. I don’t even know how to say that number…

Think it’s possible for me to rearrange these flowers eight billion times? Sure, but I’d rather not.

If I had a quantum computer, this wouldn’t be a problem. Quantum computers are meant to compute large numbers in order to find the best possibility there is in a matter of MINUTES. So eight billion positions wouldn’t be too much of a problem for the sake of my 500 followers on Instagram.

You gave me an example of an instance where quantum computers might help, but what is quantum computing?

Quantum computing is a field of computing that is based on the principles of quantum theory (the physical properties of nature described in the atomic and subatomic level) in order to develop computer technology.

Before we dive into anything further, keep in mind that classical computers store information in bits. In quantum computers, the information is stored in qubits and they represent atoms, ions, photons or electrons. That’s how small the information we’re dealing with will be.

Why will quantum computing help?

We have two quantum effects, superposition and entanglement. Superposition and entanglement allows computers to be much more sensitive for the sake of preciseness.

A superposition is a system where you have several states that can define it, and what you’re dealing with exists in those several states at the same time. When you measure your object, it drops out of superposition and lands on one of the several states that can define it. Classical computers will turn the information they get into a string of zeros and ones (think of it as True/On or False/Off). When information is processed in a quantum computer, it becomes quantum information that can be enabled to exist in a superposition of zeros and ones (but these zeros and ones will be qubits in terms of quantum computing).

If you’re having a hard time comprehending this, think of it like this:

You have a penny, and two different outcomes. The penny’s superposition will be four because it can exist in four different states (including at the same time) → (T, H) (H,H)(T,T) (H,T)

Entanglement is when the states cannot be described without being reliant on the other factors in computing, this means that measuring your first object will give you information about the second object without looking at the second object regardless of the distance, and so on. Here’s a cute little comic that might help:

Optimization

You will take your qubits (which are quantum information) and you go into a superposition of all the possible states, then when you encode the problem- you’re applying a phase on each of the states and then you’re using interference where you cancel some of the outputs and amplify the rest. You continue this process where you go into a superposition with the remaining points and cancel/amplify points until you’re left with no more. In short, this can speed up the processes of complex problems in the world. We can develop drugs faster and speed up the learning process of AI!

How do we build a quantum computer?

Qubits are extremely difficult to make because of how stubborn they are when it comes to manipulating them. Ironic because any interference can cause the qubits to fall out of their Quantum state.

Dr. Talia Gershon, an IBM Researcher, revealed IBM’s way of making their own qubits. Summarized:

We need to have qubits that are compatiable with quantum computing. For this, we make artificial atoms (which behave quantum mechanically). These are made out of superconducting Joesphson junctions along with microwave resonators.

This is a quantum computer from IBM. The squares are qubits and the squiggly lines are the microwave resonators. Inside the qubits will be the superconductive josephson junctions that were cooled down to 0.015 Kelvin.

In order to connect with these qubits, we use microwave cables inside of a dilution refrigerator. The dilution refrigerator is used to keep the superconductive josephson junctions cold. The microwave pulses from the cables allow the qubits to execute the require tasks.

Well, I want a quantum computer…wher-

Hold on, I want one too. Unfortunately, there isn’t one on the market yet. Companies such as NASA, Intel, and Google are on the race to building the next, best thing- a functioning quantum computer. For now, you can keep up with the most recent accomplishments like Google’s embryonic quantum computer solving a problem that the majority of supercomputers failed to do.

Quantum computers seem like the solution to every single problem there is in the world. As stated above, big companies are racing to build a functioning quantum computer. Considering we’re in a pandemic currently, quantum computers could’ve given us a vaccine for COVID-19 months ago. But, why is it taking so long for hundreds of engineers to develop ONE machine?

Decoherence.

Decoherence has been the biggest obstacle to overcome when building quantum computers. It deals with the wave-like properties of a qubit. It’s when the interaction between qubits and the environment causes the qubits to lose their quantum states, thus losing information that was previously stored by the quantum computer. Since quantum computers are dealt with at the subatomic and atomic level, any sort of vibration or wave can cause qubits to get out of their quantum state.

This can happen when:

• There is even a subtle change in magnetic and/or electric field
• The radiation from warm objects
• The cross-interactions between qubits

The Heisenberg uncertainty principle states that it is impossible to simultaneously measure the x-components of position and of momentum of a particle with an arbitrarily high precision.

a.k.a if we measure one aspect of a system precisely, we will lose information about another aspect. Quantum computers were meant to work around this principle.

Think of squeezing a stress ball. When we squeeze a stress ball, we make the part we’re squeezing much skinner than the part we’re not squeezing. The part we’re not squeezing becomes much bigger. When putting this into quantum computing terms, when we squeeze a quantum state, the size of the stress ball will be replaced with uncertainty.

The LIGO Scientific Collaboration recently added the concept of “squeezing” to their solution of boosting the sensitivity of quantum computers with quantum mechanics. They used interferometers, instruments where two light paths are utilized to make a precise measurement, to create an interference pattern. An interference pattern is obtained by two different waves (usually electromagnetic waves) of the same frequency intersecting at an angle.

At first, they started off with one interferometer which sucessfully detected small changes in the relative distance between two paths. But soon, they implemented three in order to minimize the doubt in each detected event.

The result? 50% more changes in gravitational events were detected compared to before.

Once quantum computers exist, there is no doubt that the world will change forever. If we have a future pandemic in the future, we won’t be spending more than 10 months in quarantine. It’s going to be more like 10 weeks. But, developing a quantum computer is hard since what you’re working with can’t be seen by the plain eye, give it up for these amazing scientists and engineers who are trying to reinvent the world by dealing with pratically invisible things.

Do you have a solution for decoherence? Tell me your thoughts!

TL:DR

• Quantum computing deals with the subatomic and atomic level of physical properties
• Quantum computers are mainly used to speed up processes that classical computers can’t accomplish or are really slow at
• The LIGO Scientific Collaboration found a way to minimize decoherence, although it’s not perfect, we’re making progress