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Quantum computing: The mystical crystals that flip-flop through time13 min read

September 7, 2021 10 min read

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Quantum computing: The mystical crystals that flip-flop through time13 min read

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This story is the second in a two-part series on Quantum computing and Google’s new discovery. Click here or on the image below to get better acquainted with Quantum computing so that you can understand Google’s invention a little better.

Alright then, you’re back! You’ve learned about Qubits, dead-alive cats, and chandeliers that can answer questions faster than you think of them, but in a world where anything seems possible there is one little problem: Quantum Computers don’t exist yet.

The problem

There seemed to be two main reasons why these world altering systems haven’t materialised:

Remember how all the data that you store as bits on your computer is stored within electrical circuits. Well, qubits have to be stored within subatomic, quantum particles that behave as wonky as qubits do. However, the sub-atomic “circuits” hosting the qubits are so fragile that the slightest vibration could cause their collapse.

Second, all the processes that go on in Quantum computing release heat. And this heat is more than enough to disturb quantum particles and once again cause the collapse of the qubits. That’s why instead of having millions of qubits of data that can fuel a quantum computer and unlock the secrets of the Universe, we have around a hundred qubits that can processed to solve a very specific question extremely fast.

The problem on the side

By this point, you’re probably thinking, “Ok, I understand different that patterns of ‘0s’ and ‘1s’ encode different messages and data, but how do a bunch of wires and electrical boards in a circuit understand the ‘0s’ and ‘1s’. Well, for a refreshing change, it’s surprisingly simple. The ‘0s’ and ‘1s’of Binary simply represent an electrical circuit that is either on or off. So binary is just patterns of ‘on- circuit’s and ‘off-circuits’.

Now, not to put words in your mouth, but you’re probably wondering: ” Wait, does that mean qubits are both on and off at the same time? HOWWW?”. Yup. That does. They’re lawless. And much to your brain’s disappointment, that’s exactly what that means.

The big news

But, this is the news so something has had to have happened for us to be yammering about it. And, from what we hear, that something is a pretty huge deal. In fact, some people have even gone so far as to say that this could be the biggest discovery of this whole century!

Google thinks they might have actually found order in this chaotic world of collapsing qubits, in the form of- you guessed it- time crystals!!!

In order to understand time crystals, we have to first take a good look at everyday crystals that look something like this.

Crystals

Have you ever wondered, what makes crystals different from other rocks? Yes, they’re beautiful to look at, and almost all video games have magic embedded in them but there is something at an atomic level that makes crystals unique. It’s their structure.

All matter is made up of collections of atoms and molecules. Even large mountains are just gazillions of different atoms and molecules clumped together. And while each material is made of very specific atoms and molecules (for example: water can only comprise of hydrogen and oxygen atoms), the way in which these particles are clumped together is random.

A comparison of the amorphous (left) and crystalline (right) clusters... |  Download Scientific Diagram
Image: Research Gate

On the other hand, crystals have specific regular and repeated symmetric patterns of molecules and atoms within them. That is why, different crystals made of the same material form in the same shape regardless of which part of the world they are formed in.

Snowflakes have distinct shapes like this. You can’t mistake them for anything else. Do you want to guess why? Yup, it’s because snowflakes are crystals.

That’s pretty amazing, isn’t it? Well, wait till you learn all about time crystals.

Time Crystals

I have some bad news. If you’re here because you think you’ll be thrust back in time at the end of this article, you’d better leave (although you’d rather not since time crystals– time travel inclusive or not– are mind-exploding).

So, let’s get back to business. Time crystals are particles that have repeating symmetric patterns in time rather and space. What? Okay, let’s break it down.

Lawless Crystals

Time crystals are too cool for school. In fact they’re so cool that they can’t even follow the simplest rules of the Universe. Nay, they’re not just cool, they’re just outright lawless. Time Crystals just unapologetically broke one of the most fundamental laws of physics, and all we can do is sit and watch. So let’s meet the law and the bandit who broke it.

The big fundamental law

So, one of the big laws of physics states that the Universe is constantly heading towards a state of chaotic disorder. This journey towards chaos is known as Entropy.

Before, you understand entropy, here are some other unchallenged (so far) laws of nature that you need to know: Every time that there is any movement anywhere energy is exchanged. But, it is important to remember that energy can neither be created nor destroyed. That means, the Universe already has a certain amount of energy that just travels between particles and objects but never disappears.

So when particles interact with one another they exchange energy. However, in the meanwhile they also lose some energy to other particles around them. And this energy goes “to waste”. This means that all particles keep losing energy in the form of heat, and as they do their behaviour becomes more and more disorderly.

Understanding Entropy

Think of a dancer, who dances for an entire day. At the start of the dancers performance the dancer will move beautifully and carefully. However, as the day progresses, the dance will become less beautiful and more tired. The dancer will have lost their energy and will no longer be able to control their movement.

On the other hand, the dancers movements will become smaller as their bodies will try to conserve energy. By the end of the week, the dancer will barely be moving but even then their movements will be uncontrollable and disorderly. For the dancer to get back up and start their beautiful dance again, they would need more energy. To get more energy, the dancer will probably eat something and get some rest, then the whole process could start again.

That’s how all matter works. Particles gradually waste and lose their energy to their surroundings and become more and more disorderly. However, they also become more and more stable in the state that they are in. Wait a minute, stay with me.

Stable Disorder

Let’s return to the day long dance. Imagine it’s the end of the day and the dancer is still on stage performing. You’ll notice that the dancer’s motion has decayed. Their movements are small, and in fact the dancer barely look like they are moving at all. Now, imagine that an angry member of the audience stood up and told the dancer to start dancing properly again. Even if the dancer wanted, they probably couldn’t satisfy the audience member. In a normal circumstance, the dancer would probably say something like, ” I am sorry I can’t help you because I’ve lost all of my energy”

However, if an audience member stood up in the morning, at the start of the dancer’s routine and said, “could you dance while barely moving and with disorderly movements”, the dancer could easily satisfy the demand of the audience member. That’s because the dancer had energy to spend, however without energy flowing through them, the dancer would have to be in a stable state.

So, now do you see how the dancer was far more stable when they had lost their energy? They were stuck in a state over which they seemed to have no control. However, when they had energy, they were unstable and could go back and forth between different kinds of movement.

This is sort of how matter works. As particles lose energy they become more disorderly, but they also become more stable or stuck in the state that they are in. In fact, anywhere in the world that you go, you’ll find that all matter behaves in this way.

Did you know that all particles are constantly bumping into each other and exchanging energy, and that’s why all particles in the Universe are always vibrating in random patterns!

The endless dance

So, how do time crystals beat this law? Well, order.

Imagine that there is a second dancer who continues this daily performance for days on end with no break at all. That means the dancer has no time to regain energy in the middle, and yet every morning the dancer must start twirling and jumping with beauty, precision and rigour. Sounds impossible right?

But what if the dancer was designed like that? What if that was just how the dancer existed? After a day of dancing, the dancer dances differently but feels the same. In fact, the dancer lost no energy at all. Then, at 6 am on the next day, they find that they are moving like they did on the first day again. Even though they’re dancing, they feel like they’re resting. By the end of the next day, they’re barely moving again and then come the third morning, the dancer is back to their big twirls and jumps. This loop goes on forever.

No energy to use

So, what has happened in this situation? The dancer has actually achieved a state of stability but has escaped the random disorder that comes with it. The resting state of the dancer is dancing. This person is as much of a dancer as they are a person. So much so, that from the time of their birth, they have danced all day in the same pattern of movement. You could say that the dancers movement is crystallised in time.

The most important condition of the dancers dance is that the dance routine has to be exactly the same everyday. If anyone were to ask the dancer to change their moves, the dancer would start to get tired and would eventually return to the original dance. This is because one particular pattern of movement is only natural for the dancer. For them to do anything else, they would have to use up energy.

The difference between time crystals and the rest of the Universe

The primary difference between the dancer in the first instance and the second dancer is that their state of exhaustion or rest is different.

In the same way, time crystals repeat molecular movement periodically. They alternate from one state of movement to another without using any energy. This is simply how they exist.

Unlike ordinary matter, time crystals are at rest in motion. Their symmetrical arrangement is in time rather than in space. So, while physical crystals may have patterns that make them occupy space in a certain way, time crystals are arranged in symmetric patterns in time. Time crystals continue to flip-flop between two different states while the rest of matter settles down in one state once the exchange of energy is over.

This is what scientists call the breaking of time translation symmetry. And this is probably the biggest super power of the time crystal.

Time-translational symmetry

If you look at matter closely anywhere in the Universe at any point of time, you will find that if the matter has exchanged most of the energy it could and is in a stable state, it’ll stay in that same state with its atoms vibrating with no real plan in mind. However, if you encounter a time crystal under the same conditions, you’ll find that at different times, it’s in two different states. So, as you travel though time in the atomic Universe, you’ll say everything look rather similar, either exchanging energy or resting in a stable state.

However, if you observe time crystals, you’ll notice a periodic pattern. The time crystal won’t be exchanging energy, but rather will be calmly flipping between states as it rests.

Another thought experiment

Imagine that you add a cube of ice to a glass of water and leave it out at room temperature. What do you think will happen? Slowly, the ice will lose heat energy and its molecules will start loosening and spreading apart. Eventually, the ice will melt completely and become a stable state of water. (Molecules start to spread apart as a substance changes from solid to liquid to glass).

Now, imagine if the ice cube was a time crystal. What could happen then? The ice cube could melt and reform into ice without anyone cooling the glass of water. What if you opened your freezer and found that at one moment you have ice cubes in your tray, but at the next you have water? You check if you’re freezer is cooling well, and it is. In fact, it has been at the same temperature for a while. Once you’ve put the ice in the freezer, you’d find that after the initial exchange of energy and “freezing” of the ice, the moment the ice is stable, it starts flip-flopping back between water and ice!

All other known phases, like water or ice, are in thermal equilibrium: Their constituent atoms have settled into the state with the lowest energy permitted by the ambient temperature, and their properties don’t change with time. The time crystal is the first “out-of-equilibrium” phase: It has order and perfect stability despite being in an excited and evolving state.

Quanta Magazine

This is what makes time crystals a new state of matter, because unlike the other three states of matter, time crystals have symmetric patterns of movement as time passes.

What happens next?

Someday in the near future, everyone may be able to build a quantum computer in their homes! Even you! But we still have a lot of hard work, patience, and time away from getting a cure to cancer or traveling at the speed of light. And we haven’t understood it completely yet. 

Convenient packaging

To understand all this a little better imagine that you had to store a note written on a piece of paper and transport it across the globe, thereby sharing that message on the note with everyone. In front of you, you have a metal box and a glass case. To preserve the note you would instantly think that you should store the note in the box of metal. But, there’s a catch. The note has a magic ink that makes it unreadable once it’s out of its casing. This means you’d have to use the glass case. However, the glass is so fragile that it’ll probably break in transit and end the notes journey.

The subatomic quantum particles that store qubits are much like the glass case. That’s why qubits keep collapsing and with it we lose all the data stores in them. But, now imagine you discovered plastic. What if you could store the note in a transparent plastic case that’s not fragile like glass and yet allows you to read the note?

Time crystals are like the plastic case. If they can be created and utilised, they can store cubits without losing energy, creating massive amounts of heat or collapsing! Here are just a few things that the discovery of plastic has made possible. Now imagine the leaps we could take with time crystals.

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