Time crystals?

[Dave]

http://www.sciencealert.com/scientists-have-just-announced-a-brand-new-form-of-matter-time-crystals

Still trying to get my head around it, but it looks intriguing.

[Recusant]

http://www.sciencealert.com/scientists-have-just-announced-a-brand-new-form-of-matter-time-crystals

Still trying to get my head around it, but it looks intriguing.

You and me both! I've spent some time trying to learn what a time crystal actually is, and the most non-physicist-friendly explanation I've found so far is from MIT Technology Review.

[Arturo]

I don't understand....If it repeats in time, what makes that different from a regular crystal?

[xSilverPhinx]

[Dragonia]

Ok, I read these 2 articles and tried really super hard to get a little grasp on the concept at least, but it's mostly beyond my understanding....
So I'm curious, what would we do with these time crystals, if we could harness them? What applications might they have? Because I don't understand what "quantum memory" means. 

[xSilverPhinx]

Ok, I read these 2 articles and tried really super hard to get a little grasp on the concept at least, but it's mostly beyond my understanding....
So I'm curious, what would we do with these time crystals, if we could harness them? What applications might they have? Because I don't understand what "quantum memory" means. 

Good question. 

...

Very good question. 

[Recusant]

Ok, I read these 2 articles and tried really super hard to get a little grasp on the concept at least, but it's mostly beyond my understanding....
So I'm curious, what would we do with these time crystals, if we could harness them? What applications might they have? Because I don't understand what "quantum memory" means. 

In one of the articles I read they mentioned the possible use of time crystals in developing a quantum computer. Quantum computers are mostly theoretical right now, though people are working on trying to create them. What follows is a rough description, but it might help give a glimpse into the ideas here.

A quantum computer uses quantum superposition (oversimplified: the ability of particles to be in multiple states), to store and manipulate information. Instead of bits being binary (either 1 or 0) as in the computers we use right now, in a quantum computer there would be more than just those two states. I don't know what the physicists who work on this concept call the non-binary states, but I'll just use fractions. So a bit in a quantum computer might be say 0 or 1/4 or 1/2 or 3/4 or 1.

However, quantum decoherence is a problem. This is the tendency of a quantum system to "forget" the state it's in as it interacts with the world. In our computers, once the bit is set to 1 or 0, it stays that way until changed, but a bit in state "3/4" in a quantum computer will sooner or later change to a different state just because the computer is being used. That's no good.

Time crystals, according to the Wikipedia article I read, resist this quantum decoherence. If they could be used in quantum computers that would help solve the problem I described.

I'm pretty sure the above isn't precisely accurate, as I said, and I would welcome any corrections, but it's what I've understood from the articles I've read, and from previous reading about quantum mechanics.

[Dave]

Ok, I read these 2 articles and tried really super hard to get a little grasp on the concept at least, but it's mostly beyond my understanding....
So I'm curious, what would we do with these time crystals, if we could harness them? What applications might they have? Because I don't understand what "quantum memory" means. 

Somebody once asked what use the laser was.

And what use the telephone? There were enough telegraph boys for those important enough to need to send urgent messages.

Etc.

You never know 'till you know.

[joeactor]

Ok... so I also found this article:
https://physics.aps.org/articles/v5/116

with this picture:


I get quantum computing (mostly), but still haven't got a clue on Time Crystals.

[Tom62]

I get quantum computing (mostly), but still haven't got a clue on Time Crystals.

Don't they power the TARDIS  ?

[xSilverPhinx]

So would a time crystal still have motion at zero Kelvin?

[joeactor]

I get quantum computing (mostly), but still haven't got a clue on Time Crystals.

Don't they power the TARDIS  ?

[Arturo]

I guess if it repeats in time then it can (seemingly) be in 2 places at once. Or is that a worm hole? Idk.

[Recusant]

I guess if it repeats in time then it can (seemingly) be in 2 places at once. Or is that a worm hole? Idk.

The idea is that elements of a time crystal (ytterbium atoms in one of the experiments) move in a repeating pattern even when there is no energy being imparted to the system (the "ground state"). Normal matter in its ground state is in equilibrium; basically motionless. The matter in a time crystal theoretically never reaches equilibrium. Elements of a time crystal are not in two places at the same time, but periodically they return to the same place. 

I looked on YouTube for videos that explain what the scientists say is going on, and found several--all of them rather annoying, in various different ways. What is it with the roboticised voices? Three of the videos I found used this ridiculous gimmick. The one below has an OK explanation--the voice is roboticised, but not quite as thoroughly as the other two. 

[Arturo]

Oh ok. I understood the part where it seems to jiggle but has no energy. But maybe that's just me because my brain likes things that contradict.