Physicists have filmed the oscillation of a time crystal

https://www.sciencealert.com/watch-the-first-ever-video-of-a-time-crystal-oscillating

by IFR • 5 years ago

288 100 5 years ago

sciencealert.com

tait• 5 years ago

Does anybody else agree the name "Time Crystal" could be better somehow?

nabla9• 5 years ago

No. It's technically very accurate name. https://en.wikipedia.org/wiki/Time_crystal

yesenadam• 5 years ago

(Not an expert) I read the first few paragraphs on that link. So, by analogy, we might call (normal) crystals with flaws "space crystals". Or maybe they should be "space-flawed crystals" and "time-flawed crystals" - a "flaw", in the usual sense, being a break in the regular crystalline structure. The adjective describes the (nature of the) breakdown in regular structure, not the regular structure. No? I wouldn't defend "space crystal" as a "technically very accurate name".

chadcmulligan• 5 years ago

I always think of doctor who when I hear it - not that its a bad thing.

jhloa2• 5 years ago

I like how much it sounds like futuristic science fiction technology!

Topgamer7• 5 years ago

But then how would I think about Crash Bandicoot and Neo Cortex whenever there is news!

867-53093• 5 years ago

yes, it sounds too mystic for science

how2cflags• 5 years ago

TimeSplitters Future Perfect - Cortez, get the time crystals!

tobmlt• 5 years ago

Frank Wilczek was hoping for a writers credit on the next Indiana Jones reboot.

contravariant• 5 years ago

The more verbose 'time-translational-symmetry-breaking-structure' isn't much better. So crystal it is.

userbinator• 5 years ago

It reminds me of https://en.wikipedia.org/wiki/Time_Cube

sitkack2• 5 years ago

https://timecube.2enp.com/

seism• 5 years ago

Far out! Here is the 13 second video from the Max Planck Society in all its glory: https://youtu.be/kUY3TglEUCU

koolba• 5 years ago

That is cool!

I've never seen such a weird aspect ratio on YouTube either.

techrat• 5 years ago

Honestly, the video just looks like someone re-inverted an image several times over using a fade. What am I missing?

airstrike• 5 years ago

Time crystals should be stable and coherent over long time periods, because they - theoretically - oscillate at their lowest possible energy state. The team's research shows that driven magnonic time crystals can be easily manipulated, opening a new way to reconfigure time crystals. This could open up the state of matter for a range of practical applications.
"Classical crystals have a very broad field of applications," said physicist Joachim Gräfe of the Max Planck Institute for Intelligent Systems.
"Now, if crystals can interact not only in space but also in time, we add another dimension of possible applications. The potential for communication, radar or imaging technology is huge."

andrewflnr• 5 years ago

Is there any particular reason it's unlisted?

armada651• 5 years ago

How do Time Crystals differ from the quartz crystals used for time keeping in electronics? Is the only difference that Time Crystals oscillate without needing an electric field?

mjfl2• 5 years ago

I also wonder how a time crystal is different from a harmonic oscillator.

kolinko2• 5 years ago

Harmonic oscillator can have a ground state where it doesn’t move (i.e. you can stop it if you remove the enegy).

Time crystals move at the ground state - you cannot stop them by removing the energy.

yccs276• 5 years ago

Normally, a system (like a quartz) which is driven by an external frequency, oscillates at the same or a multiple of the driving frequency. This is because the external conditions are symmetric under a time translation (i.e. a delay) by the period duration. This symmetry is normally preserved by the system.

A time crystal, however, will oscillate with a fraction (or rational multiple) of the driving frequency. This breaks the original time translation symmetry.

rkagerer• 5 years ago

I think you said that already :-)

dhdc• 5 years ago

From my very limited knowledge of physics, time crystals can theoretically oscillate forever without any excitation at their ground state, though laws of theromodynamics are not broken and energy cannot be extracted from their oscillations. In a normal crystal oscillater, power is needed to keep the crystal oscillating.

ezconnect• 5 years ago

I have no knowledge of them but the article says it oscillates at lower energy levels, almost nil, compared to a quartz crystals. Since it is still unexplored territory there are lots of possible applications.

kevin_b_er• 5 years ago

While this may be that they can oscillate forever, measuring it is an act of removing energy from it.

tryonenow• 5 years ago

In the experiment, the crystals were driven by RF excitation. Do time crystals generally require a constant energy source to oscillate? I would assume not, since they're called crystals...

Also, is the oscillation frequency temperature dependent?

yccs276• 5 years ago

Unfortunately, time crystals do require an external excitation. The key is that the excitation does not have the same frequency as the time crystal.

selimthegrim• 5 years ago

Exactly, thinking about a parametric oscillation might help

867-53093• 5 years ago

filmed at up to 40 billion frames per second

that's quite a feat on anyone's watch

bluefirebrand• 5 years ago

It probably was filmed on a camera not a watch.

867-53093• 5 years ago

whoosh

chovybizzass2• 5 years ago

how many frames per seconds are our eyes recording at?

DistressedDrone• 5 years ago

I can't tell if you're joking, but in case anyone else is wondering: Most people can perceive between 30-60 frames per second. Some (mostly gamers) reportedly perceive up to 120 frames per second. Though whether this counts as recording is a matter for philosophers.

This is many orders of magnitude more than that.

fsh2• 5 years ago

Our vision is not frame-based at all. Each receptor cell can trigger inependently. Chopping up the signal into image frames is simply a technical trick that makes us perceive continuous motion due to the finite recovery time of the cells (persistence of vision).

victorevector• 5 years ago

haha I cant wait to hear about this from my local rock/crystal dealer ooommmmmmmm shiva Shankarrrr mahatmahariiii ganjaaaaaa

darkwater• 5 years ago

When quantum mechanics are involved, I feel like someone from 400 years ago might feel today using a smartphone. And probably as a society we are now like starting to experiment with electricity. I wonder what will be the smartphones in that future.

auntienomen• 5 years ago

These physicists have never properly acknowledged the prior work of Otis Eugene Ray on this subject. How typical!

sitkack2• 5 years ago

Never forget! https://timecube.2enp.com/

allemagne• 5 years ago

"Now, if crystals can interact not only in space but also in time, we add another dimension of possible applications. The potential for communication, radar or imaging technology is huge."

Could anyone expand on this in an accessible way? What kinds of changes could we see in imaging or communication technology?

marricks• 5 years ago

I do not look forward to seeing how the US defense industry eventually utilizes this technology.

kderbyma• 5 years ago

just a random guess and hypothesis with absolutely no basis besides this article. I think they may be able to 'sync' up transmitters which are then used to encode and decode based on time and space. Like time-sensitive antennas which adds another means of encoding....???

yccs276• 5 years ago

Since the article doesn't do a good job of explaining what a time crystal is, here's my attempt at summarizing the Wikipedia article [0].

Normally, a system which is driven by an external frequency oscillates at the same, or a multiple of the driving frequency. This is because the external conditions are symmetric under a time translation (i.e. a delay) by the period duration. This symmetry is normally preserved by the system.

A time crystal, however, will oscillate with a fraction (or rational multiple) of the driving frequency. This breaks the original time translation symmetry.

The analogy with normal 'spatial' crystals is through this symmetry breaking: Empty space is symmetric under all translations, but a crystal spontaneously breaks the symmetry group down to the smaller set of 'translations by a multiple of the lattice constant'.

The continuous symmetry of time translations cannot be spontaneously broken, due to thermodynamic arguments. Instead, we explicitly break down the time translation symmetry to 'delays by a multiple of the period duration'. A time crystal then spontaneously breaks the symmetry down even further, by multiplying the period duration / dividing the frequency.

[0] https://en.wikipedia.org/wiki/Time_crystal

centimeter• 5 years ago

How does this compare to the behavior of nonlinear optical crystals like lithium triborate? They are also pumped at a lower frequency (e.g. 1064nm photons) but lase at twice that (532nm).

yccs276• 5 years ago

In some way, it's the inverse: a nonlinear optical system can multiply frequencies, while a time crystal divides a frequency. That's not as easy as multiplying, due to the symmetry concerns I mentioned.

It's basically a frequency divider, but as a system of cold atoms instead of an electronic circuit, and in a different frequency regime.

mwilcox• 5 years ago

I would say that gravitational waves break the idea that empty space is symmetrical

RIMR• 5 years ago

Could you elaborate on that?

yccs276• 5 years ago

I mean, you're technically correct (the best kind of correct). But in the lab, we're pretty safe with neglecting the effects of general relativity.

whatshisface• 5 years ago

Gravitational waves have momentum, energy and even mass, so I wouldn't call a box full of them empty.

k__• 5 years ago

What are potential applications?

Do the allow some kind of special optical devices?

dekhn• 5 years ago

When I hear "time crystal", I think "the wielder of this object can travel through time, or at least do something far out, like see past events", not "a crystal that when vibrated breaks symmetry".

7800• 5 years ago

And whenever I hear time crystal, I think of bad sci-fantasy 80s movies.

“Mondor, you must grab the time crystal before the second moon equinox, or the Flarborg will be released from their electronic pen and ravage us like they’ve never ravaged before!”

“Oh. Well, we wouldn’t want that would we?”

p1mrx• 5 years ago

Oh, but you can see past events while wielding (or not wielding) a time crystal.

Vision is far out: https://www.youtube.com/watch?v=FjHJ7FmV0M4

amelius• 5 years ago

I think of quartz crystals, used to measure time.

nom• 5 years ago

Maybe they can. Who knows what strange realms of physics this research leads us to.

dnautics• 5 years ago

I believe the most recent iteration of star trek is particularly guilty of stealing "time crystals" from the science news headlines and applying it to this sci-fi trope.

ww5202• 5 years ago

Every time the discussion of time crystal comes up, a simple analogy can explain what it is.

Regular crystal has repeatable structure in space, i.e. its lattice is the same shape over and over again across in space.

Time crystal is the kind of material that has repeatable structure across time, at the lowest energy state. It just means it changes its shape periodically over time.

An example of that is quartz crystal vibration where its structure bends and unbends over time. Quartz bending and unbending (vibration) is due to the piezoelectric effect when an external electric force is applied. The external force requirement disqualifies it as a time crystal.

The "at the lowest energy state" requirement means time crystal can "vibrate" by itself without external force applied. "Vibrate" is used loosely here. It could be the nuclear-spin flipped periodically, or some other structural changes that need no outside influence.

zbyte64• 5 years ago

Would it be accurate to say that the "Vibration" or nuclear-spin flipping doesn't emit energy or is neutral in the thermodynamic sense?

marton78• 5 years ago

A powerful and mysterious device, whos mystery is only exceeded by its power.

yccs276• 5 years ago

What you have described is an ideal time crystal. Unfortunately the time crystals we can create in the lab do need an external force, but this force can have a higher frequency than the oscillation of the crystal.

_8091149529• 5 years ago

For anyone struggling to make sense of this: I have a physics PhD, I have spent most of my career in fundamental research, I have read the Wikipedia article and other references multiple times, and attended several talks, and I still don't understand what qualifies as a time crystal. All I know that it seems to have something to do with subharmonic response.

systemvoltage• 5 years ago

The more deeper you get in a particular field, the more you realize how no one else has a clue. It's time we put credentials aside, I found this amusing: https://en.wikipedia.org/wiki/Michael_Crichton#GellMannAmnes...

WildParser• 5 years ago

I don't really know what those people in physics do, but as a mathematician my definition of a time-crystal would be a 4-dimensional discrete structure. You have some 4-dimensional symmetries.

Just rotating in 3D is a bit boring. Interesting symmetries would be where you get the time-axis involved.

4D is most likely a bit boring - having more dimensions and more time-dimensions helps greatly to get more symmetries to work with...

gubby• 5 years ago

Another scummy website that hijacks the back button. I wish there were a way to block domains from the results I see on HN.

smartestdumbguy• 5 years ago

I wonder how this links in to optical crystals? KTP, used in solid state lasers, will halve the frequency of a IR laser (1064nm) to produce green light (532nm).

I suppose this is equivalent to adding electrical energy to a crystal to make it oscillate.

fsh2• 5 years ago

532 nm corresponds to double the frequency of 1064 nm, not half. Any nonlinear response generates harmonics of a signal but not subharmonics. This is why in electronics a single diode can be used as a frequency doubler, but a digital flip-flop is required for frequency division.

segfaultbuserr• 5 years ago

What are time crystals? Try this:

* Physicists Predict The Existence of Time Crystals https://www.technologyreview.com/s/426917/physicists-predict...

* How to Build A Space-Time Crystal https://www.technologyreview.com/2012/06/26/255685/how-to-bu...

(Reposted from an earlier submission in 2016: https://news.ycombinator.com/item?id=12655530)

nexthash• 5 years ago

This is a wonderful development! Learning about far-out advances in physics is amazing, but they sometimes feel like they are too removed from everyday reality beyond helping us understand some semantic piece of how the Universe works. Does anybody know if time crystals have any practical uses?

brootstrap• 5 years ago

from the article at the end. suggest u read it hashman.

"Classical crystals have a very broad field of applications," said physicist Joachim Gräfe of the Max Planck Institute for Intelligent Systems.

"Now, if crystals can interact not only in space but also in time, we add another dimension of possible applications. The potential for communication, radar or imaging technology is huge."

chovybizzass2• 5 years ago

how the f do you guys know so much about this?

marshmallow_12• 5 years ago

why aren't electrons spinning round an atom called "time particles"? Technically by the time they run out of energy, the universe will have died so they are "super time particles".

zbendefy2• 5 years ago

I think they are not actually spinning, they are around the nucleus in a probability cloud. I dont think we could use that as a timing mechanism but Im not a physicist

soheil2• 5 years ago

So, where the structure of regular crystals repeats in space, in time crystals it repeats in space and time.

Does that mean anything that behaves like a wave is a form of time crystal? For example ocean currents moving in unison causes all atoms in that wave to follow a very specific pattern similar to what is described in the article.

soheil2• 5 years ago

I wish someone would show that charge parity time (CPT) symmetry can be broken so we'd have to rewrite the entire laws of physics from scratch but this time would do it more efficiently.

es7• 5 years ago

It sounds like these room-temperature time crystals must be driven by continually applying external energy via the driving frequency, or did I misread that?

Is it feasible to create my own time crystals? Or acquire one?

I would love to add a time crystal to my existing space crystal collection, even if it requires some sort of support to maintain the driving frequency.

I haven't read the paper yet, but it sounds like I could apply a particular frequency to a strip of nickel-iron alloy and practically achieve such an effect?

Do any physicists here know whether that would be feasible?

inimino• 5 years ago

Yes, with microwave RF and a magnetic strip in a static field you can make one, but just keep in mind you'll need an X-ray synchrotron and a 40 billion fps camera to see it.

solipsism2• 5 years ago

Is a spinning t-handle exhibiting the tennis racket effect a time crystal?

hatemben• 5 years ago

In 2001 I worked on spectral analysis of a jet-type flow and realized a PIV software with matlab. Of course images that I used issued from a high speed camera, have nothing to do with the 40 billion frames per second we are talking about here ! It was just fascinating to see the particles moving in milliseconds.

We are talking here about 40 Cycles Per Nanosecond !! It's not just fascinating, it's Hilariously crazy !

abootstrapper• 5 years ago

ELI5 why we can't make a perpetual motion machine out of this?

Physicists have filmed the oscillation of a time crystal

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