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Physicists have filmed the oscillation of a time crystal

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Re: Physicists have filmed the oscillation of a time crystal

#91

Post by dingoegret »

systemvoltage wrote: post #88
_8091149529 wrote: post #73

Earlier quoted context omitted.

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.

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...

That was a good little read and mirrors my sentiments about media consumption exactly. People who have a specialized knowledge about a subject will often find themselves reading false information about serious topics from media about their subject of knowledge. Lowering the credibility of that media in their eyes and preparing themselves to be more skeptical of information output from that media. Then flip to another subject they are totally uninformed on and believe word for word everything that is said to them no matter how utterly ridiculous.

Re: Physicists have filmed the oscillation of a time crystal

#92

Post by warent »

kergonath wrote: post #87
zbyte64 wrote: post #67

Earlier quoted context omitted.

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

Spin waves are similar to vibrations (phonons) in a lot of respects, you still need energy to change a spin. That said, some aspects of thermodynamics are counter-intuitive (well, actually most of it is). Vibrations are present even at 0 K because of the uncertainty principle, and that’s true for spin waves as well as actual vibrations. It does not mean that any energy is created. The difference with time crystals is…

> Vibrations are present even at 0 K because of the uncertainty principle

Are you sure that's true? I can't remember the exact details but recall that being a common misinterpretation of the uncertainty principle

Re: Physicists have filmed the oscillation of a time crystal

#93

Post by 6nf »

danwills wrote: post #83
zbendefy wrote: post #81

Earlier quoted context omitted.

Its wierd because I could differentiate between 120Hz and 240Hz but I think its because the computer generates still images without motion blur. So 120Hz with perfect motion blur would be indistinguishable from 240Hz I think

If only it were that simple! There's no-such-thing as 'perfect motion blur', it's all a matter of taste. You can do things like open the virtual shutter to full-open (so that not a single virtual-photon reflected off the virtual-motion will be missed by the virtual-sensor), which makes the motion recorded during one frame continue directly (with no time 'gap') into the next frame. This can help make things seem 'smoo…

On a computer game you can spot the 240fps because of the intermediate frames when you have visual elements moving very quickly across the screen. It's not because of 'faster eyes' I don't think. Like when you move your mouse very quickly you'll see twice as many mouse cursors en route.

Re: Physicists have filmed the oscillation of a time crystal

#94

Post by kolinko »

kevin_b_er wrote: post #40
dhdc wrote: post #22

Earlier quoted context omitted.

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.

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

You don’t need to remove energy from an object to measure it.

If you shine a flashlight into a dark room, you are measuring the positions of objects inside, and those objects don’t lose their energy.

Re: Physicists have filmed the oscillation of a time crystal

#95

Post by kolinko »

mjfl wrote: post #13
armada651 wrote: post #6

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?

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

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.

Re: Physicists have filmed the oscillation of a time crystal

#96

Post by yccs27 »

ww520 wrote: post #65
yccs27 wrote: post #25

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…

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…

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.

Re: Physicists have filmed the oscillation of a time crystal

#97

Post by WildParser »

_8091149529 wrote: post #73
yccs27 wrote: post #25

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…

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.

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...

Re: Physicists have filmed the oscillation of a time crystal

#98

Post by inimino »

es7 wrote: post #75

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…

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.

Re: Physicists have filmed the oscillation of a time crystal

#99

Post by Darkphibre »

yccs27 wrote: post #35
mwilcox wrote: post #33

Earlier quoted context omitted.

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

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.

I don't know... atomic clocks are approaching precision that can measure the effects of time dilation due to gravity on the order of inches. They have to take into account daily tectonic tides.

> The precision of current optical clocks is astounding. You may have heard that time goes more slowly when gravity is strong due to general relativity. Optical clocks are so sensitive they can measure the different flows of time 2cm apart in height. If I lay a book on the table, the bottom of the book is slightly closer to the center of the Earth than the top, so experiences slightly stronger gravity. This difference is measurable with an optical clock. Optical clocks are so sensitive we can no longer average the time of multiple clocks together—the ground you or a clock are sitting on typically rises and falls by ~5cm a day due to land tides. The seismic motion of the ground currently limits our ability to measure time. https://arstechnica.com/science/2021/01/a-curious-observers-...

Re: Physicists have filmed the oscillation of a time crystal

#100

Post by tpxl »

6nf wrote: post #93
danwills wrote: post #83

Earlier quoted context omitted.

If only it were that simple! There's no-such-thing as 'perfect motion blur', it's all a matter of taste. You can do things like open the virtual shutter to full-open (so that not a single virtual-photon reflected off the virtual-motion will be missed by the virtual-sensor), which makes the motion recorded during one frame continue directly (with no time 'gap') into the next frame. This can help make things seem 'smoo…

On a computer game you can spot the 240fps because of the intermediate frames when you have visual elements moving very quickly across the screen. It's not because of 'faster eyes' I don't think. Like when you move your mouse very quickly you'll see twice as many mouse cursors en route.

Afaik you can also detect images that are present for a millisecond (eg white screen with one black frame at 1000fps).
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