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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

#81

Post by zbendefy »

DistressedDrone wrote: post #71
chovybizzass wrote: post #61

Earlier quoted context omitted.

how many frames per seconds are our eyes recording at?

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.

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

Re: Physicists have filmed the oscillation of a time crystal

#83

Post by danwills »

zbendefy wrote: post #81
DistressedDrone wrote: post #71

Earlier quoted context omitted.

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.

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 'smoother' for sure but it's still relying hugely on persistence-of-vision.

I'm super surprised (and a bit incredulous tbh!) to hear of a perceivable difference between 120 and 240fps! need to go double-blind on that stuff to be sure I reckon!

Re: Physicists have filmed the oscillation of a time crystal

#84

Post by fsh »

smartestdumbguy wrote: post #29

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.

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.

Re: Physicists have filmed the oscillation of a time crystal

#85

Post by fsh »

chovybizzass wrote: post #61
867-5309 wrote: post #16

>filmed at up to 40 billion frames per second that's quite a feat on anyone's watch

how many frames per seconds are our eyes recording at?

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).

Re: Physicists have filmed the oscillation of a time crystal

#86

Post by hatemben »

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 !

Re: Physicists have filmed the oscillation of a time crystal

#87

Post by kergonath »

zbyte64 wrote: post #67
ww520 wrote: post #65

Earlier quoted context omitted.

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…

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 that usually these vibrations don’t involve any symmetry breaking.

Time crystals are consistent with standard thermodynamics.

Re: Physicists have filmed the oscillation of a time crystal

#88

Post by systemvoltage »

_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.

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...

Re: Physicists have filmed the oscillation of a time crystal

#90

Post by [deleted] »

dekhn wrote: post #47
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…

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".

[deleted]
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