41–50 of 111 posts
* 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)
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?
Unfortunately, time crystals do require an external excitation. The key is that the excitation does not have the same frequency as the time crystal.
Does anybody else agree the name "Time Crystal" could be better somehow?
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.
Does anybody else agree the name "Time Crystal" could be better somehow?
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…
These physicists have never properly acknowledged the prior work of Otis Eugene Ray on this subject. How typical!
Does anybody else agree the name "Time Crystal" could be better somehow?
It reminds me of https://en.wikipedia.org/wiki/Time_Cube
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?
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 b…