[vanattab]

Can you elaborate on how this is different from how a quartz crystal works. I assume it's related to the following.

>That’s the “ticking.” In addition, the ticking in a time crystal is locked at a particular frequency, even when the pulse flips are imperfect.

I assume this is not true for quartz?

[jdrov]

I'm not an expert in quartz, but I'd assume there are physical "mechanical" oscillations with a hopefully-small distribution of frequencies around a given frequency, which is known to some particular degree of accuracy.

The "ticking" in our system is a periodically flipping nuclear-spin magnetization (rather than mechanical oscillations) whose period is definitely centered at twice the input drive period.

[ww520]

Quartz crystal vibrates due to the piezoelectric effect. External electric current is applied to the quartz to force it to physically bend. When it bends, it triggers the circuit to shut off the external electric current. With no external electricity applied, the bent quartz reverses back to its original shape and its piezoelectric property generates a small electric current in the unbending process. That current triggers the circuit to open the external electric current again, bending the quartz again. This bending and unbending creates the vibration.

Time crystal I gather just vibrates (ticking) by itself with no external power, which is amazing. In this case, it's at the sub-atomic level rather than at the crystal lattice level of the quartz.

[posterboy]

Interesting, I only knew the piezo diaphragms that need a frequent pulse drive to vibrate, probably because the energy need and loss in the process is much bigger for the amplitudes needed by audible vibration.

[ww520]

Piezoelectric effect can be applied differently to have different applications. In the piezo diaphragm case, the electric pulse is the frequency driver. If the electric pulse runs at once per second, the diaphragm is moved once per second (bending and unbending once per second). If the pulse runs at 1000/sec, the diaphragm is moved at 1000/sec (1kHz), producing a different pitch of sound. With different frequencies of electric pulse, you can produce different frequencies of diaphragm movement and different pitches of sound.