[dysfunctor]

I don't know anything about anything, but I want to enumerate some things I learned reading this article, and if someone actually knows what they're talking about and sees fit to take pity on me, please correct me so that I can understand what this actually means.

So a time crystal appears to be made up of real matter. The article mentions ions that are arranged in a certain particular way, cooled in order to reduce their energy, and this still makes sense so far.

So, the idea is to create a closed loop of sorts from a temporal perspective. I'm imagining an object as a set of states that the object can be observed in, and if there was a loop, it'd be possible to observe a certain sequence of states over and over.

The arrangement of the ions is important, and one of the properties is the spin, which is possible to change with a laser beam, because obviously.

Anyways, I guess the frequency of the oscillation of the ions changing spin, since they interact with each other in a domino fashion, can be controlled with the frequency of the laser.

They did this, and observed the ions changing in such a way where there was no driving influence and it's implied that the reason that this behavior was observed is because time symmetry was broken, which is just a fancy way of alleging that the universe is non-deterministic, I think.

Maybe this will eventually be useful?

[contravariant]

>They did this, and observed the ions changing in such a way where there was no driving influence and it's implied that the reason that this behavior was observed is because time symmetry was broken, which is just a fancy way of alleging that the universe is non-deterministic, I think.

Time translational symmetry and determinism have nothing to do with one another. Even a classical pendulum breaks time translational symmetry yet it's fully deterministic. In this cases they do break the symmetry in a more fundamental way, but it still doesn't say anything about determinism.

[dysfunctor]

So what are the implications of an object that breaks that symmetry? Would it be possible to observe an object in different times in the same state, or the same time in different states?

[semiel]

> So what are the implications of an object that breaks that symmetry? Would it be possible to observe an object in different times in the same state, or the same time in different states?

The object would be in a repeating set of states. First state 1, then state 2, then state 1, then back to state 2, etc.

This is not in itself surprising. Think of a pendulum, for instance. The difference here is that the motion is the lowest energy state. Over time, a pendulum swing decays. This does not: it will continue forever, if not disturbed.

The obvious next question is: isn't that perpetual motion? According to the normal dictionary definition of those words yes it is, which is why this is a fascinating discovery. However, it doesn't violate the normal arguments against perpetual motion, because there's no way to extract energy from the system. Anything you did to influence the motion would require adding energy.

[ivoras]

But... don't the process by which this is observed (I mean literally, the machinery used to measure it) introduce energy into (or draw it out) this system?

[timelincoln]

I definitely don't think the conclusion is that the universe is non-deterministic, the idea is that when energy is lost symmetry is broken, and motion through time seems to be analogous to shape in space, in terms of this symmetry breaking effect.

[dysfunctor]

Can you explain what you mean when you say motion through time, and shape in space?

I was under the impression that the whole idea of time symmetry revolved around being able to "zip/fold/traverse/map" both forwards and backwards in time. It's my understanding that such a concept would imply determinism, because time is really just a set of states, in the smallest possible interval of time.

I also don't understand why the time crystal loses energy over time if it is trapped in a temporal loop. I mean obviously there's not such a thing as perpetual energy, but I would think that the energy of a certain object at a particular frame in the set of states that is time, then when it returns to that state from either direction, it should be the same.

Edit: This is meant to be inquisitive, not necessarily interrogative. Thanks!