‘Time Crystals’ Could Upend Physicists’ Theory of Time
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Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#2"How can something move, and keep moving forever, without expending energy? It seemed an absurd idea — a major break from the accepted laws of physics."
An object in motion will remain in motion, until acted on by an external force.
The real interesting thing here is that something can move, but have no energy - potential or otherwise. Unlike things we are used to, if a time crystal train hit you you wouldn't feel a thing. (Well, not exactly, but it gets the point across.)
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#3This article seems like it is abstracting away what would actually make this experiment more interesting than, say, spinning a dinner plate in a vacuum in zero-g.
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#4"How can something move, and keep moving forever, without expending energy? It seemed an absurd idea — a major break from the accepted laws of physics." An object in motion will remain in motion, until acted on by an external force. The real interesting thing here is that something can move, but have no energy - potential or otherwise. Unlike things we are used to, if a time crystal train hit you you wouldn't feel a…
He's talking about acceleration, not really movement. But I don't think it's accelerating either, not really.
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#5The experiment is interesting and I'll like to read the results. But I don't like a few details, probably most of them are errors in the press release.
* Perpetual mobile:
It's theoretically possible to build a system that moves forever. But it's impossible is to connect it to some kind of generator to extract energy for free, while the system continues moving at the same rate. And the real systems have some kind of friction that dissipates a part of the energy, so the real systems usually stop in a while.
The few cases where the movement can last forever is the movement in the superfluids and the current in the superconductors. They are not very ordered systems like this 100 Ca ring so they are not cristal-like. But the movement of the electrons in a superconductor is very similar to the moment of the Ca ring.
* Tagging a Ca:
The problem with quantum systems is that they act strangely. If the system is small enough the Ca lost their individuality and become indistinguishable bosons. (I'm almost sure Ca are bosons, nor fermions.) So to describe their state you must use Slater permanent (or determinants) and not look at each one individually. So any perturbation changes the whole system and is not useful to tag one Ca. (If the system is big enough, you can approximate it classically, but 100 Ca doesn't appear to be very big.)
* Quantum Gravity:
The Quantum Theory and Special Relativity are joined since 1928 by Dirac. The same ideas were later used in QED, QCD, and all the Standard Model. So all the calculations of the collisions in the LHC use a theory that includes Quantum Theory and Special Relativity. And the only way to use Special Relativity is to have a common structure for space and time.
Those theories are not related to the continuity or discontinuity or periodicity of the space or time. Nobody knows how to joint Quantum Theory and General Relativity, but in my opinion the problem is not related at all to the existence of space-crystals and the inexistence of time-crystals.
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#6prophecy -- planning centuries ahead, directing the near past -- ability to puppet everybody under synchronous control.
Cool though.
14:8 If the LORD delight in us, then he will bring us into this land, and give it us; a land which floweth with milk and honey.
14:9 Only rebel not ye against the LORD, neither fear ye the people of the land; for they are bread for us: their defence is departed from them, and the LORD is with us: fear them not.
14:10 But all the congregation bade stone them with stones. And the glory of the LORD appeared in the tabernacle of the congregation before all the children of Israel.
14:11 And the LORD said unto Moses, How long will this people provoke me? and how long will it be ere they believe me, for all the signs which I have shewed among them? 14:12 I will smite them with the pestilence, and disinherit them, and will make of thee a greater nation and mightier than they.
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#7"How can something move, and keep moving forever, without expending energy? It seemed an absurd idea — a major break from the accepted laws of physics." An object in motion will remain in motion, until acted on by an external force. The real interesting thing here is that something can move, but have no energy - potential or otherwise. Unlike things we are used to, if a time crystal train hit you you wouldn't feel a…
He's talking about acceleration, not really movement. But I don't think it's accelerating either, not really.
A satellite in orbit is always accelerating as well, and will remain in constant motion if the orbit is far enough out (i.e. well beyond atmospheric drag).
I'm about half-way through this and it feels more and more like it was written by someone who would also ask why a permanent magnet can support a load against gravity without expending any energy - it's the same fundamental attribution error.
EDIT: In fact finishing it, I'm really confused as to what's new here. Giant external magnetic field, and stuff just coasting in a circle? Nothing about this feels implausible in a classical sense with a ring of charged ions.
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#8Time crystals and ion traps... I must have fallen asleep watching Doctor Who again.
Joking aside, this could be the E=mc^2 of our generation. We take for granted that the speed of light is the universal speed limit and that DNA has a helical shape, but a century ago we knew neither of these things. The internet, in the scheme of things, is still in its adolescence (at best). The thing that fascinates and scares me more than anything is that in 50 years science will have already advanced beyond recognition.
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#9Earlier quoted context omitted.
He's talking about acceleration, not really movement. But I don't think it's accelerating either, not really.
A satellite in orbit is always accelerating as well, and will remain in constant motion if the orbit is far enough out (i.e. well beyond atmospheric drag). I'm about half-way through this and it feels more and more like it was written by someone who would also ask why a permanent magnet can support a load against gravity without expending any energy - it's the same fundamental attribution error. EDIT: In fact finishi…
It's a popsci article. I wouldn't go criticizing the scientists based on this.
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#10Earlier quoted context omitted.
He's talking about acceleration, not really movement. But I don't think it's accelerating either, not really.
A satellite in orbit is always accelerating as well, and will remain in constant motion if the orbit is far enough out (i.e. well beyond atmospheric drag). I'm about half-way through this and it feels more and more like it was written by someone who would also ask why a permanent magnet can support a load against gravity without expending any energy - it's the same fundamental attribution error. EDIT: In fact finishi…
> A satellite in orbit is always accelerating as well, and will remain in constant motion if the orbit is far enough out (i.e. well beyond atmospheric drag).
If general relativity is correct, that system will generate gravity waves which will take away energy and the orbit will decay. This is a small effect, however, so we generally don't have to worry about it. E.g., Earth's orbit is decaying by about the width of a hydrogen atom every few hundred years.