Time crystals

[mike]

The Berkeley-led team will attempt to build a time crystal by injecting 100 calcium ions into a small chamber surrounded by electrodes. The electric field generated by the electrodes will corral the ions in a “trap” 100 microns wide, or roughly the width of a human hair. The scientists must precisely calibrate the electrodes to smooth out the field. Because like charges repel, the ions will space themselves evenly around the outer edge of the trap, forming a crystalline ring.

At first, the ions will vibrate in an excited state, but diode lasers like those found in DVD players will be used to gradually scatter away their extra kinetic energy. According to the group’s calculations, the ion ring should settle into its ground state when the ions are laser-cooled to around one-billionth of a degree above absolute zero. Access to this temperature regime had long been obstructed by background heat emanating from trap electrodes, but in September, a breakthrough technique for cleaning surface contaminants off electrodes enabled a 100-fold reduction in ion trap background heat. “That’s exactly the factor we need to bring this experiment into reach,” Häffner said.

Next, the researchers will switch on a static magnetic field in the trap, which their theory says should induce the ions to start rotating (and continue doing so indefinitely). If all goes as planned, the ions will cycle around to their starting point at fixed intervals, forming a regularly repeating lattice in time that breaks temporal symmetry.

'Time Crystals' Could Upend Physicists' Theory of Time | Wired Science | Wired.com

What clever monkeys we are

 

[Randall]

What is being described here is another mathematical interpretation for what constitutes time with respect to the ions. The problem with it is that rather than actually involving time itself as a motivating force, the ions are simply set in motion along a circular path that returns each ion to the location ( relative to the confines of the experiment ) that it started from, and unfortunately that does not constitute a "break in the symmetry of time". For that matter the whole idea of "temporal symmetry" is faulty because time isn't symmetrical in the first place, so technically its symmetry can't be "broken". For this experiment to be something special its temporal asymmetry would have to be broken, and even if we suppose that it could, the experiment doesn't take into consideration the wider universe beyond the scope of the experiment, and therefore the position of the ions will never return to exactly their same starting point, and consequently cannot actually go "back in time". Cool experiment though, and sophisticated enough to bamboozle people into approving funding for it. I think these kinds of experiments are going to lead to other unexpected discoveries, like possibly how to manipulate the influence of gravity and store large amounts of energy in small spaces.

 

[exo_doc]

Interesting. I met the Nobel Prize winning researcher who first used lasers to halt the random motions of atoms to drop their temps to billionths of a degree Kelvin at Appalachian State back in 2001.
I wonder how they expect the calcium ions to maintain their atomic integrity at such an incredibly low temp and not dissipate into Bose - Einstein condensate? Maybe the magnetic trap will keep the condensate stable.

 

[Randall]

Interesting. I met the Nobel Prize winning researcher who first used lasers to halt the random motions of atoms to drop their temps to billionths of a degree Kelvin at Appalachian State back in 2001.
I wonder how they expect the calcium ions to maintain their atomic integrity at such an incredibly low temp and not dissipate into Bose - Einstein condensate? Maybe the magnetic trap will keep the condensate stable.

The experiment is only using a few ions and they are kept organized and separated inside a magnetic field, so at those temperatures, the effect they're hoping to get would essentially be a manifestation of a Bose - Einstein condensate state, not unlike what we see with superconductivity or superfluidity. However characterizing it as a "time crystal" that breaks "temporal symmetry" doesn't make sufficient sense. That being said, there is probably some other way of looking at the experiment that is internally coherent and therefore makes sense within that framework.

 

[exo_doc]

Yeah, I'm not getting the temporal symmetry thing either. Maybe something "frozen" in time? Time literally quits moving? Maybe?

 

[Randall]

Yeah, I'm not getting the temporal symmetry thing either. Maybe something "frozen" in time? Time literally quits moving? Maybe?

Well, like I was saying at the start, it seems to be based on the math. Although math can be internally coherent, it may not apply to anything outside it's own abstract context. The so-called perpetual motion induced by the magnetic field is not the same as a "break in temporal symmetry". Magnetic fields store energy and if that energy is transferred to the ion ring causing it to move, then kinetic energy has been transferred from the field to the ion ring. If the current keeps going inside the ring, then it's probably due to the electrons picking up the energy from the magnetic field and transporting it along the ring similar to the way that a superconducting electromagnetic electrical storage unit ( second kind ) does. In those units, electricity has no resistance and therefore will stay in the container indefinitely provided the temperature is maintained. They are actually very efficient, but you don't hear a lot about them ( I wonder why ). Anyway, if the electromagnetic field transfers energy to the electrons in an ion on the ring, it will destabilize the symmetry of the ring because the ion with more energy than its neighbor will push harder against its neighbors. Then at just the right distance, and with just the right power, that ion will transfer its energy to an adjacent ion, causing the space between them to move to that location. In a sense each ion is acting like a tiny capacitor and each time the charge is transferred you get movement. Hypothetically, when the magnetic field is removed, the movement should eventually slow to a stop as the energy is eaten up by the moving ions. So it's not really identical to a superconductor, but it's really close.

 

[Angel of Ioren]

Stuff like this is why I love science. They have a crazy idea and they are trying to prove it in a lab. Real science!